Abstract PR11: Pre-diagnosis adiposity, physical activity, and ovarian cancer survival.
Authors: Toriola Adetunji T. , Keogan Kathleen , Morrison Leavitt , Pollack Lisa , Gerhlert Sara , Park Yikyung , Brinton Louise 
Published: May 2016

Background: The association of obesity with ovarian cancer survival is controversial, as most studies have reported null associations. A limitation, however, is that the majority of previous studies used retrospectively collected weight data among women who had already developed ovarian cancer, hence recall bias cannot be ruled out. To the best of our knowledge, only one study, conducted within the Women's Health Initiative (WHI), used prospectively collected weight data. The study reported no association between pre-diagnosis obesity and ovarian cancer survival. Further, there is a dearth of data on the association of pre-diagnosis physical activity with ovarian cancer survival. In this study, we evaluated the associations of pre-diagnosis obesity and physical activity with ovarian cancer survival among women enrolled in a larger prospective study in the U.S.

Methods: The NIH-AARP Diet and Health study includes 340,148 men and 227,021 women aged 50-71 years, who completed mailed questionnaires at baseline in 1995-1996. We identified 741 incident cases of ovarian cancer diagnosed after study enrollment. Follow-up for survival started from the date of ovarian cancer diagnosis to death or last known date alive (December 31, 2011). Mortality was ascertained by linkage with the National Death Index Plus. Pre-diagnosis body mass index ((BMI) was computed from self-reported height and weight (kg/m2). We categorized BMI into four groups: &lt;25 (reference), 25-29.99, 30-34.99, and ≥35 kg/m2. Baseline physical activity was categorized as never/rarely (reference), 1-3 times/month, 1-2 times/week, 3-4 times/week, and ≥ 5 times/week. A subset of study participants were sent an additional questionnaire where various levels of physical activity was assessed weekly as never/rarely, &lt;1 hr, 1-3 hrs, 4-7 hrs, and &gt;7 hrs. We used Cox proportional hazards model (adjusted for age at enrollment, time from entry to cancer diagnosis, hysterectomy status, cancer stage, alcohol intake to calculate the hazard ratios (HRs) and 95% confidence intervals (CI) of survival by categories of BMI and physical activity.

Results: Five hundred and forty-nine (549) deaths occurred during an average follow-up of 3 years (range 0-14.2). The mean age at enrollment was 63 years, while the mean BMI was 26.7kg/m2. More than half of the women (56.9%) were overweight at baseline. In multivariable adjusted model, pre-diagnosis obesity was associated with reduced overall survival. The HRs were 1.18 (95%CI 0.96-1.45), 1.05 (95%CI 0.82-1.36), and 1.59 (95%CI 1.16-2.18, p-trend = 0.02), respectively comparing women with BMI 25-29.99, 30-34.99, and ≥35 to those with BMI &lt;25 kg/m2. The results were similar when women diagnosed within the first 2 years of study enrollment were excluded; HR=1.72 (95%CI 1.21-2.42, p-trend ≤0.01) comparing women with BMI ≥35 kg/m2 to those with BMI &lt;25 kg/m2. Pre-diagnosis physical activity did not show similar relations with survival. The HR comparing women who engaged in vigorous physical activity &gt;5 times/week was 0.98 (95%CI 0.75-1.28) compared to those who rarely/never engaged in vigorous physical activity. Although women who engaged in 4-7 hours/week of moderate/vigorous physical activity had better survival (HR=0.67, 95%CI=0.48-0.94), no such association was seen for those engaging in similar activities for &gt;7 hours/week (HR=0.92, 95%CI=0.65-1.31, p-trend=0.16). Light physical activity was not associated with ovarian cancer survival.

Conclusion: In this prospective study, obesity prior to ovarian cancer diagnosis was associated with reduced survival. Our findings provide important new insights regarding the effects of obesity on ovarian cancer survival, and underscore the importance of maintaining a healthy weight.

This abstract is also presented as Poster B38.

Citation Format: Adetunji T. Toriola, Kathleen Keogan, Leavitt Morrison, Lisa Pollack, Sara Gerhlert, Yikyung Park, Louise Brinton. Pre-diagnosis adiposity, physical activity, and ovarian cancer survival. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr PR11.