Background: To evaluate specialization in National Health Service (NHS) cancer care, volume-outcome relationships were examined.
Methods: This was a cohort study of 1512 patients with oesophageal or gastric cancer in 23 acute NHS hospitals. Outcomes were survival time and operative (30 day) mortality. Multiple regression analysis was performed, adjusted for diagnoses, prognoses and treatments.
Results: For oesophageal cancer, the operative mortality rate decreased by 40 per cent (odds ratio 0.60 (95 per cent confidence interval (c.i.) 0.36 to 0.99 per cent); P = 0.047) for each increase of ten patients in doctors' annual surgical caseloads, and the risk of death decreased by 8 per cent (hazard ratio 0.92 (95 per cent c.i. 0.85 to 0.99); P = 0.021) for each increase of ten patients in doctors' annual caseloads. For gastric cancer, the operative mortality rate decreased by 41 per cent (odds ratio 0.59 (95 per cent c.i. 0.32 to 1.07)) for each increase of ten patients in doctors' annual surgical caseloads, and the risk of death decreased by 7 per cent (hazard ratio 0.93 (95 per cent c.i. 0.89 to 0.98); P = 0.009) for each increase of ten patients in hospitals' annual caseloads. Patients of higher-volume doctors were more likely to receive most investigations and treatments, independently of presenting features.
Conclusion: The study supports concentration of services for oesophageal and gastric cancers. Specialization of doctors and their teams is at least as important as specialization of hospitals.