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Background Anal squamous cell carcinoma (ASCC) is a rare malignant tumor with increasing incidence. The goal of our study was to analyze the treatment outcome and prognostic factors of ASCC in South China in the past half‐century. Methods This study retrospectively included 59 patients with ASCC admitted from 1975 to 2018 in Sun Yat‐sen University cancer center. The clinical records and follow‐up information of all patients were collected. Survival analysis and univariate and multivariate regression analyses were performed using the “survival” and “survminer” packages of R software. Results In 59 patients, 5 patients had distant metastasis at diagnosis. Among 54 M0 stage patients, 33 patients received chemoradiotherapy (CRT), 19 patients received local surgery, and 2 patients refused curative treatment and received the best supportive treatment (BST). The most common grade 3–4 acute toxicities during treatment were myelosuppression and radiation dermatitis. The median follow‐up time was 32 months. For the whole group, the 3‐year and 5‐year overall survival (OS) rates and disease‐free survival (DFS) were 71.1% and 63.6%, and 73.4% and 69.0%, respectively. Multivariate regression analysis showed that the T3–4 stage was an independent prognostic risk factor for OS, progression‐free survival (PFS), and DFS. And M1 was an independent prognostic risk factor for PFS and DFS. Patients in stage M0 mainly treated with CRT had better local control than those mainly treated with surgery (p = 0.027). For M0 patients, induction chemotherapy combined with CRT tends to prolong OS compared with CRT alone (p = 0.26). The 3‐year colostomy‐free survival for the whole group was 81.1%. Conclusions CRT is recommended as the first choice for the treatment of M0 stage ASCC. Induction chemotherapy may bring better survival benefits for some patients. Patients with ASCC in China seem to have a better local control rate, which suggested different treatment strategies may be needed in China., CRT is recommended as the first choice for the treatment of M0 stage ASCC. Induction chemotherapy may bring better survival benefits for some patients. The different failure modes of disease control required different treatment strategies in China.

Ting Jiang,1,* Shuang Liu,1,* Xiaojun Wu,2,* Xiaoqing Liu,3 Weizhan Li,4 Shanfei Yang,1 Peiqiang Cai,5 Shaoyan Xi,6 Zhifan Zeng,1 Yuanhong Gao,1 Gong Chen,2 Weiwei Xiao1 1Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, People’s Republic of China; 2Department of Colorectal Surgery, Sun Yat-Sen University Cancer Center, Guangzhou, People’s Republic of China; 3Department of Radiation Oncology, Guangzhou Concord Cancer Center, Guangzhou, People’s Republic of China; 4Department of Radiation Oncology, Panyu Center Hospital, Guangzhou, People’s Republic of China; 5Department of Radiology, Sun Yat-Sen University Cancer Center, Guangzhou, People’s Republic of China; 6Department of Pathology, Sun Yat-Sen University Cancer Center, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Gong Chen; Weiwei Xiao Email chengong@sysucc.org.cn; xiaoww@sysucc.org.cnPurpose: This study aimed to predict the risks of distant metastasis (DM) of locally advanced rectal cancer (LARC) patients with pathological complete response (pCR) after neoadjuvant chemoradiotherapy (NACRT) and total mesorectal excision (TME), and to find the association between adjuvant chemotherapy (ACT) and their survival outcomes.Methods and Materials: A total of 242 patients with LARC achieving pCR after NACRT were enrolled in this retrospective study. We developed a nomogram model using logistic regression analyses for predicting risk of DM. The model performance was evaluated by the concordance index and calibration curve. Survival was determined using Kaplan–Meier survival curve.Results: Age, pre-operative CEA, pre-treatment CEA and distance of tumor to anal verge were identified as significantly associated variables that could be enrolled in the model to predict the risk of DM for pCR patients. The nomogram we created had a bootstrapped-concordance index of 0.731 (95% CI = 0.627 to 0.834) and was well calibrated. The high risk group was more likely to develop DM than low risk group (total score) (95% CI = 1.439 to 6.493, P = 0.0036). The 1-year, 3-year, and 5-year distant metastasis-free survival (DMFS) for the low and high risk groups (total score ≤ 90 vs > 90) was 97.8%, 94.2%, 94.2% and 91.3%, 83.4%, 81.8%, respectively (P = 0.0036). DM occurred within 1 and 2 years after TME surgery was 33.3% and 55.6% for the low risk group, and 47.3% and 84.2% for the high risk group. The value of ACT was assessed among the whole cohort, patients with cT3-4, with cN+ or with either DM risk group, but no significant difference was observed concerning DMFS whether ACT was given or not (all P > 0.05). Active treatment after DM was more beneficial than palliative treatment (P < 0.001).Conclusion: The nomogram model, including age, pre-operative CEA, pre-treatment CEA and distance to anal verge, predicted the probability of DM among LARC patients achieving pCR after NACRT. The effects of ACT were not seen in different subgroups, while closer clinical follow-up may have greater contribution to pCR patients in the first 2 years, especially for patients with relatively higher risk to develop DM. It is suggested that timely active treatment can bring survival benefit for pCR patients developing DM after NACRT.Keywords: locally advanced rectal cancer; LARC, pathological complete response; pCR, adjuvant chemotherapy; ACT, distant metastasis; DM

Background: The intent of this article is to review the advances in pre-clinical or clinical research probing into the relationship between the gut microbiome and radiation enteritis. Methods: Combinations of keywords with Boolean operators were used to identify relevant documents retrieved from PubMed, MEDLINE, Web of Science, and Google Scholar. Results: A considerable number of studies have shown that the intestinal flora interacts with treatment related side effects. The diversity and composition of gut microbiota prior to radiotherapy are linked to treatment toxicity. Radiotherapy leads to changes in the diversity and abundance of intestinal flora and alters the intestinal flora microenvironment. Conclusions: Dysbiosis caused by radiation increases the bowel’s susceptibility to injury, promotes the occurrence and development of radiation enteritis, ultimately affecting the outcomes of cancer therapy. It requires further exploration and elaboration of the occurrence and progression mechanisms so as to fundamentally reduce the incidence and severity of radiation enteritis.

This study aimed to identify patients who benefit from radical surgery among those with rectal cancer who achieved clinical complete response (cCR). Patients with locally advanced rectal cancer (LARC; stage II/III) who achieved cCR after neoadjuvant chemoradiotherapy (nCRT) were included (n = 212). Univariate/multivariate Cox analysis was performed to validate predictors for distant metastasis‐free survival (DMFS). A decision tree was generated using recursive partitioning analysis (RPA) to categorize patients into different risk stratifications. Total mesorectal excision (TME) was compared with the watch‐and‐wait (W&W) strategy in each risk group. Two molecular predicators of CEA and CA19‐9 were selected to establish the RPA‐based risk stratification, categorizing LARC patients into low‐risk (n = 139; CA19‐9, In total, 212 patients with cCR were retrospectively analyzed and were categorized into low‐risk and high‐risk groups according to their baseline serum concentration of CEA and CA19‐9. Significantly better survival was observed in low‐risk patients when they underwent radical surgery, compared with their counterparts who underwent the watch‐and‐wait strategy.

Su-ping Guo,1,2,* Chen Chen,1,2,* Zhi-fan Zeng,1,2 Qiao-xuan Wang,1,2 Wu Jiang,2,3 Yuan-hong Gao,1,2 Hui Chang1,2 1Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China; 2State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People’s Republic of China; 3Department of Colorectal Surgery, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yuan-hong Gao; Hui ChangDepartment of Radiation Oncology, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, People’s Republic of ChinaTel +86-13560182168; +86-13480295989Email gaoyh@sysucc.org.cn; changhui@sysucc.org.cnBackground: Serum lipids have been reported as prognosticators for malignancies, including rectal cancer (RC). Yet, their value in predicting the response of RC to neoadjuvant chemoradiotherapy (NACRT) remains unknown. This study aimed to assess the predictive abilities of serum lipids for a bad response, and to build a serum lipid-based prediction model.Methods: In total, 751 patients diagnosed with stage cII–III RC and treated with NACRT plus surgery from January 2007 to August 2018 were retrospectively reviewed and randomly divided into two data sets, in a ratio of 1:1. Receiver operating characteristics (ROC) analysis was conducted in the development set to select possible predictors of bad NACRT response from pathoclinical factors, including serum lipids. Multivariate logistic regression was conducted to further determine independent predictors, which were then used to develop a prediction index (PI). Finally, the PI was verified in the validation set, through ROC analysis and chi-squared test.Results: Five independent predictors were identified: tumor length ≥ 4 cm, cT4 stage, carcinoembryonic antigen ≥ 5.0 ng/mL, irradiation with three-dimensional conformal radiotherapy technique, and apolipoprotein A-I ≤ 1.20 g/L. Each of them was assigned a number of points. In the validation set, the area under the curve of PI appeared as 0.642 (95% confidence interval 0.586– 0.697). The sensitivity, specificity, positive and negative predictive values, and concordance were 72.3%, 52.3%, 63.8%, 61.9%, and 63.0%, respectively.Conclusion: Serum apolipoprotein A-I was found to correlate negatively with the RC response to NACRT. It could serve as a biomarker for guiding individualized treatment and a potential target for improving sensitivity to chemoradiation.Keywords: rectal cancer, radiotherapy, apolipoprotein A-I, tumor response, prediction model

Background The management of unresectable locally advanced colon cancer (LACC) remains controversial, as resection is not feasible. The goal of this study was to evaluate the treatment outcomes and toxicity of neoadjuvant chemoradiotherapy (NACRT) followed with surgery and adjuvant chemotherapy in patients with unresectable radically LACC. Methods We included patients who were diagnosed at our institution, 2010–2018. The neoadjuvant regimen consisted of radiotherapy and capecitabine/ 5-fluorouracil-based chemotherapy. Results One hundred patients were identified. The median follow-up time was 32 months. The R0 resection rate, adjusted nonmultivisceral resection rate and bladder preservation rate were 83.0, 43.0 and 83.3%, respectively. The pCR and clinical-downstaging rates were 18, and 81.0%%, respectively. The 3-year PFS and OS rates for all patients were 68.6 and 82.1%, respectively. Seventeen patients developed grade 3–4 myelosuppression, which was the most common adverse event observed after NACRT. Tumor perforation occurred in 3 patients during NACRT. The incidence of grade 3–4 surgery-related complications was 7.0%. Postoperative anastomotic leakage was observed in 3 patients. Conclusions NACRT followed by surgery was feasible and safe for selected patients with LACC, and can be used as a conversion treatment to achieve satisfactory downstaging, long-term survival and quality of life, with acceptable toxicities.

BackgroundThe watch-and-wait strategy offers a non-invasive therapeutic alternative for rectal cancer patients who have achieved a clinical complete response (cCR) after chemoradiotherapy. This study aimed to investigate the long-term clinical outcomes of this strategy in comparation to surgical resection.MethodsStage II/III rectal adenocarcinoma patients who received neoadjuvant chemoradiotherapy and achieved a cCR were selected from the databases of three centers. cCR was evaluated by findings from digital rectal examination, colonoscopy, and radiographic images. Patients in whom the watch-and-wait strategy was adopted were matched with patients who underwent radical resection through 1:1 propensity score matching analyses. Survival was calculated and compared in the two groups using the Kaplan–Meier method with the log rank test.ResultsA total of 117 patients in whom the watch-and-wait strategy was adopted were matched with 354 patients who underwent radical resection. After matching, there were 94 patients in each group, and no significant differences in term of age, sex, T stage, N stage or tumor location were observed between the two groups. The median follow-up time was 38.2 months. Patients in whom the watch-and-wait strategy was adopted exhibited a higher rate of local recurrences (14.9% vs. 1.1%), but most (85.7%) were salvageable. Three-year non-regrowth local recurrence-free survival was comparable between the two groups (98% vs. 98%,P = 0.506), but the watch-and-wait group presented an obvious advantage in terms of sphincter preservation, especially in patients with a tumor located within 3 cm of the anal verge (89.7% vs. 41.2%,P P = 0.874), 3-year disease-specific survival (99% vs. 96%,P = 0.643) and overall survival (99% vs. 96%,P = 0.905) were also comparable between the two groups, although a higher rate (35.7%) of distant metastases was observed in patients who exhibited local regrowth in the watch-and-wait group.ConclusionThe watch-and-wait strategy was safe, with similar survival outcomes but a superior sphincter preservation rate as compared to surgery in rectal cancer patients achieving a cCR after neoadjuvant chemoradiotherapy, and could be offered as a promising conservative alternative to invasive radical surgery.

Purpose To construct and validate a predicting genotype signature for pathologic complete response (pCR) in locally advanced rectal cancer (PGS-LARC) after neoadjuvant chemoradiation. Methods and Materials Whole exome sequencing was performed in 15 LARC tissues. Mutation sites were selected according to the whole exome sequencing data and literature. Target sequencing was performed in a training cohort (n = 202) to build the PGS-LARC model using regression analysis, and internal (n = 76) and external validation cohorts (n = 69) were used for validating the results. Predictive performance of the PGS-LARC model was compared with clinical factors and between subgroups. The PGS-LARC model comprised 15 genes. Results The area under the curve (AUC) of the PGS model in the training, internal, and external validation cohorts was 0.776 (0.697-0.849), 0.760 (0.644-0.867), and 0.812 (0.690-0.915), respectively, and demonstrated higher AUC, accuracy, sensitivity, and specificity than cT stage, cN stage, carcinoembryonic antigen level, and CA19-9 level for pCR prediction. The predictive performance of the model was superior to clinical factors in all subgroups. For patients with clinical complete response (cCR), the positive prediction value was 94.7%. Conclusions The PGS-LARC is a reliable predictive tool for pCR in patients with LARC and might be helpful to enable nonoperative management strategy in those patients who refuse surgery. It has the potential to guide treatment decisions for patients with different probability of tumor regression after neoadjuvant therapy, especially when combining cCR criteria and PGS-LARC.

117 Background: The benefit of adding Oxaliplatin to neoadjuvant chemoradiotherapy in Locally Advanced Rectal Cancer (LARC) patients remains controversial. The present study investigated whether induction chemotherapy (CapOX), 2 cycles of CapOX combined with standard radiation (Oxa-CRT) concurrently and consolidation chemotherapy (CapOX) could improve OS compared with standard treatment (nCRT) for locally advanced rectal cancer. Methods: We conducted this randomized, single center, open-label, phase III trial in China. Eligible patients were pathologically confirmed rectal adenocarcinoma, clinical T3-4 with or without regional N + and no sign of distance metastasis determined by pelvic MRI, chest and abdominal CT scan. All patients were randomly allocated to the experimental group: pelvic radiation of 50Gy/25 fractions with 4 cycles of oxaliplatin and capecitabine (1 cycle of CapOX (oxaliplatin: 130mg/m2, cape: 1000mg/m2, bid, Day 1 to Day 14) administrated before radiotherapy as induction chemotherapy, 2 cycles of CapOX (oxaliplatin: 100mg/m2, cape: 1000mg/m2, bid, Day 1 to Day 14) administrated concurrent with RT, and 1 cycle of CapOX (oxaliplatin: 130mg/m2, cape: 1000mg/m2, bid, Day 1 to Day 14) conducted as consolidation chemotherapy); or control group: radiation with capecitabine. The primary end point was OS. This trial was registered with ClinicalTrials.gov (ClinicalTrials.gov identifier: NCT02031939). Results: From January 2014 to June 2020, 556 patients enrolled in this study (n=278 in both groups), and 536 patients were evaluable (269 in experimental group and 267 patients in control group). Surgery was performed in 235 patients (84.5%) in experimental group and 242 patients (87.1%) in control group. The pCR rates were 27.8% (75 in 269) and 19.4% in control group (52 in 267) (p = 0.025). 16 and 5 patients achieved clinical complete response (cCR) in experimental and control group, respectively. Grade 3-4 toxicities were recorded in 42 (21.8%) and 6 (5.1%) patients in experimental and control group. The most common grade 3-4 toxicities were leukopenia, thrombocytopenia and neutropenia. The overall surgical complication rate was not significantly different between two groups (12.1% vs. 11.9%). Conclusions: Four cycles of CapOX combined with RT in LARC significantly increased complete tumor response in Chinese patients with acceptable toxicities. Clinical trial information: NCT02031939.

Jiawang Wei,1–3,* Rong Huang,3,* Suping Guo,1,2,* Xuhui Zhang,1,2 Shaoyan Xi,1,4 Qiaoxuan Wang,1,2 Hui Chang,1,2 Xiaohao Wang,1,2 Weiwei Xiao,1,2 Zhifan Zeng,1,2 Yuanhong Gao1,2 1State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong, People’s Republic of China; 2Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, People’s Republic of China; 3Department of Oncology, Ganzhou People’s Hospital, Ganzhou, Jiangxi, People’s Republic of China; 4Department of Pathology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, People’s Republic of China *These authors contributed equally to this work Background: The purpose of this study was to investigate the value of the postsurgical pathological T and N (ypTN) category combined with the American Joint Committee on Cancer-tumor regression grade (AJCC-TRG) in evaluating the prognosis of neoadjuvant chemoradiation therapy (NeoCRT) for locally advanced rectal cancer (LARC) to screen for a subgroup of patients with the worst prognosis. Patients and methods: In total, 265 patients with LARC were enrolled in the trial. All patients received NeoCRT. Total mesorectal excision was performed 6–8 weeks after the completion of radiotherapy. The surgical specimens were re-evaluated based on the AJCC-TRG (seventh edition) and the AJCC-tumor-node-metastasis (TNM; seventh edition) systems. We followed up these patients and calculated their overall survival (OS), disease-free survival (DFS), local recurrence-free survival (RFS), and distant metastasis (DM)-free survival (MFS) rates through the Kaplan–Meier analysis. The logrank test was further applied to evaluate the predictive value of the ypTN stage combined with AJCC-TRG for several survival indexes. Results: The median follow-up period was 65.1 months. The 5-year OS, DFS, RFS, and MFS rates were 79.4%, 68.8%, 94.4%, and 76.5%, respectively. There were significant differences in OS, DFS, and MFS rates among different ypT+AJCC-TRG and ypN+AJCC-TRG subgroups. The 5-year OS, DFS, and MFS rates for ypT3–4+TRG 1 and ypT3–4+TRG2–3 subgroups were 73.9% vs 65.3%, 61.2% vs 52.9%, and 65.0% vs 61.5%, respectively. The 5-year OS, DFS, and MFS rates for ypN1–2+TRG 0–1 and ypN1–2+TRG2–3 subgroups were 64.8% vs 54.1%, 44.9% vs 41.7%, and 61.4% vs 46.3%, respectively. Conclusion: The ypTNM category combined with the AJCC-TRG can more accurately evaluate the prognosis of patients with LARC and identify the subgroup of patients with the worst prognosis and high risk of developing DM, thereby demonstrating clinical significance in guiding individualized postoperative adjuvant therapy and follow-up for LARC. Keywords: ypTNM, NeoCRT, rectal cancer, locally advanced rectal cancer, LARC, AJCC

To explore clinical characteristics which could be applied to predict pathologic complete response (pCR) for patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy (neo-CRT) and total mesorectal excision (TME). 297 patients with locally advanced rectal cancer (cT3-4 or cN+) who were treated with neo-CRT followed by TME were retrospectively reviewed. Clinical characteristics including age, gender, tumor distance from anus, serum CEA, hemoglobin levels before treatment and clinical TN stage were used to investigate the association with pCR after neo-CRT. Seventy-nine (26.6%) patients achieved pCR after neo-CRT. pCR were achieved in 42 (34.4%) patients in cT1-3 stage and 37 (21.1%) in cT4 stage. pCR rate was 36.4% and 16.4% for patients with pre-treatment serum CEA ≤5.33ng/ml and >5.33ng/ml, respectively. Uni- and multi-variate analyses revealed that pre-treatment serum CEA level ≤5.33ng/ml and clinical T stage, (i.e., cT1-3 versus cT4) were highly correlated with pCR (p < 0.05). Clinical T stage and pre-treatment serum CEA level were strongly associated with pCR for patients with locally advanced rectal cancer treated with neo-CRT followed by TME which could be applied as clinical predictors for pCR.

Background: Appropriate cycle number of perioperative chemotherapy for patients with locoregionally advanced rectal cancer (LARC) remains unknown. This study aimed to evaluate how cycle number of perioperative chemotherapy influenced the prognosis of LARC patients. Methodology / Principal Findings: In this study, a total of 388 consecutive patients were enrolled and retrospectively reviewed if they were diagnosed with untreated stage cII-III LARC and treated with neoadjuvant chemoradiotherapy plus radical surgery followed by adjuvant chemotherapy or not. After grouping by the postoperative pathologic stage (yp0-I vs. ypII-III), propensity score matching was performed in each group to balance baseline characteristics between the patients treated with chemotherapy cycle ≤ 7 and those treated with chemotherapy cycle ≥ 8. The chemotherapy cycle was analyzed for its association with the survivals of the matched patients in the 2 groups, respectively. And the incidence of treatment-related complications was also compared. Through analysis, chemotherapy cycle ≥ 8 appeared to predict better overall, disease-free and distant-metastasis-free survivals in the whole cohort of matched patients (P values were 0.003, 0.002 and 0.004, respectively) and the ypII-III group (P values were 0.006, 0.005 and 0.014, respectively). But in the yp0-I group, chemotherapy of 8 cycles or more brought no improvement of survivals but only more acute toxicities (83.5% vs. 57.0%, P < 0.001). Conclusions / Significance: Chemotherapy cycle ≥ 8 was proven associated with improved prognosis of LARC patients, especially those with ypII-III disease. But prolonged chemotherapy should be performed with caution in patients with yp0-I stage.

Purpose Oligometastatic disease can potentially be cured when an optimal approach is performed. Early recurrence after liver resection is an intractable problem, and the clinical implications remain unknown in colorectal liver oligometastases (CLOM) patients. This study aimed to investigate the clinical characteristics, risk factors, and prognosis related to early recurrence in these patients. Methods A total of 307 consecutive patients with CLOM undergoing curative liver resection were retrospectively reviewed between September 1999 and June 2016. Early recurrence was defined as any recurrence or death from CLOM that occurred within 6 months of liver resection. Results With a median follow-up time of 31.7 months, the 3-year overall survival (OS) and recurrence-free survival rates were 68.7 and 42.5%, respectively. Forty-nine (16.0%) patients developed early recurrence and showed a poorer 3-year OS than those with non-early recurrence (22.3 vs. 75.8%, P 3 cm (OR 2.560; 95% CI 1.290–5.078; P = 0.007) were shown to be risk factors for early recurrence. The salvage liver resection rate for patients with early recurrence was significantly lower than that for patients with later recurrence (4.1 vs. 19.7%, P = 0.010). Conclusions Early recurrence should be investigated in routine clinical practice, even in patients with CLOM after curative liver resection. Detailed preoperative comprehensive measurements might help stratify high-risk patients, and a non-surgical treatment for early recurrence might represent an effective alternative.

TPS3615 Background: Standard treatment of rectal cancer is neoadjuvant capecitabine chemotherapy with radiotherapy, followed by total mesorectal excision (TME). Total neoadjuvant treatment (TNT), a new concept, suggests organ preservation as an alternative to rectal excision in good responders after neoadjuvant chemoradiotherapy to decrease surgical morbidity and increase quality of life. RAPIDO and PRODIGE-23 trials showed that TNT strategy could improve the pathological complete response (pCR) rateand reduce the risk of distant metastasis. The objective of this trial is to increase the proportion of sphincter preservation rate for distal rectal cancer patients by optimizing tumor response, by using TNT regimen as compared to conventional chemoradiotherapy. TESS (clinicalTrials.gov, NCT03840239), a prospective, open label, multicenter, randomized phase 2 study, is underway. Methods: Main inclusion criteria include: cT3-4aNany or cTanyN+ rectal adenocarcinoma aged 18-70y; ECOG performance 0-1; distance≤5cm from anal verge. 168 patients will be randomized 1:1. Patients in the TNT group will receive 2 cycles of neoadjuvant chemotherapy Capeox (capecitabine + oxaliplation) before, during and after radiotherapy 50Gy/25 fractions, before TME (or other treatment decisions, such as watch and wait) and adjuvant chemotherapy capecitabine 2 cycles. Patients in the standard treatment group will receive neoadjuvant radiotherapy 50Gy/25 fractions combined with capecitabine 5 weeks before TME (or other treatment decisions, such as watch and wait), and adjuvant chemotherapy Capeox 6 cycles. Primary endpoint is the rate of sphincter preservation rate (absence of stoma). Secondary endpoints include: Ratio of sphincter preservation strategy; pathological complete response rate and tumor regression grade distribution; acute toxicity; surgical complications; long-term anal function; late toxicity; ECOG standard score; disease-free survival; overall survival. First site opened in January 24, 2019. Clinical trial information: NCT03840239.

e15500 Background: Efficacy and safety of PD-1 inhibitors have been approved for the treatment of metastatic anal squamous cancer patients, but the efficacy of neoadjuvant treatment with PD-1 in anal squamous cancer patients has not yet been defined. We report results for the cohort of patients with locally advanced anal canal squamous carcinoma treated with neoadjuvant PD-1 inhibitor toripalimab and chemotherapy followed by concurrent immunoradiotherapy. Methods: Five locally advanced anal canal squamous carcinoma patients received 4 cycles of neoadjuvant PD-1 inhibitor toripalimab and Docetaxol and Cisplatin chemotherapy followed by concurrent immunoradiotherapy. Whole exome sequencing (WES) and mIHC were performed with the pretreatment tumor tissue for biomarker analysis. Results: Complete clinical response (cCR) was achieved in 4 patients after neoadjuvant treatment before radiotherapy while the other patient achieved near cCR. cCR was achieved in all the 5 patients 3 months after definitive immunoradiotherapy. Grade 3 toxicity was noted in 1 patient. Molecular testing revealed that PD-L1 expression (≥1%) in tumor and CD4/CD163 expression in tumor and paracancerous tissue were positively correlated with tumor shrinkage in the neoadjuvant treatment phase while TMB didn’t appear to significantly impact the response. Conclusions: PD-1 inhibitor combined with chemoradiotherapy has quite promising effect in locally advanced anal canal squamous carcinoma patients, with very mild toxicity. Pretreatment PD-L1 expression is positively correlated with tumor response to PD-1 inhibitor toripalimab and chemotherapy. It is worthy of further investigation in prospective clinical trial.

// Lin Xiao 1,2,3,* , Xin Yu 1,2,* , Rong Zhang 2,4,* , Hui Chang 1,2 , Shaoyan Xi 2,5 , Weiwei Xiao 1,2 , Zhifan Zeng 1,2 , Huizhong Zhang 2,5 , Ruihua Xu 2,6 , Yuanhong Gao 1,2 1 Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China 2 State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, China 3 Department of Oncology, Section II, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-sen University, Jiangmen, China 4 Department of Endoscopy and Laser, Sun Yat-sen University Cancer Center, Guangzhou, China 5 Department of Pathology, Sun Yat-sen University Cancer Center, Guangzhou, China 6 Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China * These authors contributed equally to the paper Correspondence to: Yuanhong Gao , email: // Ruihua Xu, email: // Keywords : interleukin-13, single-nucleotide polymorphism, locally advanced rectal cancer, neoadjuvant chemoradiotherapy, prognosis Received : December 04, 2015 Accepted : April 16, 2016 Published : May 04, 2016 Abstract We sought to determine whether a polymorphism in the Interleukin 13 gene ( IL13 ), 1112 C/T (rs1800925) predicts responsiveness to neoadjuvant chemoradiotherapy (neoCRT) and prognosis in Chinese Han patients with locally advanced rectal cancer (LARC). Pre-treatment biopsies of primary rectal lesion and surgical specimens were collected from 58 patients with LARC, who were treated with neoCRT and surgery. Tumor DNA was extracted from these biopsies and sequenced to analyze the rs1800925 polymorphism. The tumor response to neoCRT was categorized using a tumor regression grade (TRG, 0-2 were poor responders; 3-4 were good responders). Analyses of progression free survival (PFS) and overall survival (OS) were carried out using the Kaplan-Meier method. Of the forty-six patients for whom tumor DNA was successfully sequenced, 23 were good responders to neoCRT (11 patients with a pathological complete response, i.e. pCR) and the other 23 were poor responders. Good and poor responders were equally likely to have a C/C genotype at rs1800925 (73.9%) as a T/T or C/T genotype (26.1%). There were no differences between the C/C and T/T+C/T genotypes with respect to the ypT0-2 ratio (38.2% vs. 41.7%, P = 1.0) , ypN0 nodal status (67.6% vs. 50.0%, P = 0.314), 6-year PFS (67.6% vs. 50%, P =0.274), or 6-year OS (76.5% vs. 66.7%, P =0.441). Thus, the IL13-1112 C/T (rs1800925) polymorphism does not predict responsiveness to neoCRT or prognosis of Chinese Han patients with LARC.

Background: The watch-and-wait strategy offers a non-invasive therapeutic alternative for rectal cancer patients who achieved clinical complete response (cCR) after chemoradiotherapy. However, concerns about the safety of this treatment strategy remain. Methods: Stage II/III rectal adenocarcinoma patients who received neoadjuvant chemoradiotherapy and achieved cCR from Sept 1, 2010 to Jan 30, 2018 at three centers in China were included. cCR patients who adopted the watch-and-wait strategy were compared to cCR patients who had standard surgical resection. The primary end point was disease-specific survival (DSS). All end points were calculated and compared with log-rank test in a non-matched cohort and a 1:3 ratio propensity-score paired match cohort. Findings: 471 cCR patients were included, of which 354 were in the watch-and-wait group and 354 in the surgical group. Compared to the surgical group, patients managed by watch-and-wait had earlier T-stage but more distally located tumors, of whom 22 patients had local regrowth, and 17 of them were salvaged by surgery. Ultimately, sphincter preservation was achieved in 108 (92*3%) patients in the watch-and-wait group, and in 283 (79*9%) patients in the surgical group (p=0*002). The 3-year distant metastasis-free survival (DMFS) were 89% versus 87%, 3-year DSS were 99% versus 96% and the 3-year overall survival were 99% versus 96% for the watch-and-wait and the surgical group, respectively. After matching, difference in T-stage was not significant, and survival analyses also showed no significant difference between the two groups. We did observed a lower 3-year DMFS in patients with local regrowth compared to those with sustain cCR (75% versus 93%, p=0*044), however, this was comparable to the 3-year DMFS of the non-pathological complete responders of the surgical group (p =0*730). Interpretation: Rectal cancer patients achieving cCR and treated with the watch-and-wait strategy had similar survival outcomes but superior sphincter preservation rate as compared to those who underwent radical surgery and a trend of higher distant metastasis rate observed in local regrowth patients should not be considered as the main concern for treatment decision. Funding Statement: The National Natural Science Foundation of China (81672987). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: All the procedures were approved by the ethical committee at each center, which also waived the necessity of patients’ informed consent due to the retrospective nature of this study.

Background The preliminary results of our phase II randomized trial reported comparable functional sphincter preservation rates and short-term survival outcomes between patients undergoing total mesorectal excision (TME) with or without preoperative concurrent chemoradiotherapy (CCRT). We now report the long-term results after a median follow-up of 71 months. Methods Between March 23, 2008 and August 2, 2012, 192 patients with T3-T4 or node-positive, resectable, mid/low rectal adenocarcinoma were randomly assigned to receive TME with or without preoperative CCRT. The following endpoints were assessed: cumulative rates of local recurrence and distant metastasis, disease-free survival (DFS), and overall survival (OS). Results The data of 184 eligible patients were analyzed: 94 patients in the TME group and 90 patients in the CCRT + TME group. In the whole cohort, the 5-year DFS and OS rates were 84.8% and 85.1%, respectively. The 5-year DFS rates were 85.2% in the CCRT + TME group and 84.3% in the TME group (P = 0.969), and the 5-year OS rates were 83.5% in the CCRT + TME group and 86.5% in the TME group (P = 0.719). The 5-year cumulative rates of local recurrence were 6.3% and 5.0% (P = 0.681), and the 5-year cumulative rates of distant metastasis were 15.0% and 15.7% (P = 0.881) in the CCRT + TME and TME groups, respectively. No significant improvements in 5-year DFS and OS were observed with CCRT by subgroup analyses. Conclusions Both treatment strategies yielded similar long-term outcomes. A selective policy towards preoperative CCRT is thus recommended for rectal cancer patients if high-quality TME surgery and enhanced chemotherapy can be performed. Trial registration ChiCTR-TRC-08000122. Registered 16 July 2008

OBJECTIVES: Pathological complete response has shown a better prognosis for patients with locally advanced rectal cancer after preoperative chemoradiotherapy. However, correlations between post-chemoradiotherapy clinical factors and pathologic complete response are not well confirmed. The aim of the current study was to identify post-chemoradiotherapy clinical factors that could serve as indicators of pathologic complete response in locally advanced rectal cancer. METHODS: This study retrospectively analyzed 544 consecutive patients with locally advanced rectal cancer treated at Sun Yat-sen University Cancer Center from December 2003 to June 2014. All patients received preoperative chemoradiotherapy followed by surgery. Univariate and multivariate regression analyses were performed to identify post-chemoradiotherapy clinical factors that are significant indicators of pathologic complete response. RESULTS: In this study, 126 of 544 patients (23.2%) achieved pathological complete response. In multivariate analyses, increased pathological complete response rate was significantly associated with the following factors: post-chemoradiotherapy clinical T stage 0-2 (odds ratio=2.098, 95% confidence interval=1.023-4.304, p=0.043), post-chemoradiotherapy clinical N stage 0 (odds ratio=2.011, 95% confidence interval=1.264-3.201, p=0.003), interval from completion of preoperative chemoradiotherapy to surgery of >;7 weeks (odds ratio=1.795, 95% confidence interval=1.151-2.801, p=0.010) and post-chemoradiotherapy carcinoembryonic antigen ≤2 ng/ml (odds ratio=1.579, 95% confidence interval=1.026-2.432, p=0.038). CONCLUSIONS: Post-chemoradiotherapy clinical T stage 0-2, post-chemoradiotherapy clinical N stage 0, interval from completion of chemoradiotherapy to surgery of >;7 weeks and post-chemoradiotherapy carcinoembryonic antigen ≤2 ng/ml were independent clinical indicators for pathological complete response. These findings demonstrate that post-chemoradiotherapy clinical factors could be valuable for post-operative assessment of pathological complete response.

To compare the short-term efficacy and treatment-related adverse reaction between preoperative three dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT) concurrently combined with chemotherapy in the treatment of locally advanced rectal carcinoma (LARC).Clinical data of 334 patients with LARC undergoing preoperative 3D-CRT(172 cases) or VMAT(162 cases) with concurrent Xelox chemotherapy (main protocol: capecitabine plus oxaliplatin) and surgery in Sun Yat-sen University Cancer Center from May 2007 to April 2013 were retrospectively analyzed. The total radiation dose of VMAT group was: 50 Gy/2.0 Gy per fraction ×23 fractions for planning target volume 1(PTV1) and 46 Gy/1.84 Gy per fraction ×25 fractions for PTV2; the total radiation dose of 3D-CRT group was: 46 Gy/2.0 Gy per fraction ×23 fractions for PTV. The treatment-related adverse reaction of both groups during chemoradiotherapy was measured according to the criteria of Common Terminology Criteria for Adverse Events v3.0 (CTCAE 3.0). Rate of adverse reaction and short-term efficacy between 3D-CRT and VMAT group were compared, in terms of radiotherapy break, hematological and non-hematological toxicity, average duration of surgery and perioperative hospitalization, intraoperative blood loss, surgical procedures, R0 excision, sphincter preservation, postoperative complications, pathological complete response (pCR), and postoperative pathological staging.There were no significant differences in baseline clinical parameters between 3D-CRT and VMAT group (all P0.05), except for the distance from lower tumor margin to anal verge (P=0.009). The median radiation dose for all the patients was 46 (45 to 70) Gy. There was no significant difference in the rate of radiotherapy cessation between 3D-CRT and VMAT group [1.7%(3/172) vs. 1.2%(2/162), P=1.000]. During concurrent chemotherapy, incidences of grade 2 to 3 hematological toxicities, grade 2 diarrhea, and grade 3 non-hematological toxicities were not significantly different(all P0.05), while in grade 2 non-hematological toxicities, ratio of radiodermatitis and hand-foot syndrome was higher in VMAT group as compared to 3D-CRT group [25.9%(42/162) vs. 10.5%(18/172), P=0.000; 3.7%(6/162) vs. 0, P=0.012]. There was no grade 4 adverse event in both groups. Surgical procedure, average duration of surgery, R0 excision, anus preservation, postoperative complications, pCR, and postoperative pathological staging were not significantly different(all P0.05). As compared to 3D-CRT group, VMAT group had less intraoperative blood loss [(114.6±100) ml vs. (169±143.9) ml, P0.001] and shorter perioperative hospitalization [16(8 to 84) d vs. 20(10 to 47) d, P0.001]. There was no death case in two groups within 30 days after operation.Compared with 3D-CRT technique, preoperative VMAT technique can not significantly reduce the incidence of treatment-related adverse reaction and improve the short-term efficacy in the treatment of LARC.

Our previous study reported the favorable short-term outcome and good tolerance of integrating oxaliplatin into capecitabine-based (XELOX regimen) preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC). The present study reported the long-term oncological outcome of this phase II study. A total of 47 patients with rectal adenocarcinoma (stage II or III) were enrolled and received radiotherapy (46 Gy in 23 fractions) in combination with capecitabine (1,000 mg/m2, twice daily, on days 1-14 and 22-35) and oxaliplatin (130 mg/m2 on days 1 and 22). Overall survival (OS) rate, disease-free survival (DFS) rate and cumulative incidence of recurrences and long-term complications were calculated or observed. As a result, 41 patients underwent surgery after preoperative CRT, and the cumulative OS rates at 1, 3 and 5 years for these patients were 100.0, 84.5 and 81.8%, respectively. For the 38 patients who received R0 resection, the cumulative OS rates at 1, 3 and 5 years were 100.0, 89.0 and 86.2%, respectively, while the cumulative DFS rates at 1, 3 and 5 years were 94.6, 75.3 and 69.7%, respectively. After follow-up at 84 months, the cumulative incidence rates of local and distant recurrences at 5 years were 6.6 and 28.2%, respectively. Oxaliplatin-associated long-term complications were seldom observed. Overall, the addition of oxaliplatin to capecitabine-based preoperative radiotherapy achieved favorable OS and DFS without increased long-term complications in patients with LARC. Therefore, this preoperative CRT strategy is a feasible option for such patients.

CURD is one type of clustering algorithm based on reference point and density. This algorithm is similar to DBSCAN in processing arbitrary shape clustering ability and has linear time complexity of K-MEANS algorithm. CURD algorithm needs to set Radius and t, so the whole process of clustering needs manual intervention which has the similarity with most of clustering algorithm. This paper proposes SA-CURD clustering algorithm based on CURD which can automatically set Radius and t by analyzing dataset statistics, in order avoid manual intervention in the process of clustering and achieve complete automation. Experiments show that SA-CURD can rationally choose Radius and t and get highly precise clustering results. Keywords-Data Mining; Clustering; SA-CURD; CURD

e14040Background: Although neoadjuvant chemoradiotherapy has significantly reduced the risk of local recurrence in locally advanced rectal cancer, systemic failure remains a predominant issue proba...

727 Background: To analyze the outcomes of neoadjuvant chemoradiotherapy (neoCRT) in the management of unresectable locally advanced adherent colon cancer (LAACC). Methods: 40 unresectable LAACC patients were identified from Sun Yat-Sen university cancer-center Database from October 2010 to December 2014. Unresectability was determined by multidisciplinary consultation (MDT) according to image examination or confirmed by exploratory laparotomy. NeoCRT followed by surgery and postoperative chemotherapy were given to these patients. There were 27 males and 13 females. Median age was 56 years old. The location of primary tumors were as sigmoid 31, descending colon 3, ascending colon 5, and cecum1, respectively. All the patients were treated with 45-50Gy/25F using 3D-CRT or IMRT, and concomitantly with capecitabine-based chemotherapy every 3 weeks. Surgery was scheduled 6-8 weeks after completion of radiotherapy. Results: A total of 40 patients completed neoCRT and 33 patients (82.5%) received radical resection for the locally diseases, with R0 and R2 resection in 30 and 3 patients, respectively. Seven patients were assessed as unresectable after neoCRT and 3 of them received only colostomy while the other 4 continued chemotherapy. Pathological complete response was documented in 8 patients (20.0%). Multivisceral resection was necessary in 15 patients (36.6%). Among the 33 patients underwent curative surgery, bladder invasion was noticed at diagnosis in 17 patient and bladder function was preserved in all these patients, with full bladder preserving approach in 6 and partial cystectomy in 11 patients. Grade-2 post-operative complications were observed in 4 patients (10.0%) with no 30-day mortality. Median follow-up was 26 months. For all the patients, the 3-year overall survival, local progression-free survival and progression-free survival were 70.8%, 88.2%, 74.5%, respectively. Conclusions: NeoCRT is an effective strategy for the treatment of unresectable LAACC, with high R0 resection rate, satisfactory organ preservation, good local control and acceptable treatment toxicity. NeoCRT in LAACC is worthy of further clinical research.