Cancer risk potential bladder

Thus, in assessing potential bladder cancer risk for humans based on studies in rodents, consideration of a threshold dose response is the foremost consideration. The differences in composition of the urine, anatomic differences, and especially exposure differences between rodents and humans must be taken into account. Furthermore, the evidence for a relationship for urinary tract calculi to an increased risk of bladder cancer is relatively weak and is complicated by the usual association of bacterial cystitis with the presence of long-standing calculi. Urinary precipitate and crystals are not relevant to human carcinogenesis, in contrast to rodents. 

An additional variable not dealt with completely in these risk analyses, is the expected type of tuoior. The tumors produced in the mouse were hemangioendotheliomas in the abdominal organs and tissues. Aniline residues passing through the human bladder are suspect as having the potential of producing more serious tumors at this site. This variable adds to the uncertainty of cancer risk assessment for human exposure based on laboratory animal data. 

Based on current evidence, the International Agency for Research on Cancer (IARC) has stated (IARC 1984) that the available epidemiological studies provide limited evidence that certain exposures in the aluminum production industry are carcinogenic to humans, giving rise to cancer of the lung and bladder. A possible causative agent is pitch fume. It is important to emphasize that the potential risk of cancer in... 

Public concern has focused on the possible carcinogenic effects of drugs and other chemicals. Long-term chronic toxicity studies in a variety of species have been started in the hope of minimizing potential risk of cancer in man. However, the results of such studies are difficult, sometimes impossible, to interpret. Yet their economic impact can be enormous, as shown by the withdrawal of cyclamates when bladder cancer was observed in a limited number of rodents. Inevitably drugs will be affected too already the safety of certain oral contraceptives has been questioned because of possible carcinogenic effects in the breasts of dogs after extended use. 

---