Volume De-escalation in Neoadjuvant Radiochemotherapy of Rectal Cancer

The study outlines a clinical prospective protocol consisting of preoperative chemoradiation in locally advanced rectal cancer, without elective pelvic nodal irradiation. The proposal to exclude lateral spaces from the target volume is based on the assumption that the radiological evidence of recurrence in the lateral lymph nodes is shown to be below 5%. In the study all patients underwent an accurate pre-treatment work-up including total body CT, pelvic MRI and 18-fluorodeoxyglucose PET/CT, in order to include patients without evidence of disease in lateral lymph nodes. The primary endpoint of the study was the reduction of gastrointestinal toxicity; secondary endpoints were the pathological complete response (pCR), the local control (LC) rate, the overall survival (OS) and the disease-free survival (DFS).

Patients affected by histologically proven rectal cancer were considered for enrollment in a prospective protocol that included preoperative CRT and surgical treatment. All patients underwent pre-treatment work-up (clinical examination, pancolonoscopy with biopsy, total body CT scan, pelvic MRI, and whole body 18-fluorodeoxyglucose PET/CT scan). Eligible patients had primary resectable cT2-low lying-T3, N0-N1 adenocarcinoma of the rectum, without evidence of disease in lateral lymph nodes. Additional eligibility criteria included performance status as well as liver, kidney, and bone marrow function that allowed for long-course CRT, older than 18 years, and no distant metastases.

Primary resectable cT2-low lying-T3, N0-N1 adenocarcinoma of the rectum, without evidence of disease in lateral lymph nodes.

Patient treated with reduced radiation volumes with the exclusion of elective pelvic nodal irradiation

The LC will be calculated by the Kaplan-Meier method. Evaluation of differences will be performed with the log-rank test. Survival will be censored at the time of the last follow-up or death. A two-sided P value of 0.05 will be considered significant.

The OS will be calculated by the Kaplan-Meier method. Evaluation of differences will be performed with the log-rank test. Survival will be censored at the time of the last follow-up or death. A two-sided P value of 0.05 will be considered significant.

The DFS will be calculated by the Kaplan-Meier method. Evaluation of differences will be performed with the log-rank test. Survival will be censored at the time of the last follow-up or death. A two-sided P value of 0.05 will be considered significant.

Inclusion Criteria: Primary resectable cT2-low lying-T3, N0-N1 adenocarcinoma of the rectum, without evidence of disease in lateral lymph nodes No distant metastases Exclusion Criteria: Evidence of disease in lateral lymph nodes Distant metastases