Multidisciplinary management of colorectal adenocarcinoma associated with anal fistula: an Indian series.

Aim: Adenocarcinomas associated with anal fistula are rare and often present at an advanced stage. They are often mistaken for commonly occurring benign diseases, leading to delayed diagnosis. Previous reports have predicted inferior oncological outcomes for these cases compared with sporadic rectal cancers. We are presenting our series of patients with colorectal adenocarcinoma associated with anal fistula who were treated with multimodality therapy at a tertiary cancer centre in India.

Method: This was a retrospective review of a prospectively maintained database of patients treated at our centre between 1 July 2013 and 31 March 2015. Of the 15 patients included in the study, 11 had prior intervention in the form of seton placement or fistulotomy. Fourteen patients had circumferential resection margin (CRM) involvement at initial workup and hence were given neoadjuvant chemoradiotherapy (NACRT). None of the patients had distant metastasis and only 15% had regional nodal involvement.

Results: All 13 patients included in the final analysis underwent abdominoperineal excision (APE). Ten patients (73%) underwent extralevator APE. Plastic reconstruction in the form of a V-Y advancement flap for perineal closure was required in six patients (46%). On histopathological examination, a mucinous component was found to be present in 11 patients (73%). The quality of total mesorectal excision was complete in 92% patients. The CRM was free in 92% of patients. Median overall survival and disease-free survival were not reached.

Conclusion: Colorectal adenocarcinomas associated with fistula are locally aggressive malignancies with a low incidence of lymph node involvement and distant metastasis. NACRT, wider resection in the form of extralevator APE, and liberal use of plastic reconstruction may result in favourable outcomes.