Epidemiology, Etiology, and Risk Factors of Gynecologic Malignancies
Overview
This domain covers the incidence, prevalence, and risk factors for gynecologic cancers: cervical, endometrial, ovarian, vulvar, and vaginal. Key concepts include HPV as the primary cause of cervical cancer (types 16 and 18 highest risk), and the role of HPV in vulvar and vaginal cancers (though less common). Endometrial cancer risk factors: unopposed estrogen, obesity, diabetes, hypertension, nulliparity, early menarche, late menopause, tamoxifen use, Lynch syndrome (hereditary nonpolyposis colorectal cancer). Ovarian cancer risk factors: nulliparity, early menarche, late menopause, infertility, BRCA1/2 mutations, Lynch syndrome; protective factors: oral contraceptives, multiparity, breastfeeding, tubal ligation. Vulvar cancer: HPV-related (younger women) and HPV-independent (older women, associated with lichen sclerosus). Vaginal cancer: rare, HPV-related, often secondary. Epidemiology: incidence and mortality trends, racial disparities (e.g., higher mortality among Black women with endometrial cancer).
Traps
Questions often test the distinction between risk factors for different cancers. A common trap is confusing endometrial and ovarian cancer risk factors: both share nulliparity and early menarche, but obesity is a stronger risk for endometrial, while BRCA mutations are stronger for ovarian. Another trap is the association of tamoxifen with endometrial cancer (increased risk) but not ovarian. Also, HPV vaccination reduces cervical cancer risk but does not eliminate it entirely. Be careful with the protective effect of oral contraceptives: they reduce ovarian and endometrial cancer risk but may slightly increase breast and cervical cancer risk.
Worked Example
A 60-year-old obese woman with diabetes and hypertension presents with postmenopausal bleeding. What is the most likely diagnosis? Endometrial cancer. Rule of thumb: The classic triad for endometrial cancer risk is obesity, diabetes, and hypertension (though not all three are required).