The influence of facility volume on patient treatments and survival outcomes in nasopharyngeal carcinoma

Abstract

Background: This study evaluates the influence of facility case-volume on nasopharyngeal carcinoma (NPC) treatments and overall survival (OS).

Methods: The 2004-2015 National Cancer Database was queried for patients with NPC receiving definitive treatment.

Results: A total of 8260 patients (5-year OS: 63.4%) were included. The 1114 unique facilities were categorized into 854 low-volume (treating 1-8 patients), 200 intermediate-volume (treating 9-23 patients), and 60 high-volume (treating 24-187 patients) facilities. Kaplan-Meier log-rank analysis demonstrated significantly improved OS with high-volume facilities (p < 0.001). On cox proportional-hazard multivariate regression after adjusting for age, sex, income, insurance, comorbidity index, histology, AJCC clinical stage, and treatment type, high-volume facilities were associated with lower mortality risk than low-volume (HR = 0.865, p = 0.019) and intermediate-volume facilities (HR = 0.916, p = 0.004). Propensity score matching analysis confirmed this association (p < 0.001).

Conclusion: Higher facility volume was an independent predictor of improved OS in NPC, suggesting a possible survival benefit of referrals to high-volume medical centers.

Keywords: facility volume; hospital volume; nasopharyngeal carcinoma; outcomes; overall survival.

Figure 1.

Flowchart of patient selection process.

Figure 2.

Kaplan-Meier curves of overall survival in patients with nasopharyngeal carcinoma stratified by low-volume (1-8 patients treated per center, total n=2,909 patients), intermediate-volume (9-23 patients treated per center, total n=2,647 patients), and high-volume facility (24-187 patients treated per center, total n=2,704 patients) patients. The analysis demonstrated a statistically significant positive association between facility volume and OS (p<0.001). Shaded areas indicate 95% confidence intervals.

Figure 3.

Kaplan-Meier (KM) curves of overall survival (OS) in patients with nasopharyngeal carcinoma (NPC) matched by their demographic and clinical factors, demonstrating significant improvement of OS with high facility volume. Figure (A) compares matched patients treated at low (n=1,550) and intermediate (n=1,550) volume facilities. Figure (B) compares matched patients treated at intermediate (n=1,550) and high (n=1,550) volume facilities. Figure (C) compares matched patients treated at low (n=1,601) and high (n=1,601) volume facilities. Shaded areas indicate 95% confidence intervals.