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Cervical Cancer Screening May Be Less Effective in Obese Women

Posted on January 23, 2018

In a population of 1,000,000 women undergoing state-of-the-art cervical cancer screening, researchers at the National Cancer Institute (NCI) found that overweight and obese women had an increased risk of cervical cancer compared to normal weight women, likely due to less effective cervical cancer screening. The findings were published January 22, 2018, in the Journal of Clinical Oncology.

Some previous studies have linked obesity with increased cervical cancer incidence and mortality, though the reasons have not been well-understood. This paper reports on screening data from 1,000,000 women undergoing routine cytology (i.e., Pap) and human papillomavirus (HPV) DNA testing (“co-testing”) in the Kaiser Permanente Northern California (KPNC) health care system.

The goal of screening is to identify and treat cervical precancers before cervical cancer develops. Precancers are typically diagnosed through detection of persistent HPV infection and/or abnormal cytology results. Initially, a KPNC technologist noticed that cervical cancers were being diagnosed more often in obese women, and that cancers in obese women were more likely to be HPV negative. In following up on this observation, Dr. Megan Clarke and colleagues confirmed that increasing body mass index (BMI) was associated with a lower rate of detection of cervical precancer, and a corresponding higher risk of cervical cancer diagnosis, irrespective of age, race/ethnicity, HPV status, and histology.

Evidence from this study suggests that reduced sensitivity of both HPV and cytology testing, in addition to inadequate cervical visualization if a biopsy is indicated, may be contributing to reduced efficacy of cervical cancer screening in overweight and obese women. Improvements in equipment and/or procedures to assure adequate sampling and visualization of women with elevated body mass might reduce cervical cancer incidence.

Reference: Clarke MA....Schiffman M, et al. Epidemiologic evidence that excess body weight increases risk of cervical cancer by decreased detection of precancer. J Clin Oncol, January 22, 2018. DOI: 10.1200/JCO.2017.75.3442.