Volume-outcome relationships in pancreatoduodenectomy for cancer.
BACKGROUND
Volume-outcome relationships in pancreatic surgery are well established, but an optimal volume remains to be determined. Studies analyzing outcomes in volume categories exceeding 20 procedures annually are lacking.


STUDY DESIGN
A consecutive 3420 patients underwent PD for primary pancreatic or periampullary carcinoma (2005-2013) and were registered in the Netherlands Cancer Registry. Relationships between hospital volume (< 5, 5-19, 20-39 and ≥ 40 PDs/year) and mortality and survival were explored.


RESULTS
There was a non-significant decrease in 90-day mortality from 8.1 to 6.7% during the study period (p = 0.23). Ninety-day mortality was 9.7% in centers performing < 5 PDs/year (n = 185 patients), 8.9% for 5-19 PDs/year (n = 1432), 7.3% for 20-39 PDs/year (n = 240) and 4.3% for ≥ 40 PDs/year (n = 562, p = 0.004). Within volume categories, 90-day mortality did not change over time. After adjustment for confounding factors, significantly lower mortality was found in the ≥ 40 category compared to 20-39 PDs/year (OR = 1.72 (1.08-2.74)). Overall survival adjusted for confounding factors was better in the ≥ 40 category compared to categories under 20 PDs/year: HR (≥ 40 vs 5-19/year) = 1.24 (1.09-1.42). In the ≥ 40 category significantly more patients received adjuvant chemotherapy and had > 10 lymph nodes retrieved compared to lower volume categories.


CONCLUSIONS
Volume-outcome relationships in pancreatic surgery persist in centers performing ≥ 40 PDs annually, regarding both mortality and survival. The volume plateau for pancreatic surgery has yet to be determined.