Quality of care along the cancer continuum: Does receiving adequate lymph node evaluation for colon cancer lead to comprehensive postsurgical care?

Among surgically treated patients with colon cancer, lower long-term mortality has been demonstrated in those with 12 or more lymph nodes evaluated. We examined whether patients receiving adequate lymph node evaluation were also more likely to receive comprehensive postsurgical care, leading to lower mortality. We used the 1992 to 2007 Surveillance, Epidemiology, and End Results (SEER)-Medicare data to identify surgically treated American Joint Committee on Cancer (AJCC) stage III colon cancer patients. We used chi-square analyses and logistic regression to evaluate the association between adequate (<12) lymph node evaluation and receipt of postsurgical care (adjuvant chemotherapy, surveillance colonoscopy, CT scans, and CEA testing) and Cox proportional hazards regression to evaluate 10-year all-cause mortality, adjusting for postsurgical care. Among 17,906 surgically treated stage III colon cancer patients, adequate (<12) lymph node evaluation was not associated with receiving comprehensive postsurgical care after adjustment for patient and tumor characteristics (p > 0.05 for all). Initially, adequate lymph node evaluation was associated with lower all-cause mortality (hazard ratio [HR] 0.88; 95% CI [0.85 to 0.91]), but among 3-year survivors, the impact of adequate lymph node evaluation on lower mortality was diminished (HR 0.94; 95% CI [0.88 to 1.01]). However, receiving comprehensive postsurgical care was associated with continued lower mortality in 3-year survivors. Adequate lymph node evaluation for colon cancer was associated with lower mortality among all patients. However, among 3-year survivors, the association between lymph node evaluation and lower hazard of death was no longer significant, while postsurgical care remained strongly associated with lower long-term mortality, indicating that postsurgical care may partially explain the relationship between lymph node evaluation and mortality.