Pushing the envelope beyond a centimeter in rectal cancer: Oncologic implications of close but negative margins.

Abstract

487 Background: Advances in surgery, adjuvant therapy and understanding of the natural history of rectal cancer has enabled sphincter preservation surgery for most patients. A 1 cm margin is commonly accepted as minimal distal margin, when not achievable many are relegated to permanent colostomy. Our purpose was to determine if distal margins of < 1 cm is justified by the world's published experience. Methods: Studies were identified with a MEDLINE search using terms rectal cancer, colorectal cancer, margins and distal margins with an additional manual search. There were no restrictions on data type or year of publication. All studies were retrospective or prospective, none were randomized controlled. Studies were excluded if specific margins, local recurrence rates or case level data could not be extracted. Extracted variables included year of publication, time span, number of patients, standardized surgery, radiotherapy, margins, follow up, local recurrence rates and overall survival. Meta-analysis was performed using a random weighting scheme. Values were aggregated across studies to determine overall impact and p-values. Results: Seventeen studies reported margins with thirteen studies, 3,232 patients, reporting outcomes when < 1cm. Meta-analysis of all studies indicated a nonsignificant trend favoring greater margins. However, in order to understand distal margins in the context of current standards additional analyses were performed. Of the thirteen studies 4 reported neither TME nor use adjuvant radiotherapy and 9 studies reported use of one or both. When either total mesorectal excision and/or adjuvant radiotherapy was reported there was no significant increase in local recurrence with distal margins < 1 cm. In studies that used neither therapy > 1 cm margins were statistically less prone to recurrence. Conclusions: Sphincter preservation is possible with < 1 cm distal margin when optimal surgical and adjuvant therapy are applied. [Table: see text]