Long-Term Outcome of Rectal Cancer With Clinically (EUS/MRI) Metastatic Mesorectal Lymph Nodes Treated by Neoadjuvant Chemoradiation: Role of Organ Preservation Strategies in Relation to Pathologic Response

Organ preservation strategies are under investigation for patients with locally advanced rectal cancer (LARC) who achieve a complete pathologic response in the primary tumor (ypT0) after neoadjuvant chemoradiation therapy (CRT). This study explored the value of this approach for cN+ patients. Data were retrieved from our institutional prospective rectal cancer database. Tumors with mesorectal lymph nodes larger than 5 mm shown on endorectal ultrasonography, pelvic magnetic resonance imaging, or both were staged as cN+. The study population comprised 226 patients (142 men and 84 women; median age, 64 years) with LARC who underwent CRT followed by surgery including total mesorectal excision (TME) (n = 179) and full-thickness local excision (LE) (n = 47) between 1996 and 2013. At staging, 123 patients (54.4 %) were cN+. In 65 cases (28.7 %), ypCR was observed. Metastatic mesorectal lymph nodes (ypN+) were detected in 41.6 % of the cN+ patients and in 2.8 % of the cN0 patients (P < 0.01). Among the cN+ patients, 16 % of the ypT0 cases were ypN+ compared with 51.8 % of the no-ypT0 cases (P < 0.01). Among the cN+ patients who underwent TME, the 5-year disease-specific survival (DSS) and disease-free survival (DFS) rates were respectively 100 and 91.6 % for the ypT0 patients compared with 71.2 and 58.0 % for the no-ypT0 patients (P = 0.01). Among the ypN+ patients, the 5-year DSS and DFS rates were both 100 % for the ypT0 cases compared with 59.1 and 43.3 % for the no-ypT0 patients. Among the cN+ and ypT0 patients, the 5-year DSS and DFS were respectively 100 and 85.7 % for the TME patients compared with 100 and 91.6 % for the LE patients. In the multivariate analysis, ypT0 was the only independent prognostic factor. Protocols aimed at organ preservation in LARC that achieve ypT0 after CRT can be offered also to cN+ patients.