Bowen's disease (squamous cell carcinoma in situ) in Kauai, Hawaii. A population-based incidence report.

BACKGROUND: The incidence of Bowen's disease (squamous cell carcinoma in situ) is rarely investigated.

OBJECTIVE: Our purpose was to report the incidence of Bowen's disease in a defined Caucasian population in Kauai, Hawaii.

METHODS: We conducted a prospective 5-year population study.

RESULTS: We found 71 Caucasian residents, 44 men and 27 women, who had an initial episode of Bowen's disease during the 5-year period. The average annual incidence rate per 100,000 Caucasian residents of Kauai, standardized to the 1980 U.S. Caucasian population, was 174 for men and 115 for women, with a combined rate of 142. The incidence increased in older age groups. The mean age of the patients was 65.2 years. The most common anatomic site was the extremities. Subsequent Bowen's disease occurred in eight patients (11.3%). Recurrence after treatment developed in only one patient (1.4%). Twenty-six patients (36.6%) had concurrent skin cancers, either basal cell carcinoma or squamous cell carcinoma, or both. There was no increased incidence of internal malignancy.

CONCLUSION: The incidence of Bowen's disease is high in Caucasian residents of Kauai and is 10 times higher than that reported from a northern Midwestern community. Kauai's intense ambient UV light and greater opportunity for year-round outdoor activities likely contributes to this higher rate.