New malignancies after blood or marrow stem-cell transplantation in children and adults: incidence and risk factors.

PURPOSE: To determine the incidence and risk factors for the development of new malignancies occurring after stem-cell transplantation (SCT).

PATIENTS: Between January 1, 1974, and March 31, 2001, 3,372 patients underwent SCT at the University of Minnesota. From these transplants, 147 posttransplant malignancies (PTMs) were identified in 137 patients.

RESULTS

Excluding nonmelanoma skin cancers (n = 19) and carcinoma-in-situ (n = 5), the remaining 123 cases represented an 8.1-fold (95% confidence interval [CI], 6.7 to 9.6) increased risk of a PTM, an excess risk of 102.7 cases/10,000 persons/yr (age and sex adjusted). This includes a significantly elevated risk for developing myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML; standardized incidence ratio [SIR] = 300; 95% CI, 210 to 406), non-Hodgkin's lymphoma including posttransplant lymphoproliferative disorder (PTLD; SIR = 54.3; 95% CI, 39.5 to 41.1), Hodgkin's disease (SIR = 14.8; 95% CI, 3.9 to 32.9), or solid tumors overall (SIR = 2.8; CI, 2.0 to 3.7) and in specific for melanoma, brain, and oral cavity tumors. The cumulative incidence for the development of any PTM was 6.9% (95% CI, 5.2 to 8.6) at 20 years post-SCT. For PTLD (n = 43), the cumulative incidence plateaued at 1.4% (95% CI, 1.0 to 1.8) by 10 years post-SCT. For MDS or AML, the cumulative incidence plateaued at 1.4% (95% CI, 0.9 to 1.9) by 10 years post-SCT. The cumulative incidence of developing a solid tumor did not plateau and was 3.8% (95% CI, 2.2 to 5.4) at 20 years post-SCT.

CONCLUSION

These data reveal that the risk of PTMs, especially solid tumors, continues to increase even 20 years after transplant, necessitating long-term close follow-up for these patients.