NEOADJUVANT SHORT COURSE RADIATION THERAPY AND CHEMOTHERAPY IN LOCALLY ADVANCED RECTAL CANCER (SINGLE INSTITUTE STUDY)

Abstract

Objectives: To evaluate the clinical and pathological response after neoadjuvant short course radiation therapy followed by chemotherapy followed by Surgery in patients suffering from locally advance rectal adenocarcinoma.

Materials and Methods:  Patients with rectal and rectosigmoid adenocarcinoma at National University of Medical Sciences (NUMS) Tertiary care Hospital Rawalpindi were assessed, meeting criteria and discussed in a multi-disciplinary team. After consent, they underwent clinical examination and received 25 Gray (Gy) radiotherapy in 5 daily fractions, over one week, followed by six chemotherapy courses with Capecitabine and Oxaliplatin, then total mesorectal excision. Disease response was evaluated radiologically using RECIST criteria and histopathology reports. Data was collected via a questionnaire and analyzed with SPSS v 25.0.

Results: The mean age of all enrolled 27 patients was 53.00±8.03 years with mean tumor size of 3.92±0.87 cm. Out of total patients 17(63.0%) were male while the remaining 10(37.0%) were female. Among the patients, 2 (7.4%) were aged between 18 and 40 years, while 7 (25.9%) were between 41 and 50 years. The majority of the patients, 15 (55.6%), were in the 51 to 60 years age group. Additionally, 3 patients (11.1%) were older than 60 years. In this study, the mortality rate was 7.4%, with 2 patients having died, while 25 patients (92.6%) survived. Clinical down staging occurred in 22 patients (81.5%), while 5 patients (18.5%) did not experience down staging. The histopathological response category analysis showed that 14 patients (51.9%) had a complete response to treatment, 9 patients (33.3%) had a partial response, and 4 patients (14.8%) had no response. Stratification of response categories with respect to age groups, gender, and tumor size was done as: In terms of gender, 9 males (52.9%) achieved a complete response, 5 males (29.4%) had a partial response, and 3 males (17.6%) had no response. For females, 5 (50%) had a complete response, 4 (40%) had a partial response, and 1 (10%) had no response, with a P-value of 0.79. Regarding age groups, for those aged 18-40 years, 2 patients (14.3%) had a complete response, with no partial response or no response cases reported. In the 41-50 years age group, 3 patients (42.85%) had a complete response, 3 patients (42.85%) had a partial response, and 1 patient (14.3%) had no response. Among those aged 51-60 years, 9 patients (60.0%) had a complete response, 5 patients (33.33%) had a partial response, and 1 patient (6.67%) had no response. For patients over 60 years, none had a complete response, 1 patient (33.33%) had a partial response, and 2 patients (66.67%) had no response, with a P-value of 0.12. In terms of tumor size, patients with tumors less than 4 cm had a higher complete response rate (10 patients, 50.0%) and a partial response rate of 9 patients (45.0%), with only 1 patient (5.0%) showing no response. For tumors larger than 4 cm, 4 patients (80.0%) had a complete response, none had a partial response, and 1 patient (20.0%) had no response, with a P-value of 0.16.

Conclusion: It was concluded that neoadjuvant therapy is a valuable approach for treating locally advanced rectal cancer with no high risk features. This regimen presents a promising strategy for managing advanced cases and offers practical insights into the implementation of these treatments within a specific institutional context.