Abstract 100P
Background
Positive Circumferential resection margin (CRM) could lead to incomplete resection at surgery, and is robust predictor of locoregional control (LRC) in carcinoma rectum patients. This study evaluates the efficacy SCRT in patients with CRM positivity.
Methods
This retrospective study was conducted at a tertiary care oncology centre in North India between 2019 to 2022. The censoring date was 30th June 2024. Patients were eligible if they were aged older than 18 years, had ECOG of 0–2, with a newly diagnosed, non-metastatic rectal adenocarcinoma with CRM positivity, nodal or primary, on the baseline MRI. These patients received SCRT, 25Gy in 5 fractions over one week. After 1 week, the patient received neoadjuvant FOLFOX chemotherapy (CT) for a total of 4-12 cycles, and based on MR-TRG, surgery was planned, at the end of 4, 8 or 12 cycles of CT (TNT). The remaining cycles were administered in the adjuvant setting. Patients who completed the treatment protocol including surgery were selected. The primary end points were pathological CRM (pCRM), pathological complete response (pCR), loco-regional recurrence (LRR) and overall survival (OS).
Results
Upon retrospective analysis of the institutional database, a total of 202 carcinoma rectum patients who received SCRT were identified, out of which 103 (50.99%) patients had a positive CRM on baseline MRI. CRM positivity due to primary disease was observed in 53 (51.45%) patients, whereas, the remaining 50 (48.54%) were CRM positive due to nodal disease. All these patients received CT, however, 62 (60.19%) patients completed the entire treatment protocol at the study institute. The remaining patients either did not undergo surgery, or underwent surgery at another institute. Median follow-up was 23.88 months. Among the 62 evaluated patients, 59 (95.16%) had negative pCRM status, and 3 (4.84%) had a persistent positive pCRM. pCR was achieved in 18 patients (29.03%). LRR-free survival was 100%, however, one (0.016%) patient had distant failure. The OS rate at last follow-up was 94.12%.
Conclusions
SCRT in combination with TNT is a feasible approach, yielding higher pCR rates, with lower recurrences in CRM positive patients. Further real world data are required.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.