Women with invasive, well-differentiated mucinous ovarian cancer are more likely to die from their disease within 10 years of diagnosis than women with mucinous borderline ovarian tumors, according to a retrospective study of more than 2,700 cases.
The analysis also revealed different clinical characteristics, reported lead author Koji Matsuo, MD, PhD of the University of Southern California, Los Angeles, and his colleagues. For example, compared with borderline ovarian tumors (BOT), patients with ovarian cancer (OC) were usually older and had undergone hysterectomy.
“Our study endorses the importance of making the proper diagnosis for invasive cancer when the ovarian tumor is of mucinous histology,” the investigators wrote in Gynecologic Oncology.
Using Surveillance, Epidemiology, and End Results data from 1988-2000, the analysis included 581 cases of stage I, invasive, well-differentiated mucinous OC and 2,130 cases of stage I mucinous BOT. The investigators noted “histological misclassification of BOT as OC or OC as BOT is not uncommon,” because of similar histopathologic characteristics.
Multivariable analysis showed that, compared with cases of BOT, women with OC were more often from the eastern United States (22.0% vs. 13.6%), older (51.9 vs. 48.0 years), and had a history of lymphadenectomy (47.0% vs. 23.2%) or hysterectomy (64.4% vs. 35.8%). Women with OC were also more likely to have tumors smaller than 4 cm (12.9% vs. 8.9%) and stage T1c disease (15.7% vs. 7.3%). Rates of OC declined over time, from 34.7% during 1988-1991 to 22.0% during 1997-2000. Following propensity score matching, multivariable analysis showed that 10-year cause-specific survival rates for OC and BOT were 92.7% and 97.5%, respectively, giving OC a hazard ratio of 2.03 (P = .007). Overall survival showed a similar disparity, of 76.1% for OC, compared with 83.6% for BOT. The investigators concluded that “survival of these two diseases is completely different.”
Regarding histopathologic misclassification, the investigators proposed “a standardized specimen sectioning protocol and diagnostic criteria for mucinous ovarian tumors.”
The study was funded by Ensign Endowment for Gynecologic Cancer Research. The investigators reported financial relationships with KIYATEC, BioPath, M-Trap, and Chugai.
SOURCE: Matsuo K et al. Gynecol Oncol. 2019 Feb 20. doi: 10.1016/j.ygyno.2019.02.003.