Provider volume and outcomes for oncological procedures.

Background: Oncological procedures may have better outcomes if performed by high-volume providers.
Methods: A review of the English language literature incorporating searches of the Medline, Embase and Cochrane collaboration databases was performed. Studies were included if they involved a patient cohort from 1984 onwards, were community or population based, and assessed health outcome as a dependent variable and volume as an independent variable. The studies were also scored quantifiably to assess generalizability with respect to any observed volume-outcome relationship and analysed according to organ system; numbers needed to treat were estimated where possible.
Results: Sixty-eight relevant studies were identified and a total of 41 were included, of which 13 were based on clinical data. All showed either an inverse relationship, of variable magnitude, between provider volume and mortality, or no volume-outcome effect. All but two clinical reports revealed a statistically significant positive relationship between volume and outcome; none demonstrated the opposite.
Conclusion: High-volume providers have a significantly better outcome for complex cancer surgery, specifically for pancreatectomy, oesphagectomy, gastrectomy and rectal resection.