Abstract 4124: Ovarian cancer survival by tumor subtype

Abstract

Abstract Introduction: Epithelial ovarian cancer is heterogeneous, with subgroups defined by cell of origin (ovary vs. fallopian tube), histology, and carcinogenic pathway (the etiologic pathway through which tumors arise: type I tumors develop on the ovarian surface and are low grade serous or mucinous histology; type II tumors develop through endometriotic implantation and are clear cell or endometrioid histology; type III tumors originate in the fallopian tube and are high grade serous histology). Although differences in associations have been observed with risk of incident ovarian cancer, few studies have examined differences in survival by subtype. In the New England Case-Control Study of ovarian cancer (NECC), we examined differences in survival by tumor dominance (a surrogate for cell of origin), histology, and carcinogenic pathway. Methods: Among 2076 women with epithelial ovarian cancer (1991-2008), 892 deaths were observed. Cox proportional hazards regression was used to calculate hazards ratios (HRs) and 95% confidence intervals (95% CI) for the association of ovarian cancer subtype with overall survival, adjusting for age at diagnosis, study phase, year of diagnosis (as a proxy for treatment), BMI, and smoking status. Results: Serous invasive tumors were more likely to be non-dominant (likely fallopian origin) and type III. Compared to serous invasive tumors, all other tumor histologies had statistically significantly improved survival. Similarly, dominant tumors (i.e., likely ovarian origin) had greater survival than non-dominant tumors (HR: 0.38; 95% CI: 0.31-0.47). Type I (mucinous and low grade serous) and type II (endometrioid and clear cell) tumors had better survival than type III (high grade serous) tumors (HR: 0.21; 95%CI: 0.16-0.28 and HR: 0.23; 95% CI: 0.18-0.29, respectively). Conclusion: Regardless of how subtype was defined, high grade, invasive serous tumors had worse survival compared to other tumor subtypes. This underscores the need for prevention and treatment targeted at these aggressive tumors. Table.Associations between tumor subtype and overall survivalSubtypeDeaths/CasesMedian Survival (years)HR (95% CI)HistologySerous invasive654/9683.21.00 (ref.)Serous borderline25/25010.10.35 (0.18-0.67)Mucinous36/2427.10.38 (0.25-0.58)Endometrioid68/3314.70.28 (0.21-0.37)Clear cell29/1163.40.30 (0.21-0.44)DominanceNon-dominant268/3853.31.00 (ref.)Dominant162/6034.00.38 (0.31-0.47)PathwayType III596/8563.21.00 (ref.)Type II97/4474.00.23 (0.18-0.29)Type I60/2915.70.21 (0.16-0.28) Citation Format: Elizabeth M. Poole, Daniel W. Cramer, Allison F. Vitonis, Kathryn L. Terry. Ovarian cancer survival by tumor subtype. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4124. doi:10.1158/1538-7445.AM2014-4124