Hospital volume and outcome in rectal cancer patients; results of a population-based study in the Netherlands.

BACKGROUND: Clinically staged T1-3 rectal cancer (cT1-3) is generally treated by total mesorectal excision(TME) with or without neoadjuvant therapy and sometimes requires beyond TME-surgery, whereas cT4 rectal cancer often requires both. This study evaluates the outcome of cT1-3 and cT4 rectal cancer according to hospital volume.

METHODS: Patients undergoing rectal cancer surgery between 2005 and 2013 in the Netherlands were included from the National Cancer Registry. Hospitals were divided into low(1-20), medium(21-50) and high(>50 resections/year) volume for cT1-3 and low(1-4), medium(5-9) and high(≥10 resections/year) volume for cT4 rectal cancer. Cox-proportional hazards model was used for multivariable analysis of overall survival (OS).

RESULTS: A total of 14.050 confirmed cT1-3 patients and 2.104 cT4 patients underwent surgery. In cT1-3 rectal cancer, there was no significant difference in 5-year OS related to high, medium and low hospital volume (70% vs. 69% vs. 69%). In cT4 rectal cancer, treatment in a high volume cT4 hospital was associated with a survival benefit compared to low volume cT4 hospitals (HR 0.81 95%CI 0.67-0.98) adjusted for non-treatment related confounders, but this was not significant after adjustment for neoadjuvant treatment. Patients with cT4-tumours treated in high volume hospitals had a significantly lower age, more synchronous metastases, more patients treated with neoadjuvant therapy and a higher pT-stage.

CONCLUSION: Hospital volume was not associated with survival in cT1-3 rectal cancer. In cT4 rectal cancer, treatment in high volume cT4 hospitals was associated with improved survival compared to low volume cT4 hospitals, although this association lost statistical significance after correction for neoadjuvant treatment.