Second primary cancers after cervical intraepithelial neoplasia III and invasive cervical cancer in Southeast England.

OBJECTIVE: Multiple primary cancers may arise in an individual because they share a common environmental risk factor (such as smoking); genetic predisposition or immunodeficiency may predispose to both cancers, or treatment for one cancer may cause a second cancer. The objective of this analysis was to identify which, if any, cancers occur more often than would be expected in a cohort of women diagnosed with cervical intraepithelial neoplasia III (CIN III) and in women with invasive cervical cancer. METHODS: The Thames Cancer Registry was used to identify two cohorts of women diagnosed with either CIN III or invasive cervical cancer. The number of subsequent cancers at other sites was observed and compared to the expected number, based on relevant age-, sex-, and period-specific incidence rates. Standardised incidence rates (SIRs) were calculated assuming a Poisson distribution. RESULTS: The following cancer sites were significantly increased after a diagnosis of either CIN III or cervical cancer: anus (SIR 5.9 and 6.3, respectively), lung (SIR 1.8 and 2.5), vulva (SIR 4.4 and 1.9), vagina (SIR 18.5 and 8.0), and kidney (SIR 1.6 and 1.9). In addition, the incidence of cancers of the rectum, bladder, and connective tissue was significantly increased after invasive cervical cancer. Cervical cancers were seen significantly more often than expected after cancers of the anus and vagina. CONCLUSION: These results support the hypothesis that cancers of the cervix, anus, vulva, and vagina share common risk factors such as human papillomavirus and smoking.