Pathologic Complete Remission after Preoperative Chemoradiation for Rectal Cancer: Analysis of Clinicopathologic Characteristics and Oncologic Outcome

ABSTRACT

PURPOSE: To assess the clinico-pathologic characteristics associated with pathologic complete remission (pCR) after preoperative chemoradiotherapy (PCRT) for rectal cancer and evaluate predictive factors for pCR and prognostic impact of pCR. METHODS: We analyzed 325 patients who underwent PCRT and surgical resection between September 1999 and September 2006. We have treated 319 patients with PCRT for locally advanced rectal cancer and 6 patients for sphincter-saving procedure. Chemotherapy consisted of either of bolus 5-FU (325 mg/m2/d) or capecitabine (1,650 mg/m2/d) for the duration of radiation and after surgery. Radiation therapy was delivered and surgery was performed 4~6 weeks following the completion of PCRT. We compared pCR patients with non-pCR patients according to the clinico-pathologic characteristics and followed up with a median of 32 (range, 12~91) months. RESULTS: The pCR (n=41, 12.6%) and non-pCR (n=284) groups were comparable in age, sex, location of the tumor, chemotherapy regimen, pre-CRT CEA level except pre-CRT clinical stage (12.2% vs. 0.4% in stage I, P= 0.047). There was no significant difference in genetic characteristics between groups. There was no specific predictive factors for pCR except pre-CRT T category (pCR in T2 (5/8, 62.5%) vs. T3 (33/283, 11.7%) or T4 (3/33, 9.1%), P=0.001). The 3-year disease free survival (DFS) was 100% and 83.6% in the pCR and non-pCR group respectively (P=0.012). There were 5 local and 34 systemic recurrences only in non-pCR group. CONCLUSIONS: Rectal cancer patients with pCR after PCRT have an excellent prognosis and are unlikely to fail locally or systemically because of the effect of stage. However there was no specific predictive factor for pCR except preoperative T category.