Summary A bladder cancer conference sponsored by the U.I.C.C. and others was held in Leeds in September 1971, and considered both the clinical and scientific aspects of the disease. The more purely scientific contributions have been summarised elsewhere (European Journal of Cancer 1972). The papers of clinical interest emphasised the occupational hazards in the tailoring industry, in hairdressers, in nurses, in the leather industry and in certain Japanese silk painters. It seems likely that the overall incidence of bladder tumours is gradually increasing and that there is likely to be an association with smoking. Emphasis was given to the importance of medical surveillance not only of workers in the dye industry but also of those using the finished products. The role of bilharzia in the production of bladder cancer was considered and it is believed that this is associated with an increase in squamous but not in transitional cell carcinomas. The immunological consequences of radiotherapy were discussed and evidence was produced that high-energy radiation reduces the cellular response for the period of irradiation, though cytotoxic lymphocytes develop again soon after treatment ceases. If the cytotoxic response decreases again following radiotherapy it is usually associated with the appearance of metastases or local recurrence. Patients who maintain high levels of cytotoxicity remain clinically tumourfree. The clinical papers emphasised the diverse nature of the treatments available. In terms of 5-year survival they highlighted again the fact that many forms of treatment can be used to control the superficial (stage T1) tumours whilst, for the advanced (stage T4) lesions, no treatment is effective. The 3- and 5-year survivals for stage T2 and stage T3 lesions are so similar, despite the different forms of treatment used, that it seems likely that it is impossible clinically to differentiate these 2 stages. Since the 5-year survival following the different forms of treatment is so similar it may be thought unlikely that any of the treatments used significantly modifies the natural course of the disease. There is certainly no strong evidence to suggest that primary cystectomy for stage T, lesions when compared with the results following a radical course of high-energy radiation, justifies the high immediate surgical mortality and long-term morbidity. On the other hand, if the results following pre-operative radiotherapy and cystectomy reported by Bloom are maintained in a larger series, the picture may well change. In our opinion the results presented at the conference suggest that the best form of primary treatment yet available for invasive tumours of the bladder is external and/or interstitial radiotherapy, with the exception of those patients presenting with bilateral ureteric obstruction. One notable feature of this conference was the lack of any contribution relating to the use of cytotoxic chemotherapy in the management of bladder tumours.