Endoscopic ultrasound for rectal cancer staging: A population-based study of utilization, impact on treatment patterns, and survival

Background and Aim: Optimal rectal cancer (RC) outcomes depend on accurate locoregional staging. The study sought to describe the impact of endoscopic ultrasound (EUS) on RC treatment patterns and survival. Methods: Using the Surveillance, Epidemiology, and End Results-Medicare database, the study identified patients with RC between 2005 and 2007. The study excluded patients with stage IV disease, those not enrolled in Medicare parts A and B, those enrolled in managed care, and those staged with pelvic magnetic resonance imaging (because of low numbers). The study then compared outcomes between patients who received EUS and computed tomography of the abdomen and pelvis (CTAP) to those staged with CTAP alone after propensity score matching. Results: Between 2005 and 2007, we identified 3,408 nonmetastatic RC patients. Compared with patients staged with CTAP alone, those who received EUS and CTAP were younger (median age: 75 vs 76 years, P < 0.0001), more likely men (57.6% vs 48.7%, P < 0.0001), with a lower Charlson comorbidity index (P < 0.0001). Predictors of EUS included socioeconomic status (highest vs lowest) (odds ratio [OR] 1.87, 95% confidence interval [CI] 1.4-2.5), care by a gastroenterologist (OR 1.713, 95% CI 1.38-2.13), and care in a teaching hospital (OR 1.68, 95% CI 1.35-2.08). Receipt of neoadjuvant chemoradiation was higher in EUS-staged patients (50.3% vs 16.0%, P < 0.0001). EUS-staged patients had longer overall survival compared with those staged with CTAP alone (60 vs 57 months), but this was not statistically significant (P = 0.24). Conclusion: Endoscopic ultrasound in RC staging is associated with higher utilization of neoadjuvant chemoradiation without a significant difference in overall survival.