Superior Survival Outcomes of Epithelial Ovarian Cancer Patients in the Universal Access Military Healthcare System Compared With the National Surveillance, Epidemiology, and End Results Program
Abstract
Introduction
To compare 5-year overall survival outcomes in patients diagnosed with epithelial ovarian carcinoma in the United States Department of Defense (DoD) cancer registry, who received universal healthcare, with the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute, the U.S. general population.
Materials and Methods
Eligible patients were diagnosed with invasive stage I-IV epithelial ovarian carcinoma between 1987 and 2013. Each patient from the Automated Center Tumor Registry (ACTUR) for the DoD managed by the Joint Pathology Center was matched in a 1:4 ratio with stratification for age group, race, year of diagnosis, histology, and to patients in the 18-region SEER program. Five-year overall survival was evaluated using the Kaplan-Meier method and compared using log-rank test. Adjusted hazard ratio (AHR) and 95% CI for all-cause death in ACTUR compared with SEER were estimated from multivariable Cox proportional regression modeling controlling for age, race, year of diagnosis, region of diagnosis, stage, histology, and grade.
Results
There were 1,504 and 6,016 patients from ACTUR and SEER, respectively. Epithelial ovarian cancer patients in ACTUR had better 5-year overall survival than those in SEER (53.2% vs. 47.7%, log-rank P = .0010). The AHR (95% CI) was 0.83 (0.76-0.91, P < .0001) for ACTUR versus SEER patients after adjustment for age, race, year of diagnosis, region, histology, tumor stage, and grade. Subset analysis revealed that the reduced adjusted risk of death in ACTUR versus SEER patients with epithelial ovarian cancer remained significant in the subset diagnosed either at 35-49 years old (AHR = 0.66, 95% CI = 0.52-0.83; P = .0005) or 65+ years old (AHR = 0.82, 95% CI = 0.70-0.96; P = .016), or with stage III disease (AHR = 0.79, 95% CI = 0.69-0.91, P = .002), the clear cell carcinoma subtype (AHR = 0.63, 95% CI = 0.43-0.93; P = .02) or the adenocarcinoma subtype (AHR = 0.68, 95% CI = 0.56-0.81; P < .0001). There was also exploratory evidence for a trend for decreased adjusted risk of death in the subset of patients diagnosed between 50 and 64 years old (adjusted HR = 0.88, 95% CI = 0.77-1.01), with stage IV disease (adjusted HR = 0.87, 95% CI = 0.56-1.02), or with the serous adenocarcinoma subtype (adjusted HR = 0.92, 95% CI = 0.82-1.03). Adjusted risk of death was similar for ACTUR versus SEER patients diagnosed <35 years old (adjusted HR = 1.30, 95% CI = 0.68-2.47), with stage I disease (adjusted HR = 0.76, 95% CI = 0.51-1.14), with stage II disease (adjusted HR = 0.74, 95% CI = 0.47-1.16) or with the mucinous carcinoma subtype (adjusted HR = 0.93, 95% CI = 0.60-1.43).
Conclusions
Patients with epithelial ovarian carcinoma in the DoD Cancer Registry had better 5-year overall survival compared with a matched sample of patients from the national SEER program. The reduced lethality associated with epithelial ovarian cancer overall and in a range of subsets in the universal access to care Military Health System reinforces the value of maintaining readiness, medical skills, educational programs, and superior outcomes for gynecologic cancer care within the Defense Health Agency.