[Kidney transplant and cancer risk: an epidemiological study in Northern and Central Italy].

OBJECTIVE

This investigation aimed at highlighting the cancer risk of recipients of kidney transplant in northern and central Italy.

METHODS

Data on 2,120 kidney transplant recipients from Niguarda Ca' Granda Hospital Milan, or from Policlinico "A. Gemelli", Rome, were analyzed The period at risk of developing cancer (person-years, PY) was computed from 30 days after transplant to date of cancer diagnosis, or date of death, or date of re-entering dialysis, or date of last follow-up. Observed and expected numbers of cancer were compared through sex- and age-standardized incidence ratios (SIRs) and 95% confidence intervals (CIs). The transplant attributable fraction (AF) of cancer cases and incidence rate ratios (IRR) were also computed.

RESULTS

After 16.594 PY of follow-up (median flow-up: 6.8 years), 121 cancer cases were diagnosed (729.2 cases/10(5) PY). The SIR for all cancers was 1.9. Kaposi's sarcoma (KS) (27 cases observed, SIR = 82) and non-Hodgkins lymphoma (NHL) (18 cases observed a SIR = 6.4 were the most common cancers. Significantly increased SIRs were also noted for native kidney (11 cases observed SIR = 4.9), corpus uteri (6 cases observed SIR = 4.6), and liver (6 cases observed, SIR = 3.1). The transplant AF was 46.9%, largely due to KS (98.8%) and NHL (84.3%). Since SIRs decreased with increasing age, the transplant AF ranged from 73.2% below 45 years of age to 30.4% after 54. Among risk factors, area of birth strongly influenced the risk of KS, with a 3-fold higher risk in those born in the South of Italy as compared to those born in the northern part.

CONCLUSIONS

Immune depression after kidney transplantation entails a two-fold increased overall risk of cancer, mainly related to cancers associated to a viral aetiology. Furthermore, our findings suggest the need to adopt a specific serological screening for the prevention of post-transplant KS in individuals born in southern Italy.