Long-Term Incidence of Secondary Malignancies after Allogeneic Hematopoietic Cell Transplantation: A Single-Center Experience.

To review the emergence of secondary malignancies (SMs) in recipients of allogeneic hematopoietic cell transplantation (HCT), we documented the occurrence of SMs in 2415 allogeneic HCT recipients, ages 18 to 71, in a single center over 4 decades. SMs were seen in 209 patients, including 58 with nonmetastatic squamous cell (SCC) and basal cell carcinoma (BCC) of the skin. Cumulative incidence of SM was 6.3% at 10 years, 13.5% at 20 years, and 17.6% at 30 years post-HCT. Median age at diagnosis of SMs was 61 years (range, 21 to 85). By multivariable analysis, older age at HCT was the only independent prognostic factor for SM (HR, 1.39 for ages 41 to 55 and HR, 1.92 for age > 55 compared with age ≤ 40; P = .001). The rate of SM (excluding nonmetastatic SCC/BCC of skin) after HCT was 2.07 times higher (P = .01) compared with the general population. Overall survival (OS) after diagnosis of SM (excluding nonmetastatic SCC/BCC of skin) was 58% at 5 years and 50% at 10 years postdiagnosis. Eastern Cooperative Oncology Group (ECOG) score was the only independent predictor of OS on multivariable analysis, with over 2-fold increased risk of death for patients with an ECOG score of 1 and over 6-fold for ECOG scores of 2 to 4, compared with ECOG score 0 (P < .0001). Forty of 209 patients (19%) diagnosed with SMs subsequently developed another new malignancy. OS was 68% and 51% at 5 and 10 years, respectively. The survival of SM patients post-HCT is favorable, thus warranting diligent long-term cancer screening and standard of care treatment. ECOG status of these patients is a predominant prognostic factor.