Outcome of neoadjuvant chemoradiation in MRI staged locally advanced rectal cancer: Retrospective analysis of 123 Chinese patients.

BACKGROUND: For advanced rectal cancer with involved or threatened mesorectal fascia (MRF), current standard is pre-operative long course chemoradiotherapy (PLCRT) with either capecitabine or 5-fluorouracil (5-FU). However, few Chinese data on its clinical outcome are available, especially for those with pelvic MRI staging.

METHODS: Between Jan-2009 and Oct-2014, 123 consecutive patients with biopsy proven adenocarcinoma of rectum, all with pelvic MRI staging, selected for PLCRT after multi-disciplinary team discussion were recruited. Their clinical records were retrospectively reviewed.

RESULTS: Median follow-up was 1392 days (range: 48-2886) MRI defined poor risk factors as follows: MRF threatened or involved ≤1 mm 61.8% (n = 76), cT4 13.8% (n = 17), cN2 26.8% (n = 33) and low-lying tumor (≤5 cm from anal verge) 24.4% (n = 30). Five year OS and DFS were 63.9% and 68.3% respectively. Among 112 patients who received TME, 108 (96.4%) had microscopic clear resection (R0). Twelve and 32 individuals had pathological complete response and ypT0-2N0, respectively. Five local recurrences (4.5%) were detected. The incidence of grade 3 or above acute and late radiotherapy toxicity was 8.1% and 12.2% respectively. After multivariate adjustment, positive circumferential resection margin (CRM) status on pathology report was found to be significant factor for worse OS and DFS.

CONCLUSION: The clinical outcomes of PLCRT in our institution are comparable with those in western literature. Our MRI staging lends support to the validity of data. CRM status is the most significant prognostic factor in OS and DFS, after multivariate adjustment.