Malignancies of the colorectum and anus in solid organ recipients.

Patients undergoing solid organ transplantation (SOT) are at increased risk for developing malignancies due to the long term immunosuppression. Data on malignancies of the large intestine after various types of SOT are rare. A total of 3595 SOTs were performed between 1986 and 2005 at our center and retrospectively analyzed with regard to the incidence and course of malignancies of the colon, rectum, and anus. Standard immunosuppression consisted of calcineurin inhibitors in combination with azathioprine or mycophenolate mofetil and steroids with or without antithymocyte globulin or IL-2 receptor antagonist induction. A total of 206 patients (5.7%) developed malignancies. Colorectal adenocarcinoma was diagnosed in nine patients (0.25%; mean age at diagnosis 65 years) at a mean of 5.3 years after transplantation. Five patients (55%) died 7.2 years post-transplant due to cardiovascular disease (n = 4) and tumor progression (n = 1). Four patients developed anal neoplasia (0.11%) 7 years post-transplant with 100% 1-year survival. Five patients showed post-transplant lymphoproliferative disorders (PTLD) with intestinal involvement. The incidence of anal but not of colorectal cancers in our transplant recipients differed from that of immunocompetent individuals of corresponding age (0.11% vs. 0.002% and 0.25% vs. 0.3%). PTLD may involve the colon.