Comparative Effectiveness of Total Neoadjuvant Therapy Versus Standard Adjuvant Chemotherapy for Locally Advanced Rectal Cancer.

INTRODUCTION: The use of total neoadjuvant therapy (TNT) for locally advanced rectal cancer has been increasing in recent years, but the long-term overall survival characteristics of this approach is currently unknown. METHODS: We performed a retrospective study of patients with clinical stage II/III rectal cancer within the National Cancer Database. Patients who received TNT (defined as chemotherapy, followed by CRT, followed by surgery) were propensity score matched to patients who received adjuvant therapy (defined as CRT, followed by surgery, followed by chemotherapy). We compared overall survival (OS) and rates of pathologic complete response (pCR) between the 2 arms. RESULTS: Of the 4300 patients in our cohort, 3502 (81%) received adjuvant therapy and 798 (19%) received TNT. At baseline, patients who received TNT were more likely to have higher clinical T and N stages (P< .001). The 5-year OS was 77% for both TNT and adjuvant therapy patients (hazard ratio [HR] 1.06, 95% confidence interval [CI], 0.88-1.28, P = .57). After propensity score matching and adjusting for potential confounders, there were no significant differences in OS (HRadj 1.00, 95% CI, 0.71-1.40, P = .99). After propensity score matching, there were higher pCR rates among TNT patients (16.1%) compared to adjuvant therapy patients (12.0%) (P = .037). CONCLUSION: In this observational study, we found TNT was not associated with a lower OS compared to standard adjuvant chemotherapy. This finding potentially reassures clinicians choosing TNT as an alternative to adjuvant chemotherapy. However, future prospective data are needed to confirm these findings.

Implications of Lymph Node Staging on Selection of Adjuvant Therapy for Gastric Cancer in the United States: A Propensity Score-matched Analysis.

OBJECTIVE: To compare the efficacy of adjuvant chemoradiotherapy (CRT) and chemotherapy alone (CA) in gastric adenocarcinoma patients undergoing gastrectomy in the United States (US). BACKGROUND: A majority of US gastric adenocarcinoma patients are inadequately staged (<15 nodes examined). Despite this, and limited data comparing adjuvant CRT with CA in US patients, national guidelines endorse CA in selected patients undergoing D2 lymphadenectomy. METHODS: Resected stage IB-III gastric adenocarcinoma patients receiving adjuvant CRT or CA (n = 3008) were identified in the National Cancer Database (1998-2006). Cox regression identified covariates associated with overall survival (OS). CRT and CA cohorts were matched (3:1) by propensity scores based on the likelihood of receiving CA. OS was compared by Kaplan-Meier estimates. RESULTS: Adjuvant CA was associated with an increased risk of death (HR 1.29, P < 0.001) relative to CRT. Inadequate lymph node staging (LNS) and nodal positivity were strong predictors of risk-adjusted mortality (P < 0.001). After propensity score-matching, CRT demonstrated superior median OS compared with CA (36.1 vs 28.9 m; P < 0.0001), regardless of stage. CRT was superior to CA in inadequately staged patients (33.1 m vs 24.5 m; P < 0.001); this benefit was less pronounced with increasing nodal examination. CRT improved OS in node-positive disease (29.8 vs 22.2 m; P < 0.001), regardless of LNS adequacy. In node-negative disease, OS did not differ significantly between CRT and CA cohorts; however, node-negative patients undergoing inadequate LNS benefited from CRT. CONCLUSIONS: CRT is associated with improved stage-stratified OS compared with CA. Lymph node status and adequacy of surgical staging should influence adjuvant therapy selection in the United States.