Background: The goals of this study were to characterize the variation in suboptimal lymph node examination for patients with colon cancer across individual surgeons, pathologists, and hospitals and to examine if this variation affects 5-year, disease-specific survival.
Methods: A retrospective cohort study was conducted by merging the New York State Cancer Registry with the Statewide Planning & Research Cooperative System, Medicaid, and Medicare claims to identify resections for stages I-III colon cancer from 2004-2011. Multilevel logistic regression models characterized variation in suboptimal lymph node examination (<12 lymph nodes). Multilevel competing-risks Cox models were used for survival analyses.
Results: The overall rate of suboptimal lymph node examination was 32% in 12,332 patients treated by 1,503 surgeons and 814 pathologists at 187 hospitals. Patient-level predictors of suboptimal lymph node examination were older age, male sex, nonscheduled admission, lesser stage, and left colectomy procedure. Hospital-level predictors of suboptimal lymph node examination were a nonacademic status, a rural setting, and a low annual number of resections for colon cancer. The percent of the total clustering variance attributed to surgeons, pathologists, and hospitals was 8%, 23%, and 70%, respectively. Increasing the pathologist and hospital-specific rates of suboptimal lymph node examination were associated with worse 5-year, disease-specific survival.
Conclusion: There was a large variation in suboptimal lymph node examination between surgeons, pathologists, and hospitals. Collaborative efforts that promote optimal examination of lymph nodes may improve prognosis for colon cancer patients. Given that 93% of the variation was attributable to pathologists and hospitals, endeavors in quality improvement should focus on these 2 settings.
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