Impact of surgical staging for aggressive histology rectal cancers: a retrospective review.

Abstract

Poorly differentiated adenocarcinomas and signet ring adenocarcinomas are aggressive histological subtypes of rectal cancer with a high incidence of occult peritoneal metastasis. This was a retrospective review of aggressive histology of rectal cancer patients who underwent pre-treatment surgical staging as part of ovarian transposition or ostomy creation for diversion at a single tertiary cancer centre between January 2014 and December 2019. A total of 117 patients underwent surgical staging and were deemed non-metastatic on imaging. Surgical staging led to the detection of metastasis in 29.9% of patients. This led to modification in treatment protocol in 20.5% and change in intent of therapy in 15.4%. The majority (80%) was found to have peritoneal disease with peritoneal carcinomatosis index <17. Only T4 disease predicted the presence of metastasis on surgical staging with an odds ratio of 2.69 (P = 0.035). A significant proportion of patients with aggressive histology rectal cancers are upstaged after surgical staging. Further investigation of this tool for staging is warranted.