Is neoadjuvant chemoradiotherapy necessary for locally advanced rectal cancer above the anterior peritoneal...

To define anterior peritoneal reflection (APR) as a more reasonable boundary for upper rectal cancer (URC) and assess the effect of neoadjuvant chemoradiotherapy (CRT) on locally advanced rectal cancer (LARC) above the APR.

MRI identified patients with LARC above the APR, excluding T4b cases. Patients were grouped by CRT status, and differences in their treatments and outcomes were compared. Propensity score matching was applied to adjust for baseline differences.

Of 1869 patients, 1702 (91.1%) had visible APR, with median heights of 7.5 cm for females and 8.6 cm for males. From 2011 to 2018, 479 patients with LARC above the APR were included. No significant differences were found between CRT and non-CRT groups in disease-free survival (DFS) (76.9% vs. 79.5%, P = 0.629), local recurrence-free survival (LRFS) (93.6% vs. 90.4%, P = 0.353) and overall survival (OS) (88.5% vs. 87.8%, P = 0.722). Cox regression showed CRT was not an independent influencing factor for DFS or OS.

It was feasible to accurately identify APR using MRI and distinguish upper and lower rectal cancer. CRT might not be essential for LARC patients above the APR after excluding T4b cases, which can avoid unnecessary treatment.