Complete pathological response after neoadjuvant therapy in patients with rectal adenocarcinoma

Background

Colorectal cancer is the fourth most common cancer and the second leading cause of death from cancer in the United States. Preoperative neoadjuvant therapy (chemotherapy and radiotherapy) is the gold standard in the management of rectal cancer before surgical resection. The literature includes reports of absence of neoplastic cells after neoadjuvant therapy. There are no reports on complete pathological response to this type of therapy in Mexico.

Objectives

Determine the percentage of patients with rectal adenocarcinoma with complete pathological response after neoadjuvant therapy. All patients were treated in a colorectal surgery department of a tertiary care hospital.

Materials and methods

A total of 64 patients with rectal adenocarcinoma diagnosed by biopsy were treated from January 2010 to December 2015. Demographic data, tumour localisation, pathological report, TNM stage, neoadjuvant therapy, surgical procedure and postoperative pathological report were collected from patient records.

Results

Mean patient age was 52.8 years (range of 26–73); 31 were women and 33 men. Twenty-seven patients (27) were stage II and 27 stage III. The preoperative biopsy results were classified as: well differentiated (10); moderately differentiated (48); and poorly differentiated/undifferentiated adenocarcinoma (6). Twenty patients received neoadjuvant therapy (31.2%). In these, 2 tumours were localised in the upper third of the rectum, 6 in the middle third, and 12 in the lower third. Six patients underwent abdominoperineal resection, 10 total mesorectal excision, and four posterior pelvic exenteration. Six patients undergoing neoadjuvant therapy had a complete pathological response.

Conclusions

The percentage of patients with a complete pathological response is similar to that in other literature reports. More evidence is needed to define good prognosis factors in patients who might not require surgery after neoadjuvant therapy.