Mark H. Greene

OBJECTIVE: Etanercept and infliximab are tumor necrosis factor (TNF) antagonists that have been recently approved for the treatment of rheumatoid arthritis (RA) and Crohn's disease (CD). This study was undertaken to investigate the occurrence of lymphoproliferative disorders in patients treated with these agents. METHODS: Relevant data in the MedWatch postmarket adverse event surveillance system run by the US Food and Drug Administration were reviewed. RESULTS: We identified 26 cases of lymphoproliferative disorders following treatment with etanercept (18 cases) or infliximab (8 cases). The majority of cases (81%) were non-Hodgkin's lymphomas. The interval between initiation of therapy with etanercept or infliximab and the development of lymphoma was very short (median 8 weeks). In 2 instances (1 infliximab, 1 etanercept), lymphoma regression was observed following discontinuation of anti-TNF treatment, in the absence of specific cytotoxic therapy directed toward the lymphoma. CONCLUSION: Although data from a case series such as this cannot establish a clear causal relationship between exposure to these medications and the risk of lymphoproliferative disease, the known predisposition of patients with RA and CD to lymphoma, the known excess of lymphoma in other immunosuppressed populations, and the known immunosuppressive effects of the anti-TNF drugs provide a biologic basis for concern and justification for the initiation of additional epidemiologic studies to formally evaluate this possible association.

Fanconi anemia (FA) is an autosomal recessive condition associated with congenital abnormalities, progressive pancytopenia, and a predisposition to leukemia and solid tumors. We studied a retrospective cohort of North American patients with FA. We calculated relative risks of cancer compared to the general population and cause-specific hazards of the first major adverse outcomes of FA: bone marrow transplantation (BMT) for marrow complications, acute myeloid leukemia (AML), solid tumors, or death from bone marrow failure. We also estimated the cumulative incidence of each adverse event in the presence of the competing risks. Among 145 patients with FA, 9 developed leukemia and 14 developed a total of 18 solid tumors. The ratio of observed to expected cancers (O/E ratio) was 50 for all cancers, 48 for all solid tumors, and 785 for leukemia; these increased risks were statistically significant. The highest solid tumor O/E ratios were 4317 for vulvar cancer, 2362 for esophageal cancer, and 706 for head and neck cancer. Cause-specific hazards of both death and AML peaked at 1%/y in teenage years; the hazard of BMT peaked at 4%/y at age 7. In contrast, the hazard of a solid tumor approached 8%/y by age 40 years. The cumulative incidence to age 48 was 10% for leukemia, 11% for death from marrow failure, 29% for a solid tumor, and 43% for BMT. The risk of a solid tumor may become even higher as death from aplastic anemia is reduced and as patients survive longer after BMT.

The risk of hereditary cutaneous malignant melanoma was evaluated in 401 members of 14 families with an autosomal dominant form of melanoma. We documented 127 primary melanomas in 69 family members, including 39 new melanomas diagnosed in 22 study participants from the time of first examination through a maximum of 8 years of follow-up. The 39 newly diagnosed melanomas occurred only in family members with dysplastic nevi, a known precursor of familial melanoma. Of 77 patients with dysplastic nevus syndrome without prior melanomas, 4 developed their first melanoma during prospective follow-up, as compared with 0.03 cases expected. The prospective age-adjusted incidence for melanoma was 14.3/1000 patients with dysplastic nevus per year, with a cumulative melanoma risk (+/- SE) of 7.2% (+/- 3.6) at 8 years. The actuarial probability of melanoma developing in family members with dysplastic nevi was 56.0% (+/- 10.1) from age 20 to age 59. This study confirms that dysplastic nevi are clinical markers of high risk for, and precursors of, hereditary melanoma.