Background: Neoadjuvant chemoradiation therapy (CRT) increases pathological complete response (pCR) rates compared to radiotherapy alone in patients with stage II-III rectal cancer. Limited evidence addresses whether radiotherapy dose escalation further improves pCR rates. Our purpose is to measure the effects of radiotherapy dose and other factors on post-therapy pathologic tumor (ypT) and nodal stage in rectal cancer patients treated with neoadjuvant CRT followed by mesorectal excision. Material and methods: A non-randomized comparative effectiveness analysis was performed of rectal cancer patients treated in 2000–2013 from the National Oncology Data Alliance™ (NODA), a pooled database of cancer registries from >150 US hospitals. The NODA contains the same data submitted to state cancer registries and SEER combined with validated radiotherapy and chemotherapy records. Eligible patients were treated with neoadjuvant CRT followed by proctectomy and had complete data on treatment start dates, radiotherapy dose, clinical tumor (cT) and ypT stage, and number of positive nodes at surgery (n = 3298 patients). Multivariable logistic regression was used to assess the predictive value of independent variables on achieving a pCR. Results: On multivariable regression, radiotherapy dose, cT stage, and time interval between CRT and surgery were significant predictors of achieving a pCR. After adjusting for the effect of other variates, patients treated with higher radiotherapy doses were also more likely to have negative nodes at surgery and be downstaged from cT3-T4 and/or node positive disease to ypT0-T2N0 after neoadjuvant CRT. Conclusion: Our study suggests that increasing dose significantly improved pCR rates and downstaging in rectal cancer patients treated with neoadjuvant CRT followed by surgery.

Objectives To categorize sites of recurrence of retroperitoneal sarcomas (RPS) and correlate to clinical treatment volumes of postoperative radiation therapy (PORT) with or without intraoperative radiation therapy (IORT). Methods A retrospective review of patients with RPS who received PORT between 1990 and 2008 was done. Tumor recurrences were subdivided as local tumor bed, regional adjacent retroperitoneal fascial tissues, peritoneal diffuse seeding, and distant metastases. Results PORT was given to 33 patients, 20 of whom also received IORT. Local recurrences appeared in 4 (12%) cases. Regional recurrences appeared in 8 (26%) cases, including 5 with in-field recurrence and 3 with edge-of-field recurrence. Edge-of-field recurrences developed in 3 of 11 (27%) patients whose clinical presentation was local recurrence compared with none of 20 patients whose clinical presentation was a primary tumor (P=0.037). Late grades 3 to 4 gastrointestinal toxicities appeared in 1 of 10 (10%) patients who received intensity-modulated radiation therapy (IMRT) with a minimum 15-month follow-up compared with 4 of 15 (27%) patients who received standard RT. Conclusions Use of techniques such as IORT and IMRT can deliver a dose of approximately 60 Gy to the tumor bed and 44 to 51 Gy to the surrounding retroperitoneal fascial planes. Acute and late gastrointestinal toxicities were less frequent with IMRT compared with conventional PORT with IORT. These results may provide the basis for comparison of various adjuvant therapy strategies for RPS. As radiation therapy is a loco-regional treatment, results should be reported by tumor recurrence subtypes of local, regional, peritoneal, and distant.