Risk of clear-cell adenocarcinoma of the vagina and cervix among US women with potential exposure to diethylstilbestrol in utero

PURPOSE: Women exposed to diethylstilbestrol (DES) in utero were at elevated risk of clear-cell adenocarcinoma of the vagina and cervix (CCA) as young women. Previous research suggested that this elevated risk of CCA may persist into adulthood. We extended a published analysis to measure CCA risk as these women aged. METHODS: Standardized incidence ratios (SIR) compared CCA risk among women born from 1947 through 1971 (the DES-era) to CCA risk among the comparison group of women born prior to 1947, using registry data that covered the US population. RESULTS: Incidence rates of CCA among both cohorts increased with age. Among the DES-era birth cohort, higher rates of CCA were observed across all age groups except 55–59 years. SIR estimates had wide confidence intervals that often included the null value. CONCLUSIONS: Results are consistent with prior research and suggest an elevated risk of CCA in midlife and at older ages among women exposed in utero to DES. These results highlight unresolved issues regarding cancer risk among aging DES daughters and appropriate screening guidance. The examination of population-based cancer surveillance data may be a useful tool for monitoring trends in the incidence of other rare cancers over time among specific birth cohorts.