Differences in therapy and survival between lung cancer patients treated in hospitals with high and low patient case volume.
BACKGROUND
In light of political discussions about minimum case volumes and certified lung cancer centers, this observational study investigates differences in therapy and survival between high vs. low patient volume hospitals (HPVH vs. LPVH).


METHODS
We identified 12,374 lung cancer patients treated in HPVH (>67 patients) and LPVH in 2013 from German health insurance claims. Stratified by metastasis status (no metastases, nodal metastases, systemic metastases), we compared HPVHs and LPVHs regarding likelihood of resection and systemic therapy, type of systemic therapy, and surgical outcomes, using multivariate logistic models. Three-year survival was modeled using Cox regression. We adjusted all regression models for age, gender, comorbidity, and residence area, and included a cluster variable for the hospital.


RESULTS
Around 24 % of patients were treated in HPVHs. Irrespective of stratum and subgroup, three-year survival was significantly better in HPVHs. In patients with systemic metastases (OR = 1.84, CI=[1.22,2.76]) and without metastases (OR = 3.28, CI=[2.13, 5.04]), resection was more likely in HPVHs. Among patients with systemic therapy, the odds of receiving pemetrexed was higher in HPVHs, in patients with nodal metastases (OR = 1.57, CI=[1.01,2.45]). In resected patients without metastases the odds ratio of receiving a thoracoscopic lobectomy was 2.28 (CI=[1.04,4.99]) in HPVHs.


CONCLUSION
Our data suggests that case volume is clinically relevant in resected and non-resected lung cancer patients, but optimal minimum case volumes may differ for subgroups.