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Purpose: GC1118 is a novel antibody targeting epidermal growth factor receptor (EGFR) with enhanced blocking activity against both low- and high-affinity EGFR ligands. A phase 1b/2a study was conducted to determine a recommended phase 2 dose (RP2D) of GC1118 in combination with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) (phase 1b) and to assess the safety and efficacy of GC1118 plus FOLFIRI as a second-line therapy for recurrent/metastatic colorectal cancer (CRC) (phase 2a)., Materials and Methods: Phase 1b was designed as a standard 3+3 dose-escalation study with a starting dose of GC1118 (3 mg/kg/week) in combination with biweekly FOLFIRI (irinotecan 180 mg/m2; leucovorin 400 mg/m2; 5-fluorouracil 400 mg/m2 bolus and 2,400 mg/m2 infusion over 46 hours) in patients with solid tumors refractory to standard treatments. The subsequent phase 2a part was conducted with objective response rate (ORR) as a primary endpoint. Patients with KRAS/NRAS/BRAF wild-type, EGFR-positive, recurrent/metastatic CRC resistant to the first-line treatment were enrolled in the phase 2a study., Results: RP2D of GC1118 was determined to be 3 mg/kg/wk in the phase 1b study (n=7). Common adverse drug reactions (ADRs) observed in the phase 2a study (n=24) were acneiform rash (95.8%), dry skin (66.7%), paronychia (58.3%), and stomatitis (50.0%). The most common ADR of ≥ grade 3 was neutropenia (33.3%). ORR was 42.5% (95% confidence interval [CI], 23.5 to 62.0), and median progression-free survival was 6.7 months (95% CI, 4.0-8.0)., Conclusion: GC1118 administered weekly at 3 mg/kg in combination with FOLFIRI appears as an effective and safe treatment option in recurrent/metastatic CRC.

Aim: The OPTIM1SE study observed long-term real-world outcomes of cetuximab-based infusional 5-fluorouracil (5-FU) regimens for first-line treatment of metastatic colorectal cancer (mCRC) across Asia-Pacific and Middle East regions, aiming to characterize their use, effectiveness, and safety in routine practice., Methods: OPTIM1SE was a prospective, open-label, observational study. Patients with untreated KRAS wild-type mCRC and distant metastases were treated per locally approved labels and monitored for 3 years via electronic medical records. The primary endpoint was the overall response rate (ORR). Secondary endpoints included safety, progression-free survival (PFS), and overall survival (OS)., Results: From November 19, 2013, to June 30, 2016, 520 patients were enrolled in 51 sites. Patients were mostly male (61.2%), with a mean age of 58.5 (±12.0) years; 420 patients received leucovorin, 5-FU, and irinotecan-based regimens and 94 received leucovorin, 5-FU, and oxaliplatin. The most common primary tumor site was the rectum (38.8%), with liver metastases (65.0%). ORR was 45.4% (95% CI, 41.1%-49.7%), including 26 patients (5.0%) with a complete response. Median PFS was 9.9 months (95% CI, 8.2-11.0); median OS (mOS) was 30.8 months (95% CI, 27.9-33.6). Higher mOS was associated with tumors of left compared with right-sided origin (hazard ratio, 0.69 [95% CI, 0.49-0.99]); higher ORR was also associated with liver metastases compared with all other metastases (55.4% vs. 40.2%). Adverse events were consistent with the known safety profile of cetuximab., Conclusion: Cetuximab-based 5-FU regimens were effective first-line treatments for mCRC in routine practice, particularly in patients with left-sided disease and liver metastases only., (© 2023 The Authors. Asia-Pacific Journal of Clinical Oncology published by John Wiley & Sons Australia, Ltd.)

Although gastrointestinal stromal tumors (GISTs) are rare disease and rectal GISTs is only 5% of total GISTs, they have the worst prognosis. Due to narrow pelvis, tumor rupture or positive resection margin are common in the management of rectal GISTs. The impact of neoadjuvant treatment on the clinical outcomes of rectal gastrointestinal stromal tumors (GISTs) remains unclear. Thus, we conducted a retrospective study to investigate the impact of neoadjuvant imatinib on rectal GIST. The cohort comprised 33 patients; of them, 10 and 23 belonged to the neoadjuvant (i.e., those who underwent neoadjuvant imatinib treatment) and the control group (i.e., those who underwent surgery without prior imatinib treatment), respectively. Neoadjuvant group was associated with more common levator ani muscle displacement (P = 0.002), and showed significantly larger radiologic tumor size (P = 0.036) than the control group. The mean tumor size was significantly decreased after imatinib treatment (6.8 cm to 4.7cm, P = 0.006). There was no significant difference in resection margin involvement (P >0.999), and sphincter preservation rates (P = 0.627) between the two groups. No difference was observed with respect to morbidities, hospital stay, local recurrence and disease-free survival. Neoadjuvant imatinib treated group had similar propensity with control group after treatment. We thought reduced tumor sized could enhance resectability and provide more chance to preserve sphincter for rectal GIST patients. Considering large tumor size and higher rate of sphincter invasion in the neoadjuvant group, imatinib treatment could be helpful as a conversion strategy to make huge and low-lying rectal GIST operable and achieve better surgical outcomes., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Some patients with cancer may present with progressive or persistent disease at a limited number of sites following a period of treatment response. We evaluated the safety and effectiveness of metastasis-directed radiotherapy (MRT) for oligoprogressive or oligopersistent disease in patients receiving systemic treatment for metastatic colorectal cancer (mCRC)., Patients and Methods: Patients with mCRC who received 5-fluorouracil, leucovorin, and oxaliplatin; 5-fluorouracil, leucovorin, and irinotecan; and/or capecitabine chemotherapy between 2011 and 2020 at a single institution were identified. Then, those who underwent MRT for five or fewer lesion sites while receiving systemic treatment for other metastases were categorized. The primary endpoint was time to change to systemic therapy. Secondary endpoints included MRT-related toxicity, overall survival, and local control., Results: Among 4157 patients included, 91 (2%) received MRT to limited lesion sites (55 oligoprogressive and 36 oligopersistent) during systemic treatment following a period of treatment response. The median time to change to next-line systemic therapy was 5 months in the overall cohort (measured from the current chemotherapy session) and 9.5 (range, 6.0-40.6) months in the MRT group (measured from the MRT session). No severe toxicity or systemic treatment interruption was observed following MRT. The 1-year local control and overall survival rates were 69% and 99%, respectively., Conclusion: In patients with oligoprogressive or oligopersistent mCRC, MRT may be performed safely in conjunction with systemic treatment to maximize the benefit of systemic therapy and to prolong the time to change to systemic therapy. Further prospective studies should confirm these findings., (Copyright © 2021. Published by Elsevier Inc.)

Background: Preoperative chemoradiotherapy (PCRT) followed by surgery and adjuvant chemotherapy is the current standard treatment for stage II/III rectal cancer. However, radiotherapy in the pelvic area is commonly associated with complications such as anastomotic leakage, sexual dysfunction, and fecal incontinence. Recently, the MERCURY study showed that preoperative high-resolution magnetic resonance imaging (MRI) helped to selectively avoid PCRT. It remains unclear whether PCRT is necessary in patients who can achieve a negative circumferential resection margin (CRM) with surgery alone and in patients with cT 1-2 N 1 or cT 3 N 0 without CRM involvement and lateral lymph node metastasis. This study aims to evaluate the efficacy of upfront radical surgery with total mesorectal excision (TME) followed by adjuvant chemotherapy with folinic acid (or leucovorin), fluorouracil, and oxaliplatin (FOLFOX) versus the current standard treatment in patients with surgically resectable, locally advanced rectal cancer., Methods: This study, named TME-FOLFOX, is a prospective, open-label, multicenter, phase II randomized trial. Patients with locally advanced rectal cancer will be randomized to receive PCRT followed by TME and adjuvant chemotherapy (arm A) or upfront radical surgery with TME followed by adjuvant FOLFOX chemotherapy (arm B). Clinical stage II/III rectal cancer without CRM involvement and lateral lymph node metastasis will be defined using preoperative MRI. The primary endpoint is 3-year disease-free survival (DFS). Secondary endpoints include 5-year DFS, local recurrence rate, systemic recurrence rate, cost-effectiveness, and overall survival. We hypothesized that our experimental group (arm B) will have a 3-year DFS of 75% and a non-inferiority margin of 15%., Discussion: Identifying whether patients require PCRT is one of the critical issues in locally advanced rectal cancer. This study aims to elucidate whether PCRT may not be required for all patients with stage II/III rectal cancer, especially for the MRI-based intermediate-risk group (with cT 1-2 N 1 or cT 3 N 0 ) without CRM involvement and lateral lymph node metastasis. If the findings indicate that our proposed treatment, which omits PCRT, is non-inferior to the standard treatment, then patients may avoid unnecessary radiation-related toxicity, have a shorter treatment duration, and save on medical costs., Trial Registration: ClinicalTrials.gov, NCT02167321. Registered on 19 June 2014.

Purpose: We evaluated the role of oxaliplatin as adjuvant chemotherapy in patients with rectal cancer who received preoperative chemoradiotherapy (CRT) with fluoropyrimidine monotherapy and total mesorectal excision (TME)., Methods: The ADORE trial (adjuvant oxaliplatin in rectal cancer) is a multicenter, randomized trial in patients with postoperative ypStage II (ypT3-4N0) or III (ypT any N1-2) rectal cancer after fluoropyrimidine-based preoperative CRT and TME. Patients were randomly assigned (1:1) to receive adjuvant chemotherapy either with FL (fluorouracil 380 mg/m 2 and leucovorin 20 mg/m 2 ) or FOLFOX (oxaliplatin 85 mg/m 2 , leucovorin 200 mg/m 2 , and fluorouracil bolus 400 mg/m 2 on day 1, fluorouracil infusion 2,400 mg/m 2 for 46 hours). Stratification factors included ypStage and participating center. Primary end point was disease-free survival (DFS)., Results: A total of 321 patients were enrolled between November 19, 2008, and June 12, 2012. Six-year DFS rates were 68.2% in the FOLFOX arm versus 56.8% in the FL arm, with a stratified hazard ratio of 0.63 (95% CI, 0.43 to 0.93; P = .018) by intention-to-treat analysis. In the subgroup analysis for DFS, FOLFOX was favorable versus FL in patients with ypStage III, ypN1b, ypN2, high-grade histology, minimally regressed tumor, and an absence of lymphovascular or perineural invasion. Six-year overall survival rate was 78.1% in the FOLFOX arm versus76.4% in the FL arm (hazard ratio, 0.73; 95% CI, 0.45 to 1.19; P = .21). In the subgroup analysis for OS, FOLFOX was favorable versus FL in patients with ypN2 and minimally regressed tumor., Conclusion: Adjuvant FOLFOX improved DFS in patients with rectal cancer with ypStage II and III disease after preoperative CRT. Adjuvant FOLFOX may be considered on the basis of the postoperative pathologic stage in those who received preoperative CRT and TME.

Objectives: To evaluate the diagnostic value of signal intensity (SI)-selected volumetry findings in T2-weighted magnetic resonance imaging (MRI) as a potential biomarker for predicting pathological complete response (pCR) to preoperative chemoradiotherapy (CRT) in patients with rectal cancer., Methods: Forty consecutive patients with pCR after preoperative CRT were compared with 80 age- and sex-matched non-pCR patients in a case-control study. SI-selected tumor volume was measured on post-CRT T2-weighted MRI, which included voxels of the treated tumor exceeding the SI (obturator internus muscle SI + [ischiorectal fossa fat SI - obturator internus muscle SI] × 0.2). Three blinded readers independently rated five-point pCR confidence scores and compared the diagnostic outcome with SI-selected volumetry findings. The SI-selected volumetry protocol was validated in 30 additional rectal cancer patients., Results: The area under the receiver-operating characteristic curve (AUC) of SI-selected volumetry for pCR prediction was 0.831, with an optimal cutoff value of 649.6 mm 3 (sensitivity 0.850, specificity 0.725). The AUC of the SI-selected tumor volume was significantly greater than the pooled AUC of readers (0.707, p < 0.001). At this cutoff, the validation trial yielded an accuracy of 0.87., Conclusion: SI-selected volumetry in post-CRT T2-weighted MRI can help predict pCR after preoperative CRT in patients with rectal cancer., Key Points: • Fibrosis and viable tumor MRI signal intensities (SIs) are difficult to distinguish. • T2 SI-selected volumetry yields high diagnostic performance for assessing pathological complete response. • T2 SI-selected volumetry is significantly more accurate than readers and non-SI-selected volumetry. • Post-chemoradiation therapy T2-weighted MRI SI-selected volumetry facilitates prediction of pathological complete response.

Purpose: Preoperative chemoradiation therapy (CRT) followed by total mesorectal excision (TME) in locally advanced rectal cancer is the standard of care. To date, the role of consolidation chemotherapy after CRT has rarely been addressed through randomized trials. This study aimed to evaluate the efficacy of CRT followed by consolidation chemotherapy compared with CRT alone., Methods and Materials: This study enrolled patients with adenocarcinoma of the rectum and cT3 or cT4 disease with any N category and no metastasis. In arm A (control arm), we planned CRT (50.4 Gy in 28 fractions) with capecitabine followed by TME. In arm B, 2 cycles of capecitabine and oxaliplatin were administered 1 week after the completion of CRT before TME (capecitabine, 1700 mg/m 2 per day from day 1 to 14, and oxaliplatin, 100 mg/m 2 on day 1, every 3 weeks). The downstaging rate (the proportion of ypT0 to ypT2 and ypN0M0) was the primary endpoint, which was to be tested with a 1-sided type I error of 15% and with 85% power., Results: From September 2014 to February 2016, 110 patients (56 in arm A and 54 in arm B) were randomized and 108 (55 in arm A and 53 in arm B) started CRT. TME was conducted per protocol in 96 patients (52 in arm A and 44 in arm B). In arms A and B, downstaging was achieved in 21.2% and 36.4% (P = .077), respectively, and the pathologic complete response rate was 5.8% and 13.6% (P = .167), respectively. Grade ≥3 adverse events occurred in 3.6% of patients in arm A and 9.4% of patients in arm B during the preoperative treatment phase and in 1.9% and 9.0%, respectively, during the postoperative recovery phase., Conclusions: Consolidation chemotherapy with 2 cycles of capecitabine and oxaliplatin demonstrated a marginal improvement in the downstaging rate. However, a phase 3 trial of this strategy is discouraged because of the high dropout rate and safety issues., (Copyright © 2018. Published by Elsevier Inc.)

Purpose: Patterns of locoregional rectal cancer recurrences following total mesorectal excision (TME) were analyzed to define the irradiation volume, especially the lateral pelvic lymph node (LPLN)., Materials and Methods: Of 1243 patients who underwent TME without pelvic radiotherapy between 2005 and 2012, the data of 826 patients with rectal adenocarcinoma without distant metastases were analyzed for relapse patterns, categorized as distant and locoregional (anastomosis, mesorectum, presacral area, and LPLNs) failure., Results: The median follow-up was 61.8 months. The 5-year local recurrence-free, distant metastasis-free, overall survival rates were 88, 82, and 89%, respectively. Relapse occurred in 108 (13%) patients: 90 (11%) had distant and 28 (3%) had locoregional failure. Eight patients had LPLN recurrence: the 2 recurrences from upper rectal cancers occurred near the bifurcation of the common iliac artery into the external and internal iliac vessels; the 6 mid-lower rectal cancers had 16 recurrences near the internal iliac and obturator arteries-five occurred anterior to the obturator artery and posterior to the external iliac artery, superior to the femoral head. LPLN recurrence was associated with pN2 stage, perinodal extension, and lymphovascular invasion., Conclusion: The LPLN component of pre- or postoperative irradiation volumes could potentially be optimized based on our mapping data. However, since patients in our institution at high risk for relapse received either preoperative or postoperative chemoradiation, further analyses are needed to confirm our findings.

Background: We aimed to explore the clinical benefit of adjuvant chemotherapy (AC) with fluoropyrimidine in patients with ypT0-3N0 rectal cancer after preoperative chemoradiation therapy (CRT) followed by total mesorectal excision (TME)., Methods: Patients with ypT0-3N0 rectal cancer after preoperative CRT and TME were included using prospectively collected tumor registry cohort between January 2001 and December 2013. Patients were categorized into two groups according to the receipt of AC. Disease-free survival (DFS) and overall survival (OS) were compared between the adjuvant and observation groups. To control for potential confounding factors, we also calculated propensity scores and performed propensity score-matched analysis for DFS and OS., Results: Of the 339 evaluated patients, 87 patients (25.7%) did not receive AC. There were no differences in DFS (hazard ratio [HR], 0.921; 95% confidence interval [CI], 0.562-1.507; P = 0.742) and OS (HR, 0.835; 95% CI, 0.423-1.648; P = 0.603) between the adjuvant and observation groups. After propensity score matching, DFS (HR, 1.129; 95% CI, 0.626-2.035; P = 0.688) and OS (HR, 1.200; 95% CI, 0.539-2.669; P = 0.655) did not differ between the adjuvant and observation groups. Advanced T stage and positive resection margin were independently associated with inferior DFS and OS on multivariate analysis., Conclusions: AC did not improve DFS and OS for patients with ypT0-3N0 rectal cancer after preoperative CRT followed by TME in this cohort study. The confirmative role of AC in locally advanced rectal cancer should be evaluated in prospective randomized trials with a larger sample size.

The aim of this study was to report the clinical results of reduced pelvic field radiotherapy (RT), excluding the anastomotic site, after total mesorectal excision in selected patients with rectal cancer. Between 2011 and 2014, 99 patients underwent upfront surgery for clinically less-advanced tumors but were finally diagnosed as pT3/N+. Among them, 50 patients with mid-upper rectal cancer who received postoperative RT with a reduced pelvic field were included in this retrospective review. This group was composed of patients with high seated tumors, complete resection with a clear circumferential resection margin, and no complication during surgery. We investigated treatment outcomes, toxicity and the effect of RT-field reduction on organs-at risk in 5 randomly selected patients. During the median follow-up period of 42 months (range: 15-59 months), tumors recurred in 9 patients (18%). The 3-year overall and disease-free survival were 98% and 81%, respectively. Distant metastasis was the dominant failure pattern (n = 8, 16%), while no recurrences occurred at or near anastomotic sites. No anastomotic complications were found on pelvic examination, images and/or colonoscopy. Reported acute and late RT-related toxicities were mostly mild to moderate, with only small numbers of Grade 3 toxicities. None of the patients developed Grade 4-5 acute or late toxicity. With a caudally reduced field, 64% reduction in absolute anastomotic exposure at the maximum dose was achieved compared with the traditional whole-pelvic field (P = 0.008). The reduced pelvic field RT was able to minimize late anastomotic complication without increasing its recurrence in selected patients with mid-upper rectal cancer in the postoperative setting., (© The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.)

Background: Numerous molecular markers have been investigated to predict tumor response after preoperative chemoradiotherapy for rectal cancer., Objective: This study aimed to evaluate the predictive value of biomarkers for the prediction of tumor response after preoperative chemoradiotherapy., Design & Setting: Tumor specimens have been collected prospectively from 80 patients with rectal cancer who underwent curative resection at 8 weeks after completing preoperative chemoradiotherapy., Main Outcome Measures: With the use of reverse transcriptase polymerase chain reaction analysis, mRNA expression levels of 7 candidate biomarkers (p53, p21, Ki-67, VEGF, CD133, CD24, and CD44) were evaluated from fresh tumor samples collected before preoperative chemoradiotherapy. The correlation between biomarker expression levels and the pathologic response was assessed based on histopathological staging (pTNM) and tumor regression grade., Results: The mRNA expression levels of 4 biomarkers (p53, p21, Ki67, and CD133) significantly correlated with tumor regression grade response and pathologic complete response. Patients showing low expression of p53 and/or high expression of p21, Ki67, and CD133 exhibited a significantly greater tumor regression grade response and pathologic complete response rate. A scoring system devised so that 1 point was given for each biomarker whose expression level correlated with pathologic complete response (score range: 0-4) showed that 9 of 62 patients with scores of 0 to 2 achieved pathologic complete response, whereas 15 of 18 patients with scores of 3 to 4 achieved pathologic complete response (14.5% vs 83.3%, p < 0.001). For prediction of pathologic complete response, the scoring system showed 62.5% sensitivity, 94.6% specificity, an 83.3% positive predictive value, and an 85.5% negative predictive value., Limitations: Small patient numbers have limitations related to the reproducibility and ability to provide quantitative information. In addition, this study lacks test and validation sets., Conclusions: The pretreatment mRNA expression levels of 4 biomarkers correlated with pathologic tumor response after intraoperative chemoradiotherapy in rectal cancer. Furthermore, the scoring system combining values of biomarker expression might have predictive power with high positive and negative predictive values.

Purpose/objective(s): Optimal treatment for locally advanced rectal cancer (LARC) with distant metastasis remains elusive. We aimed to evaluate upfront systemic chemotherapy and short-course radiotherapy (RT) followed by delayed surgery for such patients, and to identify favorable prognostic factors., Materials/methods: We retrospectively reviewed 50 LARC patients (cT4 or cT3, <2 mm from the mesorectal fascia) with synchronous metastatic disease. The primary endpoint was progression-free survival (PFS). The secondary endpoints were overall survival, treatment-related toxicity, and compliance. We considered P values <0.05 significant., Results: At 22 months median follow-up, the median PFS time was 16 months and the 2-year PFS rate was 34.8%. Thirty-five patients who received radical surgery for primary and metastatic tumors were designated the curable group. Six patients with clinical complete response (ypCR) of metastases who underwent radical surgery for only the primary tumor were classified as potentially curable. Nine patients who received no radical surgery (3 received palliative surgery) were deemed the palliative group. The ypCR rate among surgery patients was 13.6%. PFS rates for the curable or potentially curable groups were significantly longer than that of the palliative group (P<0.001). On multivariate analysis, solitary organ metastasis and R0 status were independent prognostic factors for PFS., Conclusions: These findings demonstrated that a strong possibility that upfront chemotherapy and short-course RT with delayed surgery are an effective alternative treatment for LARC with potentially resectable distant metastasis, owing to achievement of pathologic down-staging, R0 resection, and favorable compliance and toxicity, despite the long treatment duration.

Objective: To identify patients who are at a higher risk of pathologic circumferential resection margin involvement using preoperative magnetic resonance imaging., Methods: Between October 2008 and November 2012, 165 patients with locally advanced rectal cancer (cT4 or cT3 with <2 mm distance from tumour to mesorectal fascia) who received preoperative chemoradiotherapy were analysed. The morphologic patterns on post-chemoradiotherapy magnetic resonance imaging were categorized into five patterns from Pattern A (most-likely negative pathologic circumferential resection margin) to Pattern E (most-likely positive pathologic circumferential resection margin). In addition, the location of mesorectal fascia involvement was classified as lateral, posterior and anterior. The diagnostic accuracy of the morphologic criteria was calculated using receiver operating characteristic curve analysis., Results: Pathologic circumferential resection margin involvement was identified in 17 patients (10.3%). The diagnostic accuracy of predicting pathologic circumferential resection margin involvement was 0.73 using the five-scale magnetic resonance imaging pattern. The sensitivity, specificity, positive predictive value and negative predictive value for predicting pathologic circumferential resection margin involvement were 76.5, 65.5, 20.3 and 96.0%, respectively, when cut-off was set between Patterns C and D. On multivariate logistic regression, the magnetic resonance imaging patterns D and E (P= 0.005) and posterior or lateral mesorectal fascia involvement (P= 0.017) were independently associated with increased probability of pathologic circumferential resection margin involvement. The rate of pathologic circumferential resection margin involvement was 30.0% when the patient had Pattern D or E with posterior or lateral mesorectal fascia involvement., Conclusions: Patients who are at a higher risk of pathologic circumferential resection margin involvement can be identified using preoperative magnetic resonance imaging although the predictability is moderate., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background and Purpose: To evaluate the efficacy and safety of upfront mFOLFOX6 followed by short-course radiotherapy (SCRT) and surgery in patients with locally advanced rectal cancer and liver-only metastases., Materials and Methods: This single-arm phase II study involved 32 patients. mFOLFOX6 was administered for four cycles followed by SCRT and another four cycles of mFOLFOX6. Surgery was performed 4-6 weeks after the last chemotherapy cycle. The primary endpoint was complete (R0) resection rate. Secondary endpoints were response rate, progression-free survival (PFS), overall survival (OS), and complication rates., Results: Surgical resection of the rectum and liver was performed in 25 patients (78%) and R0 resection was achieved in 20 patients (63%). Local tumor downstaging was observed in 54% of patients. Median OS and PFS were 38 and 9 months, respectively. One patient discontinued treatment due to toxicity and no treatment-related deaths occurred. Patients who progressed after 4 cycles of mFOLFOX6 were less likely to receive resection., Conclusions: This regimen was safe and effective in inducing local tumor response and achieving R0 resection in this patient population., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Purpose: Rectal cancer patients achieving pCR are known to have an excellent prognosis, yet no widely accepted consensus on risk stratification and post-operative management (e.g., adjuvant therapy) has been established. This study aimed to identify magnetic resonance imaging (MRI) high-risk factors for tumor relapse in pathological complete remission (pCR) achieved by rectal cancer patients who have undergone neoadjuvant concurrent chemoradiation therapy (CRT) and curative resection., Materials and Methods: We analyzed 88 (male/female = 55/33, median age, 59.5 years [range 34-78]) pCR-proven rectal cancer patients who had undergone pre-CRT MRI, CRT, post-CRT MRI and curative surgery between July 2005 and December 2012. Patients were observed for post-operative tumor relapse. We analyzed the pre/post-CRT MRIs for parameters including mrT stage, mesorectal fascia (mrMRF) status, tumor volume, tumor regression grade (mrTRG), nodal status (mrN), and extramural vessel invasion (mrEMVI). We performed univariate analysis and Kaplan-Meier survival analysis., Results: Post-operative tumor relapse occurred in seven patients (8.0%, n = 7/88) between 5.7 and 50.7 (median 16.8) months. No significant relevance was observed between tumor volume, volume reduction rate, mrTRG, mrT, or mrN status. Meanwhile, positive mrMRF (Ppre-CRT = 0.018, Ppre/post-CRT = 0.006) and mrEMVI (Ppre-CRT = 0.026, Ppre-/post-CRT = 0.008) were associated with higher incidence of post-operative tumor relapse. Kaplan-Meier survival analysis revealed a higher risk of tumor relapse in patients with positive mrMRF (Ppre-CRT = 0.029, Ppre-/post-CRT = 0.009) or mrEMVI (Ppre-CRT = 0.024, Ppre-/post-CRT = 0.003)., Conclusion: Positive mrMRF and mrEMVI status was associated with a higher risk of post-operative tumor relapse of pCR achieved by rectal cancer patients, and therefore, can be applied for risk stratification and to individualize treatment plans.

Purpose: The purpose of this study was to evaluate the rate of pathologic complete response (pCR) in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiation therapy (CRT) with leucovorin (FL) versus irinotecan/S-1 (IS)., Methods and Materials: Patients with resectable LARC (clinical stage T3/4, lymph node positive, or both) were randomly assigned to receive preoperative radiation (45-50.4 Gy in 25 to 28 daily fractions) and concomitant chemotherapy either with a bolus injection of FL (400 mg/m(2)/day 5-fluorouracil and 20 mg/m(2)/day leucovorin) for 3 consecutive days every 4 weeks for 2 cycles (FL group) or with 40 mg/m(2) irinotecan on days 1, 8, 15, 22, and 29, and 35 mg/m(2) S-1 twice on the day of irradiation (IS group). Curative surgery was performed approximately 4 to 8 weeks after the completion of CRT. The postoperative chemotherapy regimen was FL with a primary endpoint of a pCR rate evaluation., Results: One hundred forty-two eligible patients were randomly assigned, and the median follow-up duration was 43.8 months (95% confidence interval, 40.8-46.8 months). One hundred thirty-three patients (93.7%) of 142 underwent total mesorectal excision; pCR was achieved in 11 (16.7%) of 66 patients in the FL group and 17 (25.8%) of 67 patients in the IS group (P=.246). When good responders were defined as patients with Mandard grades 1 and 2, the rate of good responders was significantly higher in the IS group than in the FL group (54.6% vs 36.4%, respectively, P=.036). The preoperative rates of grade 3 and 4 toxicities were higher in the IS group (7.0%) than in the FL group (1.4%, P=.095). The 3-year disease-free survival was not significantly different between the 2 groups (79.7% vs 76.6%, respectively, P=.896)., Conclusions: IS-based preoperative CRT did not increase pCR rate, but it did increase acute toxicities compared with standard 5-FU treatment. Therefore, further investigation is needed., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: The role of adjuvant chemotherapy for patients with rectal cancer is controversial, especially when used after preoperative chemoradiotherapy. Fluoropyrimidine-based adjuvant chemotherapy, including fluorouracil and leucovorin, has been widely used; however, the addition of oxaliplatin to fluorouracil and leucovorin (FOLFOX), a standard adjuvant regimen for colon cancer, has not been tested in rectal cancer. We aimed to compare the efficacy and safety of adjuvant fluorouracil and leucovorin with that of FOLFOX in patients with locally advanced rectal cancer after preoperative chemoradiotherapy., Methods: In this open-label, multicentre, phase 2, randomised trial, patients with postoperative pathological stage II (ypT3-4N0) or III (ypTanyN1-2) rectal cancer after preoperative fluoropyrimidine-based chemoradiotherapy and total mesorectal excision were recruited and randomly assigned (1:1) via a web-based software platform to receive adjuvant chemotherapy with either four cycles of fluorouracil and leucovorin (fluorouracil 380 mg/m(2) and leucovorin 20 mg/m(2) on days 1-5, every 4 weeks) or eight cycles of FOLFOX (oxaliplatin 85 mg/m(2), leucovorin 200 mg/m(2), and fluorouracil bolus 400 mg/m(2) on day 1, and fluorouracil infusion 2400 mg/m(2) for 46 h, every 2 weeks). Stratification factors were pathological stage (II vs III) and centre. Neither patients nor investigators were masked to group assignment. The primary endpoint was 3-year disease-free survival, analysed by intention to treat. This study is fully enrolled, is in long-term follow-up, and is registered with ClinicalTrials.gov, number NCT00807911., Findings: Between Nov 19, 2008, and June 12, 2012, 321 patients were randomly assigned to fluorouracil and leucovorin (n=161) and FOLFOX (n=160). 141 (95%) of 149 patients in the fluorouracil plus leucovorin group and 141 (97%) of 146 in the FOLFOX group completed all planned cycles of adjuvant treatment. Median follow-up was 38·2 months (IQR 26·4-50·6). 3-year disease-free survival was 71·6% (95% CI 64·6-78·6) in the FOLFOX group and 62·9% (55·4-70·4) in the fluorouracil plus leucovorin group (hazard ratio 0·657, 95% CI 0·434-0·994; p=0·047). Any grade neutropenia, thrombocytopenia, fatigue, nausea, and sensory neuropathy were significantly more common in the FOLFOX group than in the fluorouracil plus leucovorin group; however, we noted no significant difference in the frequency of these events at grade 3 or 4. The most common grade 3 or worse adverse events were neutropenia (38 [26%] of 149 patients in the fluorouracil plus leucovorin group vs 52 [36%] of 146 patients in the FOLFOX group), leucopenia (eight [5%] vs 12 [8%]), febrile neutropenia (four [3%] vs one [<1%]), diarrhoea (four [3%] vs two [1%]), and nausea (one [<1%] vs two [1%])., Interpretation: Adjuvant FOLFOX improves disease-free survival compared with fluorouracil plus leucovorin in patients with locally advanced rectal cancer after preoperative chemoradiotherapy and total mesorectal excision, and warrants further investigation., Funding: Korea Healthcare Technology R&D Project (South Korean Ministry of Health and Welfare)., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: Numerous molecular markers have been investigated as potential predictors of tumor responses to preoperative chemoradiotherapy (preCRT) for rectal cancer., Objective: To develop a system in which biomarkers are used to predict the likelihood of a pathologic complete response (pCR) to preCRT., Design & Setting: This is a retrospective analysis of tumor specimens collected prior to preCRT from 81 patients who underwent curative resection for primary rectal adenocarcinoma between June 2008 and February 2012., Main Outcome Measures: Using tissue microarrays and immunohistochemistry, expression levels of twelve candidate biomarkers (p53, p21, Bcl2, Bax, EGFR, Cox-2, MLH-1, MSH-2, Ku70, VEGF, TS, Ki-67) were evaluated in paraffin-embedded tumor samples collected before preCRT. The correlation between biomarker expression levels and the pathologic response to preCRT was assessed based on histopathological staging (pTNM) and tumor regression grade (TRG)., Results: Expression levels of 4 biomarkers (p53, VEGF, p21, Ki67) correlated with pCR. Patients showing low expression of p53 and/or high expression of VEGF, p21, and Ki67 exhibited a significantly greater pCR rate. A scoring system devised so that one point was given for each biomarker whose expression level correlated with pCR (score range: 0-4) showed that 1 of 26 patients with scores of 0 to 1 achieved pCR, whereas 26 of 55 patients with scores of 2 to 4 achieved pCR (3.8% vs. 47.3%, p < 0.001). For prediction of pCR, the scoring system showed 96.3% sensitivity, 46.3% specificity, a 47.3% positive predictive value, and a 96.2% negative predictive value., Limitations: Immunohistochemistry has limitations related to reproducibility and the ability to provide quantitative information. In addition, this study lacks test and validation sets., Conclusions: Expression levels of 4 biomarkers correlated with pCR after preCRT for rectal cancer. A scoring system based on levels of biomarker expression showed good sensitivity and negative predictive value for pCR.

Purpose: To investigate the role of biomarkers including serum tissue inhibitor of metalloproteinases-1 (TIMP-1), urokinase plasminogen activator receptor, vascular endothelial growth factor, and epidermal growth factor receptor in predicting pathologic response to neoadjuvant chemoradiation (NACRT) for rectal cancer., Methods: Between 2007 and 2009, 50 clinical TNM stage II or III patients were analyzed in this prospective study. Pre- and post-NACRT serum levels of biomarkers were assessed using ELISAs. The primary and secondary endpoints were pathologic complete response (pCR) and Mandard regression grade (MRG)., Results: The pCR was reported in 5 patients (10.0%). According to the MRG, fifteen patients (30.0%) were divided into group A (Grade I-II), the others in group B (Grade III-V). On univariate analysis, post-NACRT TIMP-1 showed notable significance with pCR (P = 0.092) and significant correlation with MRG group A (P = 0.003). Post-NACRT TIMP-1 ≤ 204.5 ng/mL as cut-off value by ROC curve was associated with more pCR and MRG group A patients (P = 0.016 and 0.002). Interval between NACRT and surgery was related to pCR with approached trend levels of significance (P = 0.05) and to MRG group A significantly on univariate analysis of clinical factors (P = 0.031). On multivariate analysis, post-NACRT TIMP-1 was not significantly related to pCR (P = 0.187), while it was significantly associated with MRG (P = 0.009). Among clinical responders, post-NACRT TIMP-1 level ≤ 204.5 ng/mL was significantly associated with pCR (P = 0.021) and MRG group A (P = 0.003)., Conclusions: Post-NACRT serum TIMP-1 could be used as a predictive marker of pathologic response to NACRT in rectal cancer, even in patients with clinical response.

Purpose: The outcomes of adjuvant chemoradiation for locally advanced rectal cancer are nonuniform among patients with matching prognostic factors. We explored the role of molecular markers for predicting the outcome of adjuvant chemoradiation for rectal cancer patients., Methods and Materials: The study included 68 patients with stages II to III rectal adenocarcinoma who were treated with total mesorectal excision and adjuvant chemoradiation. Chemotherapy based on 5-fluorouracil and leucovorin was intravenously administered each month for 6-12 cycles. Radiation therapy consisted of 54 Gy delivered in 30 fractions. Immunostaining of surgical specimens for COX-2, EGFR, VEGF, thymidine synthase (TS), and Raf kinase inhibitor protein (RKIP) was performed., Results: The median follow-up was 65 months. Eight locoregional (11.8%) and 13 distant (19.1%) recurrences occurred. Five-year locoregional failure-free survival (LRFFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) rates for all patients were 83.9%, 78.7%, 66.7%, and 73.8%, respectively. LRFFS was not correlated with TNM stage, surgical margin, or any of the molecular markers. VEGF overexpression was significantly correlated with decreased DMFS (P=.045), while RKIP-positive results were correlated with increased DMFS (P=.025). In multivariate analyses, positive findings for COX-2 (COX-2+) and VEGF (VEGF+) and negative findings for RKIP (RKIP-) were independent prognostic factors for DMFS, DFS, and OS (P=.035, .014, and .007 for DMFS; .021, .010, and <.0001 for DFS; and .004, .012, and .001 for OS). The combination of both COX-2+ and VEGF+ (COX-2+/VEGF+) showed a strong correlation with decreased DFS (P=.007), and the combinations of RKIP+/COX-2- and RKIP+/VEGF- showed strong correlations with improved DFS compared with the rest of the patients (P=.001 and <.0001, respectively)., Conclusions: Molecular markers can be valuable in predicting treatment outcome of adjuvant chemoradiation for rectal cancer patients., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Choosing the most effective approach for treating rectal cancer with mesorectal fascia (MRF) involvement or closeness and synchronous distant metastases is a current clinical challenge. The aim of this retrospective study was to determine if upfront systemic chemotherapy and short-course radiotherapy (RT) with delayed surgery enables R0 resection., Methods: Between March 2009 and October 2009, six patients were selected for upfront chemotherapy and short-course RT (5 × 5 Gy) with delayed surgery. The patients had locally advanced primary tumors with MRF involvement or closeness, as well as synchronous and potentially resectable distant metastases. Chemotherapy was administered to five patients between the end of the RT and surgery. All patients underwent total mesorectal excision (TME)., Results: The median patient age was 54 years (range 39-63). All primary and metastatic lesions were resected simultaneously. The median duration between short-course RT and surgery was 13 weeks (range, 7-18). R0 resection of rectal lesions was achieved in 5 patients. One patient, who had a very low-lying tumor, had an R1 resection. The median follow-up duration for all patients was 16.7 months (range, 15.5-23.5). One patient developed liver metastasis at 15.7 months. There have been no local recurrences or deaths., Conclusions: Upfront chemotherapy and short course RT with delayed surgery is a valuable alternative treatment approach for patients with MRF involvement or closeness of rectal cancer with distant metastases.

Purpose: The benefit of adjuvant radiotherapy in patients with stage IIA (T3N0) rectal cancer following total mesorectal excision (TME) is controversial. We evaluated the effect of adjuvant chemoradiotherapy (CRT) versus chemotherapy (CT) alone on the local recurrence and survival of patients with stage IIA rectal cancer after TME., Methods: Between 1996 and 2004, patients with stage IIA rectal cancer who received adjuvant CT (n = 29) or CRT (n = 122) following TME were enrolled. Oncologic outcomes were compared between groups, and risk factors for local recurrence and overall survival rates were analyzed., Results: The median follow-up period was 78 months. No significant differences were observed in the 5-year local recurrence (3.4% versus 9.0%; P = 0.348) or 5-year overall survival rates (86.2% versus 80.3%; P = 0.924) between CT and CRT. However, involvement of the circumferential resection margin and age >60 years were associated with adverse oncologic outcomes., Conclusions: Additional postoperative radiotherapy did not alter local recurrence or survival after TME in patients with stage IIA rectal cancer. Postoperative radiation may be an overtreatment as an adjuvant therapy in patients with stage IIA rectal cancer if they had no other risk factors. However, randomized controlled trials are warranted to confirm this suggestion.

Background: Synchronous liver metastases are detected in approximately 25% of colorectal cancer patients at diagnosis. The rates of local failure and distant metastasis are substantial in these patients, even after undergoing aggressive treatments including resection of primary and metastatic liver tumors. The purpose of this study was to determine whether adjuvant pelvic radiotherapy is beneficial for pelvic control and overall survival in rectal cancer patients with synchronous liver metastasis after primary tumor resection., Methods: Among rectal cancer patients who received total mesorectal excision (TME) between 1997 and 2006 at Yonsei University Health System, eighty-nine patients diagnosed with synchronous liver metastasis were reviewed. Twenty-seven patients received adjuvant pelvic RT (group S + R), and sixty-two patients were managed without RT (group S). Thirty-six patients (58%) in group S and twenty patients (74%) in group S+R received local treatment for liver metastasis. Failure patterns and survival outcomes were analyzed., Results: Pelvic failure was observed in twenty-five patients; twenty-one patients in group S (34%), and four patients in group S+R (15%) (p = 0.066). The two-year pelvic failure-free survival rates (PFFS) of group S and group S+R were 64.8% and 80.8% (p = 0.028), respectively, and the two-year overall survival rates (OS) were 49.1% and 70.4% (p = 0.116), respectively. In a subgroup analysis of fifty-six patients who received local treatment for liver metastasis, the two-year PFFS were 64.9% and 82.9% (p = 0.05), respectively; the two-year OS were 74.1% and 80.0% (p = 0.616) in group S (n = 36) and group S+R (n = 20), respectively., Conclusions: Adjuvant pelvic RT significantly reduced the pelvic failure rate but its influence on overall survival was unclear. Rectal cancer patients with synchronous liver metastasis may benefit from adjuvant pelvic RT through an increased pelvic control rate and improved quality of life.

Background and Purpose: The aim of this study is to evaluate the efficacy and safety of preoperative radiation therapy combined with S-1 and irinotecan (SI) in LARC., Materials and Methods: Patients were considered LARC if they had a T3/T4 lesion or node positive. Weekly doses of 40 mg/m(2) irinotecan were intravenously administered once per week during weeks 1-5 of radiotherapy. S-1 (70 mg/m(2)) was given from Monday to Friday in all weeks of radiotherapy. 3-D conformal radiotherapy was given at daily fractions of 1.8Gy for 5days for a total dose of 50.4 (45+5.4)Gy. Surgery was performed 4-6 weeks following the completion of chemoradiation., Results: Between June 2006 and November 2007, 43 pts were enrolled. The stage was: cT3 24 patients, cT4 6 patients; 28 patients were cN+. Forty-one patients completed the chemoradiation and 42 patients underwent operation: a low anterior resection was performed in 36 patients, a total colectomy in 1 patient, and an abdominal perineal resection in 5 patients. T downstaging was observed in 50%; 23 N+ patients became N- (55%). The complete pathological response was observed in 9 patients (21%). The 3-year locoregional failure rate, distant failure rate, disease-free survival, and overall survival were 9.5%, 18.6%, 72.1%, and 94.3%, respectively. Only three patients experienced G3 diarrhea; one had G3 sepsis and two had septic shock. Hematological toxicity (G3-G4) was observed in five patients., Conclusions: This study demonstrated the efficacy of preoperative CRT with S-1 and irinotecan with 21% of complete response. However, prompt recognition and management of infection is needed to use it in patients with locally advanced rectal cancer., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

Background: Over the past several years, preoperative chemoradiotherapy (CRT) has contributed remarkably to make more sphincter-preserving procedure (SPP) possible for lower rectal cancer. The aim of this study was to compare the outcomes between abdominoperineal resection (APR) and SPP after preoperative CRT in patients with locally advanced lower rectal cancer., Methods: A retrospective investigation was conducted with a total of 122 patients who underwent radical surgery combined with preoperative CRT for locally advanced lower rectal cancer. Of these, 50 patients underwent APR and 72 received SPP. Surgery was performed 6-8 weeks after completion of preoperative CRT. Oncologic outcomes were compared between the two groups, and the clinicopathologic factors affecting the treatment outcomes were evaluated., Results: Circumferential resection margin (CRM) involvement (P = 0.037) and postoperative complication rate (P = 0.032) were significantly different between APR and SPP. Patients who underwent APR had a higher 5-year local recurrence (22.0% vs. 11.5%, P = 0.028) and lower 5-year cancer-specific survival (52.9% vs. 71.1%, P = 0.03) rate than those who underwent SPP. Pathologic N stage was the most critical predictor for local recurrence and survival., Conclusions: Our study shows that APR following preoperative CRT exhibited more adverse oncologic outcomes compared with SPP. This result may be due to higher rates of CRM involvement in APR even with preoperative CRT. We suggest that sharp perineal dissection and wider cylindrical excision at the level of the anorectal junction are required to avoid CRM involvement and improve oncologic outcomes in patients who undergo APR following preoperative CRT.

S-1 is a novel, oral fluoropyrimidine and a known radiosensitizer. We conducted a phase I trial to establish a schedule of S-1/irinotecan with standard pelvic radiotherapy as a preoperative treatment of locally advanced rectal cancer. Our findings suggest that this new combination is feasible and well tolerable.

Background: The da Vinci system is a newly developed device for colorectal surgery, therefore experience of its use for rectal cancer surgery is limited and there are no reports describing the use of four robotic arms with this system. The aim of this study is to evaluate the safety and feasibility of the four-arm da Vinci system for total mesorectal excision in rectal cancer patients., Methods: Clinicopathologic data were prospectively collected on nine patients who underwent robotic total mesorectal excision using four robotic arms for the treatment of mid or low rectal cancer between November 2006 and Febuary 2007. Patient demographics, perioperative clinical outcomes, and pathology results with macroscopic grading (complete, nearly complete, incomplete) were evaluated., Results: nine patients with mid or low rectal cancer underwent robotic total mesorectal excison using four robotic arms without serious complications. The mean length of hospital stay was 7.4 +/- 1.3 days (range 5.0-10.0 days) and the mean operating time was 220.8 +/- 49.4 min (range 153-315 min). Macroscopic grading of the specimen was complete in eight patients and nearly complete in one patient. There were no cases of conversion., Conclusion: In the present study, we accomplished nine robot-assisted rectal resections safely and effectively.

Until mid-1990s, fluorouracil was the only chemotherapeutic agent available for the treatment of colorectal cancer. The treatment of advanced colorectal cancer has evolved considerably over the last decade. Considerable improvements in survival as well as quality of life have been achieved with the application of oxaliplatin and irinotecan with fluoropyrimidine as a first and subsequent line therapy for colorectal cancer. Development of oral fluoropyrimidines as an alternative to intravenous administration provides an additional option for combination cytotoxic therapy, which is currently being assessed in phase III trials in advanced settings. The appearance of biologic agents in mid-2000s, namely cetuximab and bevacizumab, and their integration with conventional cytotoxic therapy for the treatment of colorectal cancer has additionally expanded the options for the treatment. Their dramatic success has led to further clinical studies of targeted therapy in colorectal cancer, making it one of the most promising areas of cancer research. Although considerable improvement was achieved by incorporating oxaliplatin in adjuvant chemotherapy for the treatment of colon cancer, there has been no phase III trial incorporating new agents in adjuvant setting for rectal cancer. However, many phase II trials on the efficacy of new agents in the setting of concurrent chemoradiation are in progress. Based on their results, randomized phase III clinical trials evaluating new agents in preoperative or postoperative setting will be carried out.

Purpose: To compare the effect of reducing the irradiated small-bowel volume with the use of belly board, bladder distension or both methods combined, in patients with rectal cancer undergoing postoperative pelvic radiotherapy., Patients and Methods: This study enrolled 20 consecutive patients with rectal cancer who were scheduled to receive postoperative pelvic radiotherapy. All patients underwent four sets of CT scans under four different methods as follows: group I: empty bladder without the use of a belly board; group II: empty bladder with the use of a belly board; group III: bladder distension without the use of a belly board; group IV: bladder distension with the use of a belly board. The conventional three-field treatment plan was made using a three-dimensional treatment planning system. The irradiated small-bowel volume was calculated at 10% intervals from 10% to 100% of the prescribed dose., Results: The volume of the irradiated small bowel decreased in the order of group I, group II, group III, and group IV at all dose levels (p < 0.001). In comparison to group I, the mean absolute volume reductions (relative volume reduction) of the irradiated small bowel were 41.5 +/- 20.1 cm(3) (33.9 +/- 12.9%) in group II, 76.6 +/- 30.5 cm(3) (55.1 +/- 17.8%) in group III, and 98.5 +/- 36.7 cm(3) (70.7 +/- 14.5%) in group IV., Conclusion: Bladder distension was a more effective method than the belly board for reducing the irradiated small-bowel volume in postoperative pelvic radiotherapy of rectal cancer patients. The combination of the belly board and bladder distension showed an additive effect and was the most effective method for reducing the irradiated small-bowel volume.

Purpose: We performed magnetic resonance (MR) volumetry before and after neoadjuvant chemoradiation for evaluating response to therapy in T3 and T4 rectal cancer. To investigate the utility of MR volumetry for predicting the response to neoadjuvant chemoradiation, we compared results from MR volumetry before chemoradiation with those after chemoradiation., Methods and Materials: A total 112 patients with T3 or T4 rectal cancer who successfully underwent MR volumetry and completed neoadjuvant chemoradiation followed by radical resection for cure were identified. MR volumetries were performed before and after chemoradiation. We compared pre- and postchemoradiation tumor volume and % volume reduction rates of patients whose tumors were down-staged with those of patients that were not down-staged. The same analyses were also performed between those patients having a complete histologic regression and those with residual disease in the operative specimen. We assessed the difference of % volume reduction rate according to Dworak's rectal cancer regression grades., Results: Fifty-seven patients (50.9%) demonstrated a tumor down-staging after chemoradiation therapy. Both pre- and posttreatment MR tumor volumes were significantly less in patients whose tumors were down-staged than in patients that were not down-staged (p = 0.04, 0.031), and % volume reduction rates were significantly higher in patients whose tumors were down-staged (p = 0.024). Sixteen patients (14.3%) showed pathologically complete tumor regression. The differences of MR tumor volumes before and after chemoradiation and % volume reduction rates were not significantly different between patients having a complete histologic regression and those with residual disease (p = 0.688, 0.451, and 0.480). The differences of % volume reduction rates according to Dworak's grades were statistically significant (p = 0.03)., Conclusion: The MR volumetric examinations before and after chemoradiation demonstrated the significant difference of tumor volume and % volume reduction rate between patients whose tumors were down-staged and those that were not down-staged. The volume reduction rates were significantly different among groups according to Dworak's grades. However, the MR volumetric evaluation could not identify any differences between those patients having a complete histologic regression and those with residual disease.

In an attempt to improve local control and survival in patients with advanced rectal carcinoma, neoadjuvant chemoradiation therapy (CRT) has been increasingly used in patient management. However, a significant proportion of patients shows poor response to adjuvant CRT. Thus, the ability to predict CRT responsiveness in patients with rectal cancer would benefit effective management. Several molecular markers related to regulation of cell cycle, apoptosis, or DNA repair have been proposed as candidate predictors of therapeutic response to CRT, but, to date, none has been definitively proven to be predictive of CRT response. To evaluate the use of various molecular markers as predictors of the response to CRT in rectal carcinoma, we investigated immunohistochemical expressions of p53, p21 WAF1/CIP1 , Bcl-2, Bax, Ki-67, Ku-70, and 2 new candidate markers (histone deacetylase 1 and metabotropic glutamate receptor 4) in pretreatment biopsy samples of 130 rectal carcinomas. We further compared the expressions of these molecular markers with the pathological responses of the tumors after therapy. We found that Bax expression, among the markers studied, was exclusively related to tumor regression. Its expression was significantly higher in the complete response group as compared with the partial response group (54% versus 29%, P = .017). This result confirms that apoptosis plays an important role in tumor response to CRT and provides evidence that Bax may serve as a predictable molecular marker for chemoradiosensitivity in rectal carcinoma.