Risk of lung cancer in pre‐ and post‐menopausal women with ano‐genital malignancies

Abstract

Women diagnosed during the period 1943–1990 and reported to the Danish Cancer Registry with invasive squamous‐cell carcinomas of the uterine cervix, vulva, vagina or anus, together with those having pre‐cancerous lesions (CIN III or carcinoma in situ) of the uterine cervix diagnosed in the period 1958–1990, were followed for the occurrence of subsequent lung cancer over 762,000 person‐years. Overall, these patients developed 2 to 2° times more lung cancers than women in the general Danish population. Women in whom cervical cancer was diagnosed recently, and before the age of 45 years, had a 4.6 times elevated risk of developing lung cancer, while young women with vulvar or vaginal cancer were at a 4.0‐fold elevated risk. Similarly, women in whom anal cancer was diagnosed before the age of 60 years were at a 3.5‐fold increased risk of developing lung cancer. The present study supports the hypothesis that smoking is involved in the aetiology of ano‐genital malignancies. The particularly high risk of developing subsequent lung cancers seen in women who were pre‐menopausal (<45 years) at the time of the ano‐genital cancer diagnosis suggests that the effect of smoking in ano‐genital carcinogenesis might be partly mediated through alterations in oestrogen metabolism. Alternatively, patients who developed their initial ano‐genital cancer at a young age might harbour some genetic susceptibility which could explain their excess lung‐cancer risk.