Bilharziasis and bladder cancer: a time trend analysis of 9843 patients

ABSTRACT

To explore any changes in bladder carcinoma during 37 years period, in regard to its frequency, bilharzia association, histological profile and demographic data. This is a retrospective study on 9843 patients treated at the National Cancer Institute [NCI], Cairo University, during the years 1970-2007. Three groups were selected series [A] included 3212 patients during 1970-1974, series [B] 3988 patients during 1985-1989 and series [C] 2643 patients during 2003-2007. For statistical analysis, data of series [A], [B] and [C] were compared to determine the significance of difference [p value 0.005]. A significant decline of the relative frequency of bladder cancer was observed from 27.63% in the old series to 11.7% in the recent series. Bilharzia association dropped from 82.4% to 55.3%. There was a significant rise of transitional cell carcinomas from 16.0% to 65.8%, becoming at present the most common tumor type, with a significant decrease in squamous cell carcinomas from 75.9% to 28.4%. There was an increase in the median age of patients from 47.4 years to 60.5 years and a decrease of male female [M/F] ratio from 5.4 to 3.3. The decline in the relative frequency of bladder cancer is associated with a decline in bilharzia egg positivity in the specimen and is probably related to better control of bilharziasis in the rural population in Egypt. This was accompanied by a change in the histological profile of tumors, with significant predominance of transitional cell carcinoma and an increase in the age of patients, a pattern rather similar to that in western reports