CHANGING AGE INCIDENCE AND PATHOLOGICAL TYPES OF SCHISTOSOMA-ASSOCIATED BLADDER-CARCINOMA

Purpose: The changes in certain characteristic features of schistosoma-associated bladder carcinoma are determined. Materials and Methods: A retrospective study was done of patients with schistosoma-associated bladder carcinoma treated between 1962 and 1967, and between 1987 and 1992. Results: Mean patient age increased from 47 +/- 13.6 to 53 +/- 12.2 years and the male-to-female ratio changed from 7.8:1 to 4.9:1. Tumors showed a decreased incidence of nodular (58.7% versus 83.4%) and squamous (54% versus 65.8%) cell types, and an increased incidence of papillary (34.8% versus 4.3%) and transitional (42% versus 31%) cell types. All changes were statistically significant (p < 0.05) and paralleled by an increased incidence of low degree schistosomal infestation from 18.6 to 47.8% (p < 0.05). Conclusions: The shift in age incidence and pathological findings towards those of nonschistosomal cases could conceivably be attributed to the increased incidence of low infestation in recent years. The change in male-to-female ratio is probably due to more exposure of women to schistosomal infestation than has occurred previously.