Hospital Volume for Rectal Cancer Resection Plays a Pivotal Role in Improving Outcomes: A Population-based Analysis.

Objective: Assessing the association between hospital surgical volume (SV) and outcomes after rectal cancer surgery (RCS), using national population-based data.

Summary Background Data: For RCS, the association of higher SV with improved short- and/or long-term outcomes remains controversial.

Methods: National cancer registry data and administrative data were used to select patients diagnosed with stage I-III rectal cancer in 2009-2018 and who underwent RCS. The average annual SV of RCS was categorised as low (<15; LV), medium (15-29; MV) or high (≥30; HV). The association between SV and 90-day and 1-year excess postoperative mortality (90DPM and 1YEPM) and 5-year observed survival (5YOS) was evaluated.

Results: From the 11,519 patients , RCS was performed in LV (4,088; 36%), MV (2,795; 24%) or HV (4,636; 40%) hospitals. Observed 90DPM was significantly better in HV (2.3% 95%CI[1.9,2.8]) than in LV (3.7% 95%CI[3.2,4.4]) and MV (3.5% 95%CI[2.9,4.3]) with adjusted OR 1.4, P<0.0001. Continuous regression analysis showed significantly higher 90DPM in annual SV <35 compared to ≥35 (OR 1.6 95%CI[1.21,2.11]; P=0.0009). Observed 1YEPM was significantly better in HV (2.9% 95%CI[2.2,3.6]) compared to LV (4.7% 95%CI [3.9,5.6]) with adjusted excess HR 1.31 95%CI[1.00,1.73] and P=0.05, and to MV (5.0% 95%CI[4.0,6.1]) with adjusted excess HR 1.45 95%CI[1.09,1.94] and P=0.01. The 5YOS was significantly better in HV (75.9% 95%CI[74.6,77.2]) than in LV (70.3% 95%CI[68.8,71.8]) and MV (71.5% 95%CI[69.7,73.2]) with adjusted HR 1.4 in both LV and MV versus HV, P≤0.003.

Conclusions: This population-based study identified robustly superior outcomes at 90-days, 1-year and 5-years after RCS in hospitals with higher volumes.