Response to neoadjuvant therapy for rectal cancer: influence on long-term results

Pre-operative treatment with chemoradiotherapy (CRT) seems to improve local control and overall survival in patients with rectal cancer. The aims of the study were to analyse the impact on overall, disease free and cancer related survival of tumour response to pre-operative CRT and to analyse the influence of the degree of response on long-terms results.

Patients with a locally advanced rectal cancer, treated by pre-operative CRT were studied. A radical resection of the rectal tumour with mesorectal excision was performed within 6-8 weeks. Judged on the final TNM classification patients were considered responders when the tumour showed histologically a complete response, microscopic residual disease or a partial response. Non-responders were those in whom the extent of disease remained stable or progressed. Results Radical excision was performed in 103 patients, and a palliative resection in five. Forty-three patients underwent abdominoperineal resection and 65 anterior resection of the rectum. Seventy-one (65.7%) patients showed a response to CRT, while 37 (34.3%) did not. The overall local and distant recurrence rates were 6.8% and 21.3%. Tumour recurrence (P < 0.008) and disease free survival (P < 0.007) were significantly different in responders and nonresponders. Of the 71 responders, 16 had a pathological complete response, 27 had persisting microscopic disease and 28 had macroscopic residual disease. No differences in cancer specific outcome were observed in these groups.

Pathological response to pre-operative CRT is associated with improved tumour recurrence and disease-free survival rates. Any response to pre-operative CRT appears to improve outcomes as much as a complete response.