Prognostic value of pathological nodal status and tumor regression grade in patients with rectal cancer (RC) treated with pre-operative chemoradiotherapy

Abstract

13524 Background: The main objective of this study is to clarify the correlation between pathological nodal status and Dworak tumor regression grade (TRG) (Dworak et al. Int Colorectal Dis 1997, 12:19–23) after pre-operative chemoradiotherapy. Methods: From May 1998 to February 2005, 112 patients with locally advanced rectal cancer were diagnosed at Centro Oncologico Modenese and treated with pre-operative concomitant pelvic irradiation (50 Gy in 25 fractions) and chemotherapy with 5-FU in continuous infusion (225 mg/msq/daily). We considered for our analysis only pathological stage III cases. Results: Clinical positive nodal status (by CT scan or ultrasonography) was present in 71 patients on 106 (66.9%) at diagnosis. Among all radically resected patients (106), pathologic assessment of lymph nodes in surgical specimens was performed; average number of nodes examined was 11 (range: 2–22). Thirty patients (28.3%) had a positive nodal status at pathological examination: 19 (63.3%) were pN1 (≤3 lymph nodes) and 11 (36.7%) were pN2 (>3). The nodal status changed from 66.9% (clinical evaluation) to 28.3% (pathologic evaluation). Among stage III patients 5 (16.7%) had a TRG 3, 12 (40%) TRG 2, 11 (36.7%) TRG 1 and 2 (6.6%) TRG 0. At a median follow-up of 32,3 months, 20/106 patients relapsed (18.8%); of these 20, 10 (50%) had a positive pathologic nodal status. In this subset recurrence occurred in 5/10 (50%) pN1 patients (1 local and 4 with distant metastases) and 5/10 (50%) pN2 patients (2 local and 3 with distant metastases). The 3-y DFS was 63% (68% pN1 and 54% pN2) (p=0.32). The 3-y OS was 84% (94% pN1 and 68% pN2, p=0.72). The 3-y DFS in post-operative stage III patients according to tumor regression grade was 81% for TRG 2–3 and 38% TRG 0–1 (p<0.026). Conclusions: In stage III patients, TRG is confirmed as a relevant prognostic factor in locally advanced rectal cancer treated with neo-adjuvant chemo-radiotherapy. In the same subset of patients the number of positive nodes seems to impact on the prognosis, even not reaching a significant relevance. No significant financial relationships to disclose.