3537 - Short-Course Radiotherapy, Chemotherapy and Surgery in Rectal Cancer Patients under 50: Recurrence and Survival Outcomes

Purpose/Objective(s): This study aims to evaluate the recurrence patterns and survival outcomes of rectal cancer patients under the age of 50 who have undergone short-course radiotherapy (SCRT), and chemotherapy followed by surgery.

Materials/Methods: This retrospective cohort study was conducted at a tertiary cancer centre in India and included all consecutive cases of rectal adenocarcinoma diagnosed between November 2018 and December 2022, with data censored as of October 31, 2024. Eligible patients had locally advanced rectal carcinoma and were aged =50 years. SCRT was delivered at a dose of 25 Gy in 5 fractions over one week, targeting the primary rectal lesion and the pelvic nodal region. Following SCRT, all patients received four cycles of chemotherapy (FOLFOX) before undergoing imaging for resectability assessment. Surgery was scheduled after the 4th, 8th, or 12th chemotherapy cycle, with any remaining cycles completed postoperatively to achieve a total of 12 cycles. Survival and recurrence data were retrospectively collected from electronic medical records, and follow-up for patients lost to contact was conducted via telephone. Statistical analyses were performed using statistical software.

Results: A total of 60 patients were identified, with a median age of 40.5 years (IQR: 34–46), and the youngest patient being 21 years old. The cohort included 37 males (61.7%) and 23 females (38.3%). The mean baseline CEA was 32.64 ng/mL with a standard deviation of 99.62. Baseline circumferential resection margin (CRM) involvement was present in 36 patients (60%). Tumor location was distributed as follows: upper rectum in 12 patients (20%), middle rectum in 14 patients (23.3%), and lower rectum in 34 patients (56.7%). Disease staging revealed stage 2 in 5 patients (8.3%), stage 3 in 44 patients (73.3%), and stage 4 in 11 patients (18.3%). A total of 37 patients (61.7%) underwent surgery after completing four cycles of chemotherapy, with the remaining eight cycles administered postoperatively. A pathological complete response (pCR) was observed in 21 patients (35%) following surgery. Among the 60 patients, 48 (80.0%) had no recurrence. The remaining 12 patients (20.0%) experienced distant recurrence at various sites: 1 each in the liver, mediastinal nodes, anterior abdominal wall, lung, and inguinal lymph node; 3 in the brain; and 2 in the peritoneum and 2 with multisite involvement. None of the patients had local recurrence. Median follow-up time is 33 months and the estimated three-year survival rate is 84.7%.

Conclusion: In rectal cancer patients under 50, SCRT followed by chemotherapy resulted in higher pCR, no local recurrences, and survival comparable to standard treatment approaches.