From Logistic regression model, adjusted for age (by five years age band) and sex.The control groups are constituted of other cancers excluding cancers of the liver, kidney, thyroid, lymphomas and myelomas.The reference groups (or unexposed to dialysis) Include all cancer cases, or all other cancer cases diagnosed m the Varese cancer registry m the period 1983-87.Table : Risk of developing cancer in patients on dialysis considered.44 023 patient years were available for the study, 25 684 in men and 18 339 in women.479 cases of cancer at all sites was recorded.The average age at diagnosis was 59-5 years and the cases were on dialysis for an average of 6-37 years.There were statistically significantly raised risks of primary liver cancer, kidney cancer, thyroid cancer, lymphoma, and multiple myeloma.There were significantly decreased risks of cancers of the oral cavity and larynx, and a non-significant decrease in cancer of the oesophagus (table ).The excess of non- Hodgkin's lymphoma is similar to that found in recipients of renal transplants.The excess of liver cancer might be linked to materials used during dialysis.Longer and better survival of patients with end stage renal disease undergoing renal replacement therapy means that there are many elderly patients receiving therapy.Our results highlight the need for careful follow-up and for early detection of cancers in these patients.