Watch-and-wait versus surgical resection for patients with rectal cancer

Abstract

e132 www.thelancet.com/oncology Vol 17 April 2016 The most important prognostic factor in rectal cancer treatment is circumferential margin. The OnCoRe authors refer to the MERCURY study. The MERCURY study had patients with very heterogeneous tumours and treatment stages. 182 (49%) of 374 patients in the study had N+ tumours. 5-year disease-free survival was 67% for patients with a clear circumferential resection margin judged by MRI, compared with 47% for patients with an involved circumferential margin (p=0·003). 5-year survival rates were different when the pathological circumferential resection margin was used. 5-year overall survival was 63·3% in patients with a clear pathological circumferential resection margin and 30·2% in those with an involved margin (p=0·001). The OnCore study did not mention pathological circumferential resection margin in either treatment group and should have discussed circumferential resection margin status. Colostomy-free survival might not extend overall survival because we do not know the circumferential resection margin positivity in the OnCoRe project, which aff ects survival in rectal cancer.