Association between neoadjuvant chemoradiation and survival for patients with locally advanced rectal cancer

To examine the overall survival differences for the following neoadjuvant therapy modalities - no therapy, chemotherapy alone, radiation alone and chemoradiation - in a large cohort of patients with locally advanced rectal cancer.

Adults with clinical Stage II and III rectal adenocarcinoma were selected from the National Cancer Database and grouped by type of neoadjuvant therapy received: no therapy, chemotherapy only, radiotherapy only or chemoradiation. Multivariable regression methods were used to compare adjusted differences in perioperative outcomes and overall survival.

Among 32 978 patients included, 9714 (29.5%) received no neoadjuvant therapy, 890 (2.7%) chemotherapy only, 1170 (3.5%) radiotherapy only and 21 204 (64.3%) chemoradiation. Compared with no therapy, chemotherapy or radiotherapy alone were not associated with any adjusted differences in surgical margin positivity, permanent colostomy rate or overall survival (all P > 0.05). With adjustment, neoadjuvant chemoradiation vs no therapy was associated with a lower likelihood of surgical margin positivity (OR 0.74, P < 0.001), decreased rate of permanent colostomy (OR 0.77, P < 0.001) and overall survival [hazard ratio (HR) 0.79, P < 0.001]. When compared with chemotherapy or radiotherapy alone, chemoradiation remained associated with improved overall survival (vs chemotherapy alone HR 0.83, P = 0.04; vs radiotherapy alone HR 0.83, P < 0.019).

Neoadjuvant chemoradiation, not chemotherapy or radiotherapy alone, is important for sphincter preservation, R0 resection and survival for patients with locally advanced rectal cancer. Despite this finding, one-third of patients in the United States with locally advanced rectal cancer fail to receive stage-appropriate chemoradiation.