Utility of Rectoscopy in the Assessment of Response to Neoadjuvant Treatment for Locally Advanced Rectal Cancer

BACKGROUND/AIMS: The management of locally advanced rectal cancer has changed substantially over the last few decades with neoadjuvant chemoradiotherapy. The aim of the present study is to compare the results between neoadjuvant post-treatment rectoscopy and the anatomopathological findings of the surgical specimen. PATIENTS AND METHODS: We conducted a prospective study of 67 patients with locally advanced adenocarcinoma of the rectum (stages II and III). Two groups were established: One with complete clinical response (cCR) and one without (non-cCR), based on the findings at rectoscopy. Assessment of tumor regression grade in the surgical specimen was determined using Mandard's tumor regression scale. RESULTS: Seventeen patients showed a cCR. Thirty-five biopsies were negative and 32 were positive for mailgnancy. All the cCR patients had a negative biopsy (P < 0.0001). All 32 positive biopsies revealed the presence of adenocarcinoma, and of the 35 negative biopsies, 18 had no malignancy and 17 were diagnosed with adenocarcinoma (P < 0.0001). Sixteen of the 17 cCR patients showed a complete pathological response and one patient showed the presence of adenocarcinoma. Of the 50 non-cCR patients 48 revealed the presence of adenocarcinoma and two had absence of malignancy. According to the Mandard classification, 16 of the 17 cCR patients were grade I and 1 grade II; 2 non-cCR patients were grade I, 7 grade II, 13 grade III, 19 grade IV, and 9 grade V. CONCLUSIONS: Endoscopic and histological findings could be determinants in the assessment of response to neoadjuvant treatment.