Ovarian Cancer Outcomes May Be Improved by Prior Oral Contraceptive Use

Oral Contraceptives

Oral Contraceptives

Ovarian cancer outcomes appear to be improved in women with a history of oral contraceptive use, according to a retrospective study¹recently published in BMC Cancer. Women in the study who reported using oral contraceptives had improved progression-free survival (PFS) compared with those who reported never using them.

Numerous previous studies have shown oral contraceptive use to be associated with a reduced risk of ovarian cancer, but few have explored the connection between oral contraceptives and outcomes in patients who ultimately develop ovarian cancer, noted Aminah Jatoi, MD, an oncologist with the Mayo Clinic in Rochester, MN, and co-lead author of the study, in a Mayo Clinic press release.²

The study, by Jatoi et al, included 1398 women aged 20 years or older, who had been treated at the Mayo Clinic between 2000 and 2013 for invasive primary epithelial ovarian cancer, fallopian tube cancer, or peritoneal cancer. These ovarian malignancies were chosen because they behave similarly and have comparable treatments.

All study participants completed a questionnaire about their risk factors that included queries about their oral contraceptive use, menstrual history, number of live births, and other hormone-related factors. Electronic medical records were used to extract additional details, including information on patients’ tumor histology, type of surgery and medical treatments used, smoking history, and family history of breast or ovarian cancer.

On the questionnaires, 827 women reported previous oral contraceptive use and 571 women reported no OC use. The median duration of oral contraceptive use was 60 months (1-444). Younger women were more likely to report previous oral contraceptive use.

The investigators used multivariate and univariate analyses to assess the effect of oral contraceptives on PFS and overall survival (OS). The multivariate analyses showed significantly longer PFS for oral contraceptive users compared with never-users (HR, 0.78; 95% CI, 0.64-0.96; P = .02). Univariate analyses also suggested a significant advantage in PFS for oral contraceptive users compared with never-users (HR, 0.71; 95% CI, 0.61-0.83; P <.0001). No OS benefit was observed in multivariate analyses. Although univariate analyses showed an OS benefit (HR, 0.73; 95% CI, 0.62-0.86; P = .0002), the finding lost statistical significance once the researchers adjusted for the women&rsquo;s age at diagnosis.

Jatoi et al acknowledged at least three limitations with their study: (1) the questionnaire did not capture data about the type of oral contraceptive used (they noted this information could be informative because certain types of contraceptives appear to be more protective, such as those with high progesterone content); (2) the study did not analyze cause-specific mortality, making it unclear how many deaths were attributed to causes other than ovarian cancer; and (3) it was unclear how recently oral contraceptives had been used by patients, which could have an important impact on the strength of the associations made in the study.

&ldquo;Despite such limitations, our study—coupled with several that preceded it&mdash;points to a need to investigate mechanisms that explain how and why prior oral contraceptive use appears to improve clinical outcomes in ovarian cancer patients,&rdquo; Jatori et al wrote in their article.¹In a video discussing the study, Jatoi urges other centers to confirm her group's findings, noting, &ldquo;They will become more robust if other centers look at this issue as well and find the same thing in their groups of patients.&rdquo;²She also suggests her study&rsquo;s finding may have therapeutic potential by helping identify ways to intervene once patients develop ovarian cancer.

References

1. Jatoi A, Foster NR, Kalli KR, et al. Prior oral contraceptive use in ovarian cancer patients: assessing associations with overall and progression-free survival. BMC Cancer. 2015;15:711. doi:10.1186/s12885-015-1774-z.

2. Prior oral contraceptive use associated with better outcome for ovarian cancer patients [press release]. Rochester, MN: Mayo Clinic; November 11, 2015. http://newsnetwork.mayoclinic.org/discussion/previous-oral-contraceptive-use-associated-with-better-outcomes-in-patients-with-ovarian-cancer-mayo-study-finds. Accessed December 8, 2015.