Recently we added to the Library as well as a blog a very good individual patient meta-analysis of the use of sirolimus showing that it was associated with a reduction in cancer incidence but also with an increased rate of death after kidney transplantation. Now we have a study of data from the US transplant registry concerning the use of sirolimus and the incidence of cancer. This is a large observational study but suggests that there is not strong evidence that sirolimus prevents cancer after transplantation, although it might be advantageous in patients with a high cancer risk. However an interesting observation was that there was an increased diagnosis of prostate cancer in patients receiving sirolimus. Overall the reduction in cancer incidence, after excluding prostate cancer, was 26%. Thus again this large registry data report does not provide convincing evidence for the use of sirolimus to prevent cancer. There was no data on death rates.