medwireNews: Solid organ transplant recipients have a significant risk for developing Burkitt lymphoma (BL), US researchers have found.
Transplant recipients in the USA are 23 times more likely to develop BL than members of the general population, with an incidence of 10.8 cases per 100,000 person-years, say Sam Mbulaiteye (National Cancer Institute, Bethesda, Maryland, USA) and co-authors.
The team reviewed BL incidence in 203,557 solid organ recipients listed in the US Transplant Cancer Match Study of 1987 to 2009.
The incidence of BL peaked in solid organ recipients between 3 and 8 years after transplantation, contrasting with the sharp increase in risk for the virus-associated malignancies, diffuse large B-cell lymphoma and Kaposi sarcoma, 1 year after transplantation, the team reports in the American Journal of Hematology.
"This longer latency suggests that progression to BL occurs after chronic immunosuppression and chronic EBV [Epstein-Barr virus] infection," say the researchers. "Alternatively, the lower incidence of BL in the first few years after transplantation may reflect the negative impact of intense immunosuppression on progression to BL during that period."
Of note, the incidence of BL was significantly higher in patients who received their organ before the age of 18 years compared with at 35 years or older (incidence rate ratio [IRR]=3.49) and in liver or heart than kidney recipients (IRR=2.91 and 2.39, respectively), after adjusting for confounding factors.
By contrast, BL was less common in female than male recipients (IR=0.45) and in Black than White patients (IRR=0.33). Patients seropositive for EBV at baseline were also less likely to develop BL than seronegative patients (IRR=0.34).
The risk for BL was also reduced by treatment with azathioprine (IRR=0.56) and corticosteroids (IRR=0.48), the researchers say.
Mbulaiteye et al also found that 69% of 32 examined LB tumors were positive for EBV. "This suggests the presence of distinct BL entities, which may differ in etiology," they write.
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