The National Cancer Database report on advanced-stage epithelial ovarian cancer: Impact of hospital surgical case volume on overall survival and surgical treatment paradigm

Abstract

Objective

To examine the effect of hospital procedure volume and other prognostic variables on overall survival outcome and likelihood of receiving standard recommended care among patients with advanced-stage epithelial ovarian cancer.

Methods

The National Cancer Data Base (NCDB) was searched for patients undergoing primary treatment for FIGO Stage IIIC/IV epithelial ovarian cancer from 1996 to 2005. The average annual surgical procedure volume was derived for each reporting hospital. Quartile ranking discriminated four groups of hospitals based on annual surgical volume: low (< 9), intermediate (9–20), high (21–35), and very high (> 35). Cox proportional hazards modeling was used to determine the impact on overall survival of hospital surgical volume adjusted for treatment, FIGO/AJCC stage, ethnicity, age, payer status, household income, and tumor grade. Binomial multivariate logistic regression modeling was used to assess differences in patient demographic, tumor, and treatment variables between high/very high volume hospitals and low/intermediate volume hospitals.

Results

A total of 45,929 patients were identified. After adjusting for other factors, overall survival was significantly correlated with hospital case volume: very high (reference); high (HR 0.98, 95% CI = 0.92–1.04); intermediate (HR 1.08, 95% CI = 1.01–1.15); and low (HR 1.14, 95% CI = 1.07–1.22). Compared to low and intermediate volume hospitals, patients treated at very high and high-volume hospitals were less likely to receive neo-adjuvant chemotherapy (OR = 0.33, 95% CI = 1.18–1.50) or surgery alone (OR = 0.77, 95% CI = 0.73–0.82) instead of initial surgery and adjuvant chemotherapy.

Conclusions

Hospital ovarian cancer surgical volume ≥ 21 cases/year is associated with a higher likelihood of patients with Stage IIIC/IV epithelial ovarian cancer receiving standard treatment (surgery followed by adjuvant chemotherapy). Even after adjusting for treatment paradigm and other factors, hospital volume ≥ 21 cases/year was significantly predictive of improved overall survival outcome.

Introduction

The American Cancer Society estimated that 21,550 women in the United States will be diagnosed with ovarian cancer in 2009, and 14,600 women will die of this disease [1]. While advances in novel chemotherapeutic agents and treatment strategies continue to show incremental benefits in survival, recent attention has focused on the potential for improved healthcare outcomes through concentration of cancer services. For example, Hillner et al. [2] reported findings of a comprehensive review of the health services literature and found that across all studies, the absolute benefit from care at high-volume centers exceeded the benefit from breakthrough treatments and concluded that efforts to concentrate the initial care for all forms of cancer should be undertaken. A number of population-based studies have demonstrated that the surgical expertise and multidisciplinary care provided to patients with ovarian cancer by high-volume surgeons and high-volume centers is superior when compared to low-volume providers [3], [4], [5], [6], [7], [8], [9], [10], [11], [12]. However, other investigators have reported contradictory findings [13], [14], [15]. With recent attention focused on improving the quality of cancer care, correlative clinical outcome data for healthcare delivery system characteristics can play an important role in quality improvement efforts. Therefore, the potential relationship between hospital ovarian cancer case volume and meaningful clinical outcomes must be clearly defined.

The National Cancer Data Base (NCDB) is a joint program of the American College of Surgeons Commission on Cancer and the American Cancer Society and serves to collect data for research and quality improvement. Established in 1985, the NCDB contains data from approximately 20 million patients from more than 1430 participating hospitals, and captures nearly 80% of newly diagnosed cancers in the United States each year. The NCDB collects patient demographics, tumor characteristics, clinical and pathologic TNM stage classification, treatments administered, and survival data [16], [17], [18], [19], [20]. The objective of this study was to examine and attempt to quantify the effect of hospital procedure volume on overall survival and processes of care for women with advanced-stage invasive epithelial ovarian cancer within the context of demographic and disease-related prognostic factors using the NCDB.