Long-Term Outcome of Patients with Complete Pathologic Response after Neoadjuvant Chemoradiation for cT3 Rectal Cancer: Implications for Local Excision Surgical Strategies

BACKGROUND: Neoadjuvant chemoradiotherapy (CRT) followed by radical surgery including total mesorectal excision (TME) is standard treatment in patients with locally advanced rectal cancer. Emerging data indicate that patients with complete pathologic response (ypCR) after CRT have favorable outcome, suggesting the possibility of less invasive surgical treatment. We analyzed long-term outcome of cT3 rectal cancer treated by neoadjuvant CRT in relation to ypCR and type of surgery. METHODS: The study population comprised 139 patients (93 men, 46 women; median age 62 years) with cT3N0–1M0 mid and distal rectal adenocarcinoma treated by CRT and surgery (110 TME and 29 local excision) at our institution between 1996 and 2008. At pathology, ypCR was defined as no residual cancer cells in the primary tumor. RESULTS: Tumors of 42 patients (30.2%) were classified as ypCR. After a median follow-up of 55.4 months, comparing patients with ypCR to patients with no ypCR, 5-year disease-specific survival was 95.8% versus 78.0% (P = 0.004), and 5-year disease-free survival was 90.1% vs. 64.0% (P = 0.004). In patients with ypCR, no statistically significant outcome difference was observed between TME and local excision. In patients treated by local excision, comparing patients with ypCR to patients with no ypCR, 5-year disease-free survival was 100% vs. 65.5% (P = 0.024), and 5-year local recurrence-free survival was 92.9% vs. 66.7% (P = 0.047). CONCLUSIONS: With retrospective analysis limitations, our data confirm favorable long-term outcome of cT3 rectal cancer with ypCR after CRT and warrant clinical trials exploring local excision surgical strategies.