Impact of hospital volume and margin status on survival following radical hysterectomy: An expanded NCDB study.

Abstract

e17527 Background: Use of a minimally invasive surgical (MIS) approach to manage early-stage cervical cancer has been previously associated with an elevated risk of disease recurrence and death. However, the reasons why MIS would lead to worse clinical outcomes remains unclear. Here, we sought to determine whether hospital surgical volume and surgical margin status contribute to worse outcomes previously reported for minimally invasive radical hysterectomy (RH-MIS). Methods: Demographic and outcome data for women diagnosed with an invasive carcinoma of the cervix (SCCa) between 2010 and 2015 were abstracted from the National Cancer Database (NCDB). Differences by surgery type were examined using chi-square test for categorical variables and independent samples t-test test for continuous variables. Surgical margin status was reported as either positive or negative according to the presence of malignancy. Overall survival was evaluated using the Kaplan-Meier method and multivariable Cox proportional hazards regression. Analyses were stratified by hospital volume. Low volume facilities were defined as institutions performing <10 surgeries per year. Results: We identified a total of 5,090 women who underwent radical hysterectomy by either minimally invasive (n=2181) or open (n=2909) approach. Between 2010 and 2015, the proportion of radical hysterectomies performed by RH-MIS increased from 42.7% to 70.3% of all cases. In contrast to prior reports, 5-year survival among RH-MIS patients was significantly better compared to RH-open patients (92.5% vs. 90.8%, p=0.02). However, women who underwent RH-MIS were significant younger (45.6±12.3 v. 46.8±12.3 years, p<0.001), more educated (p<0.001), more likely to be White Non-Hispanic (p<0.001) and diagnosed with earlier stage disease (p<0.008). Women who underwent RH-MIS were also less likely to have positive surgical margins (2.2% v 3.5%, p=0.006). After accounting for these differences, there was no statistically significant difference in survival for women undergoing RH-MIS vs. RH-open (HR, 1.18; 95% CI: (0.96-1.45). Positive margin status was associated with worse survival only at low-volume hospitals (HR, 2.30; 95% CI: 1.09-11.31). However, no other association between hospital volume, surgical route, margin status and survival was observed. Curiously, survival for women diagnosed in 2012 (HR, 1.51; 95% CI, 1.05 – 2.17) and 2013 (HR, 1.49; 95% CI, 1.03-2.15) not other years was significantly worse when compared to 2015, regardless of surgical route. Conclusions: Positive surgical margins following radical hysterectomy appear to be most effectively addressed at high volume centers caring for women with cervical cancer. These observations underscore a national need for equitable access to radiation care for women being treated for early stage cervical cancer.