Secondary validation of an ovarian cancer-specific comorbidity index in a US population.

OBJECTIVES: The Ovarian Cancer Comorbidity Index (OCCI) is an age-specific index developed and previously found to be more predictive of overall and cancer-specific survival than the Charlson Comorbidity Index (CCI). The objective was to perform secondary validation of the OCCI in a US population. METHODS: A cohort of ovarian cancer patients undergoing primary or interval cytoreductive surgery from January 2005 to January 2012 was identified in SEER-Medicare. OCCI scores were calculated with the regression coefficients determined from the original developmental cohort for five comorbidities. Cox regression analyses were used to calculate associations between the OCCI risk groups and 5-year overall survival and 5-year cancer-specific survival in comparison to the CCI. RESULTS: A total of 5052 patients were included. Median age was 74 (range 66-82) years. 47% (n=2375) had stage III and 24% (n=1197) had stage IV disease at diagnosis. 67% had a serous histology subtype (n=3403). All patients were categorized as moderate (48.4%) or high risk (51.6%). The prevalence of the five predictive comorbidities were: coronary artery disease 3.7%, hypertension 67.5%, chronic obstructive pulmonary disease 16.7%, diabetes 21.8%, and dementia 1.2%. Controlling for histology, grade, and age-stratification, worse overall survival was associated with both a higher OCCI (hazard ratio (HR) 1.57; 95% confidence interval (CI) 1.46 to 1.69) and CCI (HR 1.96; 95% CI 1.66 to 2.32). Cancer-specific survival was associated with the OCCI (HR 1.33; 95% CI 1.22 to 1.44) but was not associated with the CCI (HR 1.15; 95% CI 0.93 to 1.43). CONCLUSIONS: This internationally developed comorbidity score for ovarian cancer patients is predictive for both overall and cancer-specific survival in a US population. CCI was not predictive for cancer-specific survival. This score may have research applications when utilizing large administrative datasets.

Exploring international differences in ovarian cancer treatment: a comparison of clinical practice guidelines and patterns of care.

INTRODUCTION: The International Cancer Benchmarking Partnership demonstrated international differences in ovarian cancer survival, particularly for women aged 65-74 with advanced disease. These findings suggest differences in treatment could be contributing to survival disparities. OBJECTIVE: To compare clinical practice guidelines and patterns of care across seven high-income countries. METHODS: A comparison of guidelines was performed and validated by a clinical working group. To explore clinical practice, a patterns of care survey was developed. A questionnaire regarding management and potential health system-related barriers to providing treatment was emailed to gynecological specialists. Guideline and survey results were crudely compared with 3-year survival by 'distant' stage using Spearman's rho. RESULTS: Twenty-seven guidelines were compared, and 119 clinicians completed the survey. Guideline-related measures varied between countries but did not correlate with survival internationally. Guidelines were consistent for surgical recommendations of either primary debulking surgery or neoadjuvant chemotherapy followed by interval debulking surgery with the aim of complete cytoreduction. Reported patterns of surgical care varied internationally, including for rates of primary versus interval debulking, extensive/'ultra-radical' surgery, and perceived barriers to optimal cytoreduction. Comparison showed that willingness to undertake extensive surgery correlated with survival across countries (rs=0.94, p=0.017). For systemic/radiation therapies, guideline differences were more pronounced, particularly for bevacizumab and PARP (poly (ADP-ribose) polymerase) inhibitors. Reported health system-related barriers also varied internationally and included a lack of adequate hospital staffing and treatment monitoring via local and national audits. DISCUSSION: Findings suggest international variations in ovarian cancer treatment. Characteristics relating to countries with higher stage-specific survival included higher reported rates of primary surgery; willingness to undertake extensive/ultra-radical procedures; greater access to high-cost drugs; and auditing.