Malignancies in renal transplant recipients in Hong Kong

Abstract

From 1972 to 2000, 1714 renal transplants were registered in Hong Kong. Forty-two post-transplant malignancies were reported. The overall incidence of malignancy was 2.4%. The risk ratio was 4.8 when compared with the general population. The corresponding ratio for females is higher. The majority of the malignancies developed within the first five post-transplant years, especially the first year, but the cumulative probability of developing malignancy increased with time. The overall mortality and malignancy related mortality were 40.5% and 33.3% respectively. Post-transplant lymphoproliferative disease (PTLD), hepatocellular carcinoma (HCC) and Kaposi's sarcoma accounted for 28.6%, 14.3% and 7.1% of all the tumors and were the major causes of malignancy related deaths. Two groups of PTLD were observed. Those PTLD developed within the first post-transplant year had aggressive disease and high mortality. Extra-nodal involvement was found in 75% of patients, the commonest of which being the graft and the brain. Disseminated disease and central nervous system (CNS) involvement carried the worst prognosis. HCC was related to hepatitis B antigen positivity. Routine screening of serum alpha-fetoprotein was helpful in early diagnosis and treatment, thus favoring the outcome. Kaposi's sarcoma was highly related to the over- immunosuppressive state. Withdrawal or reduction of immunosuppression may induce complete remission at the cost of graft loss.