Second solid cancers after allogeneic hematopoietic stem cell transplantation

BACKGROUND. The objective of this study was to establish the incidence and risk factors for the development of second solid cancers after allogeneic hematopoietic stem cell transplantation (allo‐HSCT). METHODS. The authors reviewed the case files of 926 consecutive patients who underwent allo‐HSCT at their institution between 1985 and 2003. RESULTS. Twenty‐eight patients developed 30 solid malignancies at a median of 6.8 years after allo‐HSCT (range, 0.12–17.3 years) for a 10‐year cumulative incidence of 3.1% (95% confidence interval [95% CI], 2–5%; all solid tumors) and 2.3% (95% CI 1–4%; excluding basal cell carcinoma and carcinoma in situ). The risk ratio of developing a second solid malignancy after allografting, compared with the general population of British Columbia adjusted for age and sex, was 1.85 (95% CI, 1.04–3.06; P = .019). In multivariate analysis, recipient age at allo‐HSCT >40 years (P = .005) and having a woman donor (P = .0008) were associated with a greater risk of developing a second solid cancer. CONCLUSIONS. The authors concluded that patients undergoing allografting are at increased risk of developing a second solid cancer compared with the general population, particularly those of advanced age at the time of allograft. It is noteworthy that patients who had women as graft donors had an increased risk for developing a second solid cancer. This unexpected finding is a new observation and has not been reported previously. Extended follow‐up will be needed to assess more fully the incidence and risk factors for the development of solid cancers, because the latency can be prolonged. Cancer 2007. © 2006 American Cancer Society. For this large, retrospective study, the authors examined the incidence and risk factors for the development of second solid cancers after allogeneic hematopoietic stem cell transplantation. The results suggested that patients who undergo allografting are at increased risk of developing a second solid cancer compared with the general population, particularly patients of advanced age at the time of allograft and patients who receive a female graft.