Disparities in cancer incidence by sexual orientation.

in Cancer by Aimee K Huang, Tabor Hoatson, Payal Chakraborty, Sarah McKetta, Kodiak R S Soled, Colleen A Reynolds, Ulrike Boehmer, Alexis R Miranda, Carl G Streed, Shail Maingi, Sebastien Haneuse, Jessica G Young, Jae H Kang, S Bryn Austin, A Heather Eliassen, Brittany M Charlton

TLDR

  • This study looked at data from a group of nurses over many years to see if there were any differences in cancer rates between different groups of women based on their sexual orientation. They found that lesbian women had a higher risk of certain types of cancer than women who identified as straight. The study suggests that more research is needed to understand why this is happening and to find ways to reduce the risk of cancer for lesbian women.

Abstract

Cancer risk factors are more common among sexual minority populations (e.g., lesbian, bisexual) than their heterosexual peers, yet little is known about cancer incidence across sexual orientation groups. The 1989-2017 data from the Nurses' Health Study II, a longitudinal cohort of female nurses across the United States, were analyzed (N = 101,543). Sexual orientation-related cancer disparities were quantified by comparing any cancer incidence among four sexual minority groups based on self-disclosure-(1) heterosexual with past same-sex attractions/partners/identity; (2) mostly heterosexual; (3) bisexual; and (4) lesbian women-to completely heterosexual women using age-adjusted incidence rate ratios (aIRR) calculated by the Mantel-Haenszel method. Additionally, subanalyses at 21 cancer disease sites (e.g., breast, colon/rectum) were conducted. For all-cancer analyses, there were no statistically significant differences in cancer incidence at the 5% type I error cutoff among sexual minority groups when compared to completely heterosexual women; the aIRR was 1.17 (95% CI,0.99-1.38) among lesbian women and 0.80 (0.58-1.10) among bisexual women. For the site-specific analyses, incidences at multiple sites were significantly higher among lesbian women compared to completely heterosexual women: thyroid cancer (aIRR, 1.87 [1.03-3.41]), basal cell carcinoma (aIRR, 1.85 [1.09-3.14]), and non-Hodgkin lymphoma (aIRR, 2.13 [1.10-4.12]). Lesbian women may be disproportionately burdened by cancer relative to their heterosexual peers. Sexual minority populations must be explicitly included in cancer prevention efforts. Comprehensive and standardized sexual orientation data must be systematically collected so nuanced sexual orientation-related cancer disparities can be accurately assessed for both common and rare cancers.

Overview

  • The study analyzed 1989-2017 data from the Nurses' Health Study II, a longitudinal cohort of female nurses across the United States, to quantify sexual orientation-related cancer disparities among four sexual minority groups based on self-disclosure. The study compared any cancer incidence among these groups to completely heterosexual women using age-adjusted incidence rate ratios (aIRR) calculated by the Mantel-Haenszel method. The primary objective of the study was to assess cancer incidence across sexual orientation groups and identify any disparities in cancer risk factors among sexual minorities compared to heterosexual women.

Comparative Analysis & Findings

  • The study found no statistically significant differences in cancer incidence at the 5% type I error cutoff among sexual minority groups when compared to completely heterosexual women. However, for site-specific analyses, incidences at multiple sites were significantly higher among lesbian women compared to completely heterosexual women, including thyroid cancer, basal cell carcinoma, and non-Hodgkin lymphoma. The study suggests that lesbian women may be disproportionately burdened by cancer relative to their heterosexual peers.

Implications and Future Directions

  • The study highlights the importance of including sexual minority populations in cancer prevention efforts and the need for comprehensive and standardized sexual orientation data to accurately assess nuanced sexual orientation-related cancer disparities for both common and rare cancers. Future research should focus on identifying the underlying mechanisms of these disparities and developing targeted interventions to reduce cancer risk among sexual minorities.
Read Full Article