BLADDER-CANCER IN VARIOUS POPULATION GROUPS IN THE GREATER DURBAN AREA OF KWAZULU-NATAL, SOUTH-AFRICA

Objective To study the incidence of different histological types of bl adder cancer in various racial groups lining within the same geographi cal region. Patients and methods The study included 615 new patients w ith bladder cancer seen at three Provincial hospitals in Durban from J anuary 1980 to January 1990. The patients were classified as Caucasian (white people of European descent), African (indigenous black people) , Asian (people originating from the Indian subcontinent) or Coloured (people of mixed race). The bladder tumours were classified according to standard histopathological criteria as transitional cell carcinoma, adenocarcinoma or sarcoma. Mixed tumours consisted of both carcinomat ous and sarcomatous or undifferentiated elements. Results Transitional cell carcinoma constituted 95% of the cancers in Caucasians, compared with only 30% in Africans, whereas squamous cell carcinoma occurred i n 53% of the African patients, but in only 2% of the Caucasians. In As ian patients, 75% of the: tumours were transitional cell and 18% were squamous cell carcinoma, whereas in Coloureds 82% were transitional ce ll and 9% squamous cell carcinoma. Undifferentiated carcinoma occurred in 8% of African and only 1% of Caucasian patients, whereas adenocarc inoma, mixed tumours and sarcoma occurred in 9% of African patients an d only 2% of Caucasian patients. Ova of Schistosoma haematobium were s een in microscopic sections of the bladder tumour in 85% of the patien ts with squamous cell carcinoma, in 50% of those with undifferentiated tumours and adenocarcinoma, in 17% of those with mixed tumours or sar coma, and in only 10% of the patients with transitional cell carcinoma . At presentation, African patients were a mean of >20 years younger t han Caucasians. In African patients with squamous cell carcinoma, 90% had stage T3 or T4 disease at presentation, whereas in Caucasian patie nts with transitional cell carcinoma 76% had stage T1 or T2 disease at presentation. From the study group, it appears that bladder cancer is about six times more common in Caucasians than in Africans. However, the value for Caucasian patients with bladder cancer probably underest imates the true value by about fine times, so that bladder cancer in t he greater Durban area may be as much as 30 times more common in Cauca sians than in Africans. Conclusion In African patients, endemic Schist osomiasis appears to be related to a high incidence of not only squamo us cell carcinoma, but also undifferentiated tumours and adenocarcinom a of the bladder. The effective management of squamous cell carcinoma of the bladder in African patients will depend on the eradication of S chistosomiasis and the early detection of bladder cancer at a stage wh en it may still be cured by radical treatment.