Abstract 150: Ovarian visualization in transvaginal ultrasound scans and risk of ovarian cancer.
Authors: Bodelon Clara , Black Amanda , Pfeiffer Ruth M. , Sherman Mark E. 
Published: August 2014

Background. Ovarian cancer is typically diagnosed at an advanced stage, resulting in poor survival. Detection of ovarian cancer at an early curable stage could reduce mortality; however, annual screening with transvaginal ultrasound (TVU) and CA-125 serum levels using predetermined cutpoints did not lower mortality in the Prostate, Lung, Colorectal and Ovarian (PLCO) trial. In this trial, approximately 40% of TVU scans resulted in non-visualization of the ovaries. Currently, TVU studies consider non-visualization of the ovaries as having normal ovaries, even though this may confer risk information. Accordingly, we assessed risk of ovarian cancer among women with non-visualization of the ovaries by TVU in the PLCO trial.

Methods. Study participants were women from the ovarian screening arm of the PLCO trial. Briefly, women aged 55-74 years were recruited at ten US clinical centers between 1993 and 2001. Those with a previous diagnosis of ovarian cancer were excluded from enrollment. Subjects with at least one ovary underwent a TVU at baseline and annually for 3 additional years and were followed-up for up to 13 years. Individuals were excluded from the current analysis if they did not complete the baseline questionnaire or did not have at least one adequate screening (i.e., visualization of the iliac vessels). Ovaries were considered not visualized if they were not seen after a search of at least 5 minutes. Associations between participant characteristics and ovarian visualization were estimated using logistic regression models adjusted for age and calendar year. Hazard ratios (HR) and 95% confidence intervals (CI) were computed to estimate the risk of ovarian cancer with TVU visualization using Cox proportional hazard models. Age was the time metric and models were adjusted for calendar year, body mass index (BMI), race, parity and oral contraceptive (OC) use.

Results. Our analysis included 29,329 women, with 98.6% of them having two or more TVUs. Two hundred and five women were diagnosed with invasive ovarian cancer during follow-up. Lack of visualization of the ovaries by TVU was associated with older age, non-White race, greater BMI, ever use of OC and ever having children. However, ovarian visualization was not associated with risk of ovarian cancer (HR=1.17; 95% CI: 0.86-1.59). Moreover, women with visualized ovaries but negative TVUs were not at elevated ovarian cancer risk compared to women with non-visualized ovaries (HR=1.06; 95% CI: 0.77-1.45).

Conclusions. Women with non-visualization of the ovaries by TVU and those with visualization and a negative result do not have a different risk of ovarian cancer, suggesting that data for these women may be combined. Ongoing analysis will examine serial measurements of ovarian volume by TVU and ovarian cancer risk.

Citation Format: Clara Bodelon, Amanda Black, Ruth M. Pfeiffer, Mark E. Sherman. Ovarian visualization in transvaginal ultrasound scans and risk of ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 150. doi:10.1158/1538-7445.AM2013-150