The subsequent risk of internal cancer with Bowen's disease. A population-based study
C. G. Chute, T. Y. Chuang, E. J. Bergstralh and W. P. Su
Department of Health Sciences Research, Mayo Clinic, Rochester, Minn.
OBJECTIVE--To address the subsequent risk of internal cancer in a
population-based cohort of patients with Bowen's disease. DESIGN--Incident
cases of skin cancers other than malignant melanoma occurring in a defined
population were classified as basal cell carcinoma, squamous cell
carcinoma, or Bowen's disease. Through medical records, all patients were
followed up for the development of subsequent internal cancer until they
died, moved from Rochester, Minn, or January 1, 1986, whichever came first.
Incidence rates of skin cancer and subsequent cancer were computed; the
subsequent rate of internal cancer was compared with that prevailing in the
community. PATIENTS--Enrolled were all permanent residents in the
population base of Rochester, Minn, who developed basal cell carcinoma (n =
657), squamous cell carcinoma (n = 169), or Bowen's disease (n = 71) on the
basis of pathologic examination and clinical presentation from 1976 through
1984. MAIN OUTCOME MEASURE--The relative risk of subsequent internal cancer
among patients with Bowen's disease compared with that of the population
base from which they arose was 1.1 (95% confidence limits, 0.5, 1.6).
RESULTS--Annual incidence rates, adjusted to the 1980 US white population,
were 14.9 per 100,000 for Bowen's disease, 38.8 for squamous cell
carcinoma, and 146 for basal cell carcinoma. The estimated relative risk
for subsequent cancer was 0.9 (95% confidence limits, 0.5, 1.6) among
patients with squamous cell carcinoma and 1.0 (95% confidence limits, 0.7,
1.3) for patients with basal cell carcinoma. These risks were not
significantly different for various durations of follow-up or for
sun-exposed vs sun-protected sites. CONCLUSIONS--We find no evidence in
these population-based cohort data of and increased risk of subsequent
internal cancer associated with Bowen's disease or other forms of
nonmelanomatous skin cancer.
