The relationship between case volume, care quality, and outcomes of complex cancer surgery

Background: How case volume and quality of care relate to each other and to results of complex cancer surgery is not well-understood.

Study design: Observational cohort of 14,170 patients 18 years or older who underwent pneumonectomy, esophagectomy, pancreatectomy, or pelvic surgery for cancer between October 1, 2003 and September 1, 2005 at a US hospital participating in a large benchmarking database. Case volumes were estimated within our dataset. Quality was measured by determining whether ideal patients did not receive appropriate perioperative medications (such as antibiotics to prevent surgical site infections), both as individual "missed"measures and as overall number missed. We used hierarchical models to estimate effects of volume and quality on 30-day readmission, in-hospital mortality, length of stay, and costs.

Results: After adjustment, we noted no consistent associations between higher hospital or surgeon volume and mortality, readmission, length of stay, or costs. Adherence to individual measures was not consistently associated with improvement in readmission, mortality, or other outcomes. For example, continuing antimicrobials past 24 hours was associated with longer length of stay (21.5% higher, 95% CI, 19.5-23.6%) and higher costs (17% higher, 95% CI, 16-19%). In contrast, overall adherence, although not associated with differences in mortality or readmission, was consistently associated with longer length of stay (7.4% longer with 1 missed measure and 16.4% longer with ≥2) and higher costs (5% higher with 1 missed measure, and 11% higher with ≥2).

Conclusions: Although hospital and surgeon volume were not associated with outcomes, lower overall adherence to quality measures is associated with higher costs, but not improved outcomes. This finding might provide a rationale for improving care systems by maximizing care consistency, even if outcomes are not affected.