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Purpose: The role of biliary stents in image‐guided localization for pancreatic cancer has been inconclusive. To date, stent accuracy has been largely evaluated against implanted fiducials on cone beam computed tomography. We aim to use magnetic resonance (MR) soft tissue as a direct reference to examine the geometric and dosimetric impacts of stent‐based localization on the newly available MR linear accelerator. Methods: Thirty pancreatic cancer patients (132 fractions) treated on our MR linear accelerator were identified to have a biliary stent. In our standard adaptive workflow, patients were set up to the target using soft tissue for image registration and structures were re‐contoured on daily MR images. The original plan was then projected on treatment anatomy and dose predicted, followed by plan re‐optimization and treatment delivery. These online predicted plans were soft tissue‐based and served as reference plans. Retrospective image registration to the stent was performed offline to simulate stent‐based localization and the magnitude of shifts was taken as the geometric accuracy of stent localization. New predicted plans were generated based on stent‐alignment for dosimetric comparison. Results: Shifts were within 3 mm for 90% of the cases (mean = 1.5 mm); however, larger shifts up to 7.2 mm were observed. Average PTV coverage dropped by 1.1% with a maximum drop of 26.8%. The mean increase in V35Gy was 0.15, 0.05, 0.02, and 0.02 cc for duodenum, stomach, small bowel and large bowel, respectively. Stent alignment was significantly worse for all metrics except for small bowel (p = 0.07). Conclusions: Overall discrepancy between stent‐ and soft tissue‐alignment was modest; however, large discrepancies were observed for select cases. While PTV coverage loss may be compensated for by using a larger margin, the increase in dose to gastrointestinal organs at risk may limit the role of biliary stents in image‐guided localization. [ABSTRACT FROM AUTHOR]

Background: A study was undertaken to determine the survival benefit of postoperative chemoradiation therapy for elderly patients with resected gastric adenocarcinoma.Methods: The authors identified 1023 individuals aged 65 years and older (median = 76) who underwent gastrectomy for nonmetastatic stage IB-IV gastric adenocarcinoma diagnosed between 2000 and 2002 in the linked Surveillance, Epidemiology, and End Results-Medicare database. They examined factors associated with receiving postoperative chemoradiation and analyzed the survival benefit associated with receiving postoperative chemoradiation.Results: Thirty percent of patients received adjuvant chemoradiation. On multivariate analysis, younger age (P < .0001), lymph node involvement (P < .0001), and more recent diagnosis (P = .0284) were associated with receiving chemoradiation. There was a trend toward increased use among patients with less comorbidity (P = .0515). The median follow-up was 25.5 months, and 62% died. On multivariate survival analysis, older patients (P < .0001) and those with lymph node involvement (P < .0001), T3 or T4 disease (P = .0472), higher grade disease (P = .0355), and more comorbidity (P = .0411) were more likely to die. After adjustment for other factors, receipt of adjuvant chemoradiation therapy did not significantly increase survival (hazard ratio, 0.90; 95% confidence interval, 0.72-1.12; P = .3453) and did not increase survival in a multivariate analysis that included propensity scores (P = .2090).Conclusions: The authors did not detect a survival benefit, suggesting that some elderly patients with resected gastric adenocarcinoma may not gain a survival benefit from the administration of adjuvant chemoradiation. The analysis had limitations, and the results are hypothesis generating. Future gastric cancer trials should enroll more elderly patients and stratify patients by age to better understand the impact of treatment regimens on older patients. [ABSTRACT FROM AUTHOR]

BACKGROUND: The purpose of this study was to assess the efficacy and safety of 5-fluorouracil (5FU) and gemcitabine administered concurrently with radiation in patients with locally advanced, nonmetastatic pancreatic cancer. METHODS: Eligible patients had histologically confirmed pancreatic adenocarcinoma deemed locally unresectable without evidence of metastatic disease. In addition, all patients underwent laparoscopy or laparotomy before study entry to rule out peritoneal carcinomatosis. Patients received radiation therapy (50.4 Gy) with concurrent infusional 5FU (200 mg/m² 5 days/week) and weekly gemcitabine (200 mg/m²). After a 3-week break, patients received weekly gemcitabine at 1000 mg/m² for 3 of 4 weeks, for 4 cycles. The primary endpoint of the trial was the proportion of patients surviving 9 months from study entry. Secondary endpoints included objective tumor response, CA19-9 response, overall survival (OS) time to progression (TTP), and toxicity. RESULTS: Between November 2001 and October 2004, 81 patients were enrolled, 78 of whom were eligible for analysis. With a median follow-up of 55.2 months, the median OS was 12.2 months (95% confidence interval [CI], 10.9-14.9) and the median TTP was 10 months (95% CI, 6.4-12.0). An objective tumor response was seen in 19 patients (25%), and among 56 patients with an elevated CA19- 9 at baseline, 29 (52%) had a sustained CA19-9 response. Overall, 41% of patients had grade 3 or greater treatment-related gastrointestinal adverse events. CONCLUSIONS: The combination of 5FU, gemcitabine, and radiation is well tolerated. Survival is comparable with the best results of other recent studies of 5FU and radiation or gemcitabine and radiation. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the importance of patient-reported outcomes (PROs) to identify the symptoms of acute gastrointestinal (GI) toxicity while concurrent 5-fluorouracil-based chemoradiation therapy is conducted to treat rectal cancer. It mentions the use of the 7-item Bowel Problems Scale questionnaire to study the data gathered from PROs. Results show that PROs provide additional information on the symptoms experienced by patients which might have been overlooked.

In previous studies, an electronic portal imaging device (EPID) in cine mode was used for validating respiratory gating and stereotactic body radiation therapy (SBRT) by tracking implanted fiducials. The manual marker tracking methods that were used were time and labor intensive, limiting the utility of the validation. The authors have developed an automatic algorithm to quickly and accurately extract the markers in EPID images and reconstruct their 3D positions. Studies have been performed with gold fiducials placed in solid water and dynamic thorax phantoms. In addition, the authors have examined the cases of five patients being treated under an SBRT protocol for hepatic metastases. For each case, a sequence of images was created by collecting the exit radiation using the EPID. The markers were detected and recognized using an image processing algorithm based on the Laplacian of Gaussian function. To reduce false marker detection, a marker registration technique was applied using image intensity as well as the geometric spatial transformations between the reference marker positions produced from the projection of 3D CT images and the estimated marker positions. An average marker position in 3D was reconstructed by backprojecting, towards the source, the position of each marker on the 2D image plane. From the static phantom study, spatial accuracies of <1 mm were achieved in both 2D and 3D marker locations. From the dynamic phantom study, using only the Laplacian of the Gaussian algorithm, the marker detection success rate was 88.8%. However, adding a marker registration technique which utilizes prior CT information, the detection success rate was increased to 100%. From the SBRT patient study, intrafractional tumor motion (3.1–11.3 mm) in the SI direction was measured using the 2D images. The interfractional patient setup errors (0.1–12.7 mm) in the SI, AP, and LR directions were obtained from the average marker locations reconstructed in 3D and compared to the reference planning CT image. The authors have developed an automatic algorithm to extract marker locations from MV images and have evaluated its performance. The measured intrafractional tumor motion and the interfractional daily patient setup error can be used for off-line retrospective verification of SBRT. [ABSTRACT FROM AUTHOR]

The article reports on the study that examines the experience of patients who were treated with adjuvant 5-fluorouracil and radiation therapy (RT) for resected pancreatic adenocarcinoma. It found that 33% of patients have positive resection margins, while 81% of tumors were classified as T3 and 66% of patients have involved lymph nodes. It was concluded that lymph nodes status and treatment with adjuvant chemotherapy were significant predictors of overall survival and disease-free survival.

Stereotactic body radiation therapy is predicated on a high degree of targeting accuracy. However, inaccurate patient setup as well as intra-fractional motion can hinder the delivery of high doses preferentially to the target. To ensure that the coverage delivered to the patient is as planned, an image-guided verification system has been created to estimate the delivered dose retrospectively. This will not only aid the assessment of treatment techniques, but will also allow for more accurate dose response analysis. Patients with limited hepatic metastases from solid tumors were treated with SBRT. Implanted gold markers were used as target surrogates and a body frame and compression plate provided stereotactic localization and target immobilization, respectively. During treatment, an electronic portal imaging device (EPID), operating in cine mode, collected the exit dose. The sequences of images for each field were processed off-line using in-house software for registration and seed localization. The beam’s-eye-view seed positions in the treatment images were compared to those in the DRR’s to determine the target shifts in the imaging plane. These target shifts were then imported into the treatment planning software. Each original field was multiplied by the number of images taken during treatment. The calculated shift from each image was then applied to each of the new subfields. Summing all of these subfields together gives the dose distribution that was actually delivered to the patient. The dose-volume histograms for the planned and delivered distributions for four patients’ complete treatments are shown. For two of the patients, underdosing due to a setup error or intra-fractional drift was not wholly resolved by subsequent fractions. For one of these patients two alternative corrective strategies have been applied, retrospectively, and the prescribed target coverage recovered for both. The delivered dose can be estimated using the information contained in cine EPID images acquired during irradiation. Calculating the dose actually delivered to the target will allow us to assess treatment procedures as well as more accurately report clinical results. [ABSTRACT FROM AUTHOR]

The article discusses the improvements on the adjuvant treatment of colorectal cancer for the past 10 years. Advances in surgery, radiation and chemotherapy resulted to progress in localized colorectal cancer treatment while the use of total mesorectal excision and preoperative chemoradiotherapy lead to improve outcomes in treatment of rectal cancer. Oxaliplatin has been incorporated into colon cancer adjuvant therapy programs while new targeted agents are already in preclinical trials.