A preliminary result of the international IMPACT study has shown recently that inherited mutations of the BRCA1 or BRCA2 genes (already described in some families with breast and ovarian cancers) are associated with PC in a smaller number of cases, but have a higher proportion of aggressive disease [15]. There are ongoing research studies aiming at identifying genes associated with an increased risk of PC. These could be located on chromosome 17 and may also include HPC1, HPC2, HPCX and CAPB. Some gene overexpression (FUT8) was suggested in recent studies to be associated with the more aggressive PC [16] and with the progression to the androgen-independent state [17].

So far there is no evidence of their role. In a very large European Prospective Investigation into Cancer and Nutrition (EPIC) which included 150,000 men, it appeared that high intake of protein from dairy products had a link with the occurrence of PC [18]. Lycopene (tomatoes) could be protective, but the literature has provided inconsistent results [19, 20], while selenium and vitamin E did not show any protective effect in the large SELECT prospective clinical trial [21, 22].

Firefighters may be at risk due to their exposure to toxic combustion products [23, 24]. Exposure to heavy metals (cadmium) has also been incriminated [25], but the Strong Heart Mortality study did not show any significant association between cadmium and PC mortality [26].

Studies have shown conflicting data and no evidence that link PC and sexually transmitted diseases, prostatitis, vasectomy, obesity or smoking. An epidemiologic study has linked the high incidence of PC in the French West Indies to chlordecone (Kepone^®) use, an oestrogenic organophosphorate pesticide formerly extensively used in banana plantations in Martinique and Guadeloupe and now internationally banned [27]. However multivariate analysis showed that this association was stronger in subjects aged 60 years or older, in men with a family history of prostate cancer and in those who had previously lived in Western countries.

Chemoprophylaxis with finasteride and dutasteride is not recommended due to their side effects and the lack of sufficient data relating to specific mortality [28, 29].