Can postoperative process of care utilization or complication rates explain the volume-cost relationship for cancer surgery?

Background. Past studies identify an association between provider volume and outcomes, but less is known about the volume-cost relationship for cancer surgery. We analyze the volume-cost relationship for 6 cancer operations and explore whether it is influenced by the occurrence of complications and/or utilization of processes of care. Methods. Medicare hospital and inpatient claims for the years 2005 through 2009 were analyzed for 6 cancer resections: colectomy, rectal resection, pulmonary lobectomy, pneumonectomy, esophagectomy, and pancreatic resection. Regressions were first estimated to quantify the association of provider volume with costs, excluding measures of complications and processes of care as explanatory variables. Next, these variables were added to the regressions to test whether they weakened any previously observed volume-cost relationship. Results. Higher hospital volume is associated with lower patient costs for esophagectomy but not for other operations. Higher surgeon volume reduces costs for most procedures, but this result weakens when processes of care are added to the regressions. Processes of care that are frequently implemented in response to adverse events are associated with 14% to 34% higher costs. Utilization of these processes is more prevalent among low-volume versus high-volume surgeons. Conclusion. Processes of care implemented when complications occur explain much of the surgeon volume-cost relationship. Given that surgeon volume is readily observed, better outcomes and lower costs may be achieved by referring patients to high-volume surgeons. Increasing patient access to surgeons with lower rates of complications may be the most effective strategy for avoiding costly processes of care, controlling expenditure growth.