The Influence of Hospital Volume on the Outcomes of Nasopharyngeal, Sinonasal and Skull-base Tumors: A Systematic Review of the Literature

Background: Health care researchers are pursuing strategies focusing on providing quality care for the lowest possible cost. The center of excellence model hypothesizes that increased volume in a specialized center will lead to better and more affordable care. A focus in outcome research studies, including those in skull base, is volume-outcome associations. In this systematic review, we sought to characterize the volume-outcome data for primary surgically treated sinonasal and skull base (anterior and lateral) tumors and (chemo) radiation treated nasopharyngeal malignancy.

Methods: PubMed was searched for relevant National Database and Multi-institutional studies published between 1990 and 2019. Key words included “hospital volume,” “surgeon volume,” “surgeon experience,” and outcomes for “nasopharyngeal carcinoma,” “sinonasal carcinomas,” “pituitary tumors,” “acoustic neuromas,” “chordomas,” and “skull base tumors.” Single-institution studies and self-reported surveys were excluded.

Results: A total of 18 studies addressed volume-outcome associations. These studies focused on the impact of volume on either survival or treatment related complications depending on whether the pathology was benign or malignant. Two studies were excluded for being either single-institution or survey-based. Five studies utilized the National Cancer Database (NCDB), four used the National Inpatient Sample (NIS), and one used the U.S. Surveillance, Epidemiology, and End Results (SEER) database. All others used either state-specific databases or large multi-institution retrospective databases. With malignant pathology, interest was focused on survival outcomes. Five studies showed improved survival with treatment in high volume centers and two showed no association with survival. One showed an increased risk of complications. For those treated with definitive radiation for nasopharyngeal carcinoma (NPC), three studies identified a statistically significant positive association between hospital volume and overall survival (OS). In studies of patients treated surgically for sinonasal malignancy, two studies demonstrated no relationship between volume and survival and one study noted improvement between middle-tertile volume centers and low-tertile centers only. One study of the NIS found an increased risk of complications at high-volume centers. In one study of the SEER database, greater hospital volume was associated with improved survival for patients with skull base chordomas. For benign pathologies, interest was focused on perioperative complications. One study showed reduced risk of perioperative mortality in high-volume centers and three showed no association. Seven showed a reduced risk of complications and one showed no association. On assessment of three pituitary adenoma surgery NIS studies, one showed a correlation between high-volume centers and lower perioperative morbidity and mortality, and two demonstrated equal morbidity and mortality. Four studies of volume outcomes for acoustic neuroma demonstrated reduced perioperative morbidity in high-volume centers, while one found no association with complications.

Conclusion: Systematic review of the literature does not demonstrate consistent findings among the subsites assessed. Survival outcomes following primary radiation treatment for NPC do appear related to hospital volume but surgically treated sinonasal cancer does not. Most of the literature, evaluating surgery for benign conditions of the skull base demonstrates lower perioperative morbidity in high-volume centers. This suggests that further studies must be conducted to understand the effect of treatment centralization on outcomes.