[Urinary schistosomiasis and cancer].

The existence of a link between urinary schistosomiasis (US) and bladder carcinoma was first suspected by C. Goebel in 1905. In 1911, A.R Ferguson, who was a professor of Pathology and Microbiology at the Faculty of Medicine in Cairo, published a more detailed survey from 40 autopsies, and reported a likely association of bladder carcinoma with granulomas caused by US. Subsequently, published results from several studies reinforced Ferguson's hypothesis. Moreover, in most countries where US was endemic, association of high prevalence of bladder carcinoma with US had been pointed out. A further circumstantial evidence was a higher prevalence of bladder squamous cell carcinoma in areas endemic for SU, whereas urothelial carcinomas were more prevalent in areas which were free of SU. However, evidence of a positive correlation between SU and bladder carcinoma was delivered only many decades later, following the results from case-control studies which were adjusted on age, sex, type of dwelling and tobacco consumption. During SU, the mechanisms underlying the onset of bladder carcinoma are still poorly understood due to the lack of any convenient animal model. Classically, two processes are thought to be involved. Chronic inflammation inside bladder would be caused by granulomas centered by eggs, and would result in a neoplasmic evolution, after years. Moreover, alteration of the bladder dynamics would elicit urine stasis which in turn would cause repeated infection of bacterial or viral origin. Beside the high prevalence of squamous cell type, the natural history of bladder carcinomas caused by SU is similar to that of other malignant tumors of the bladder. Also the treatment and prognosis are identical. Albeit genital involvement is very frequent during SU, Schistosoma haematobium does not appear to be a cause of cancers of genital organs. Schistosoma mansoni and S. japonicum have been suspected to be associated with liver or colic carcinomas, but epidemiological studies have not yielded any firm evidence so far. The entire sequencing of S. haematobium genome, along with the recent availability of a more efficient mouse model, must provide a better understanding of the genesis of bladder carcinomas during SU. However, the key for a sharp decrease in both morbidity and mortality due to SU-linked carcinomas lies in a better control of haematobium schistosomiasis, such as observed in Egypt since 1970.