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Background: Nodal status has long been considered pivotal to oncologic care, staging, and management. This has resulted in the establishment of rudimentary metrics regarding adequate lymph node yield in colon and rectal cancers for accurate cancer staging. In the era of neoadjuvant treatment, the implications of lymph node yield and status on patient outcomes remains unclear. Patient and Methods: This study included 1,680 patients with locally advanced rectal cancer from the NCCN prospective oncology database stratified into 3 groups based on preoperative therapy received: no neoadjuvant therapy, neoadjuvant chemoradiation, and neoadjuvant chemotherapy. Clinicopathologic characteristics and survival were compared between the groups, with univariate and multivariate analyses undertaken. Results: The clinicopathologic characteristics demonstrated statistically significant differences and heterogeneity among the 3 groups. The neoadjuvant chemoradiation group demonstrated the statistically lowest median lymph node yield (n=15) compared with 17 and 18 for no-neoadjuvant and neoadjuvant chemotherapy, respectively (P<.0001). Neoadjuvant treatment did impact survival, with chemoradiation demonstrating increased median overall survival of 42.7 compared with 37.3 and 26.6 months for neoadjuvant chemotherapy and no-neoadjuvant therapy, respectively (P<.0001). Patients with a yield of fewer than 12 lymph nodes had improved median overall survival of 43.3 months compared with 36.6 months in patients with 12 or more lymph nodes (P=.009). Multivariate analysis demonstrated that neither node yield nor status were predictors for overall survival. Discussion: This analysis reiterates that nodal yield in rectal cancer is multifactorial, with neoadjuvant therapy being a significant factor. Node yield and status were not significant predictors of overall survival. A nodal metric may not be clinically relevant in the era of neoadjuvant therapy, and guidelines for perioperative therapy may need reconsideration.

Based on randomized data, neoadjuvant chemoradiotherapy has been incorporated into the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for stage II-III rectal cancer. Factors associated with nonadherence to evidence-based guidelines for neoadjuvant radiotherapy (RT) were examined at dedicated cancer centers. The prospective NCCN Oncology Outcomes Database for Colorectal Cancers was queried for patients with stage II-III rectal cancer who underwent a transabdominal surgical resection between September 2005 and June 2012. Multivariable logistic regression was used to identify factors associated with omission of RT. Among 1199 identified patients, 1119 (93%) received neoadjuvant RT, 51 (4%) did not receive RT, and 29 (2%) received adjuvant RT. Among 51 patients not receiving RT, only 19 (37%) were referred and evaluated by a radiation oncologist. On multivariable analysis, clinical factors associated with not receiving RT included a history of prior pelvic RT (adjusted odds ratio [aOR], 23.9; P=.0003), ECOG performance status of 2 or greater (aOR, 11.1; P=.01), tumor distance from the anal verge greater than 10 cm (aOR, 5.4; P=.009), age at diagnosis of 75 years or older (aOR, 4.43; P=.002), body mass index of 25 to 30 kg/m² and less than 25 kg/m² (aOR, 5.22 and 4.23, respectively; P=.03), and clinical stage II (aOR, 2.27; P=.02). No significant change was seen in RT use according to diagnosis year, nor was any correlation seen with distance to the nearest RT facility. Concordance with NCCN Guidelines for neoadjuvant RT is high among NCCN Member Institutions. After adjusting for clinical characteristics that increase the risk for RT toxicity, including history of pelvic RT and high comorbidity burden/low functional status, the authors found that non-obese patients of advanced age or those with more favorable clinical features were more likely to not receive RT.