Long-term outcomes of surgery alone versus surgery following preoperative chemoradiotherapy for early T3 rectal cancer A propensity score analysis

Recently, a few studies have raised the question of whether preoperative chemoradiotherapy (PCRT) is essential for all T3 rectal cancers. This case-matched study aimed to compare the long-term outcomes of surgery alone with those of PCRT+ surgery for magnetic resonance imaging (MRI)-assessed T3ab (extramural depth of invasion <= 5mm) and absent mesorectal fascia invasion (clear MRF) in mid/ lower rectal cancer patients. From January 2006 to November 2012, 203 patients who underwent curative surgery alone (n= 118) or PCRT+ surgery (n= 85) were enrolled in this retrospective study. A 1: 1 propensity score-matched analysis was performed to eliminate the inherent bias. Case-matching covariates included age, sex, body mass index, histologic grade, carcinoembryonic antigen, operation method, follow-up period, tumor height, and status of lymph node metastasis. The end-points were the 5-year local recurrence (LR) rate and disease-free-survival (DFS). After propensity score matching, 140 patients in 70 pairs were included. Neither the 5-year LR rate nor the DFS was significantly different between the 2 groups (the 5-year LR rate, P= 0.93; the 5-year DFS, P= 0.94). The 5-year LR rate of the surgery alone was 2% (95% confidence interval [CI] 0.2%-10.9%) versus 2% (95% CI 0.2%-10.1%) in the PCRT+ surgery group. The 5-year DFS of the surgery alone was 87% (95% CI 74.6%-93.7%) versus 88% (95% CI 77.8%-93.9%) in the PCRT+ surgery group. In patients with MRI-assessed T3ab and clear MRF mid/ lower rectal cancer, the long-term outcomes of surgery alone were comparable with those of the PCRT+ surgery. The suggested MRI-assessed T3ab and clear MRF can be used as a highly selective indication of surgery alone in mid/ lower T3 rectal cancer. Additionally, in those patients, surgery alone can be tailored to the clinical situation.