Radiotherapy after local excision of rectal cancer may offer reduced local recurrence rates

Abstract

Aim: Early rectal cancer can be managed effectively with local excision, which is now the standard of care for many T1 lesions. However, the presence of unexpected adverse histopathological factors may indicate an increased risk of local recurrence, prompting consideration of completion radical surgery. Many patients are unfit or prefer to avoid radical surgery, relying instead on surveillance and early detection of recurrent disease. Recently, radiotherapy has shown promise as an adjuvant therapy in this group. This study assesses local recurrence rates after local excision with adjuvant radiotherapy at a single centre.

Method: This was a retrospective review of a prospective database of all patients undergoing transanal endoscopic microsurgery (TEM) in a single institution. Data covering a 10-year period were analysed.

Results: Of 197 patients undergoing TEM for rectal cancer, 33 (17%) had adjuvant radiotherapy because of adverse histopathological features. At 3.2 years' median follow-up, there were three instances of local recurrence (9.1%). Estimated local recurrence at 1 and 3 years was 0% and 6.9%, compared to 16.8% and 21.2% in a propensity-score-matched group who were followed by surveillance alone. Local recurrence was diagnosed at a median of 23 months post-TEM in the radiotherapy group, compared to 8 months in the matched group.

Conclusion: Radiotherapy after TEM is associated with a trend towards a reduced rate of local recurrence, even for high-risk disease. Radiotherapy would appear to offer a viable alternative to radical completion surgery in the presence of unforeseen adverse histopathological features, as long as a meticulous surveillance programme is in place.

Keywords: Rectal cancer; TEM; adjuvant radiotherapy; local excision; local recurrence.