Hypothesis: The improved survival after esophageal cancer surgery in Sweden during recent years may be attributable to the increased centralization of such surgery.
Design: Population-based study.
Setting: All Swedish residents undergoing esophageal cancer surgery from January 1, 1987, through December 31, 2000, were identified from the inpatient and cancer registers and were followed up until October 18, 2004, through nationwide registers. Hospital, tumor, and patient characteristics and preoperative oncological treatment were assessed through the registers and histopathological records.
Patients: Among 4904 patients with esophageal cancer, 1199 patients (24.4%) who underwent resection constituted the study cohort. Main Outcome Measure Survival rates and hazard ratios (HRs) relative to hospital volume. Low-volume hospitals (LVHs) conducted fewer than 10 esophagectomies annually, while high-volume hospitals (HVHs) conducted 10 or more. Hazard ratios were adjusted for several potential confounders.
Results: Thirty-day survival was 96% at HVHs and 91% at LVHs (P = .09). Survival rates 1, 3, and 5 years after surgery at HVHs were nonsignificantly higher (58%, 35%, and 27%, respectively) compared with those at LVHs (55%, 30%, and 24%, respectively). The adjusted HR was nonsignificantly 10% decreased at HVHs (HR, 0.90; 95% confidence interval, 0.79-1.04). In an analysis restricted to 764 patients (64%) without preoperative oncological treatment (in which the tumor stage was also adjusted for), survival was similar at HVHs and at LVHs (HR, 0.99; 95% confidence interval, 0.84-1.18).
Conclusions: This study revealed no effect of hospital volume on long-term survival after esophageal cancer surgery. Tumor biology apparently has a greater effect on the chances of long-term survival than hospital volume.