Disparities in Cervical and Breast Cancer Screening Among Sexual Minority Women in Japan: A Comparative Cross-Sectional Study

<b>Objectives</b>: While health disparities affecting sexual minority women are well-documented globally, little is known about cancer screening behaviors among sexual minority women in Japan. Following our previous study on breast cancer screening, this study examined cervical cancer screening participation patterns and compared screening behaviors between both cancer types among sexual minority women in Japan. <b>Methods</b>: We analyzed data from 13,730 individuals with female sex assigned at birth who participated in a nationwide online survey between September and November 2023. Multinomial logistic regression was used to examine factors associated with screening participation, comparing sexual minority women (n = 2685) and women who are not part of a sexual minority (n = 11,045). Among participants aged 40 and above (n = 8933), we compared participation patterns between cervical and breast cancer screenings. <b>Results</b>: Sexual minority women showed significantly lower cervical cancer screening rates compared to women who are not part of a sexual minority (38.7% vs. 45.6%, <i>p</i> < 0.001), with a wider disparity than observed in breast cancer screening (43.4% vs. 45.9%, <i>p</i> < 0.001). Among those aged 40 and above, sexual minority women were more likely to skip both screenings (35.0% vs. 27.2%) and less likely to participate in both (55.0% vs. 62.6%). Additionally, our analysis revealed that participants with a current mental disorder (i.e., those reporting ongoing mental health issues) were more likely to intend to undergo cervical cancer screening (aOR = 1.39, 95% CI = 1.15-1.67, <i>p</i> = 0.001). In contrast, among bisexual participants and those classified as having "other" mental health conditions-defined as a history of mental health issues without current symptoms-exhibited significantly lower odds of being screened (aOR = 0.31, 95% CI = 0.11-0.82, <i>p</i> = 0.02). <b>Conclusions</b>: Significant disparities exist in cancer screening participation among sexual minority women in Japan, with more pronounced differences in cervical cancer screening compared to breast cancer screening. These findings highlight the need for targeted interventions addressing the unique barriers to gynecological care among sexual minority women.