Secondary hematopoietic malignancies in survivors of childhood cancer: an analysis of 111 cases from the Surveillance, Epidemiology, and End Result-9 registry

Abstract

Background: Studying secondary hematological malignancies in a large cohort of patients can help predict risks and trends associated with current therapies.

Methods: The authors analyzed data from the Surveillance, Epidemiology, and End Resultsecondary 9 (SEER-9) database on patients with a primary malignancy (diagnosed before the age of 20 years) between 1973 and 2005 who developed a secondary hematological malignancy. Primary cancer and histological subtype, incidence, risk factors, outcomes, and changes in risk patterns of secondary hematological malignancies were analyzed for 1973 to 1985, 1986 to 1995, and 1996 to 2005. Standardized incidence ratios (SIRs) of observed to expected cancers were calculated.

Results: Of 34,867 patients with a histology-confirmed primary malignancy, 111 developed secondary hematological malignancies (median, 44 months). Lymphoma was the commonest primary cancer (n = 47). The main histological subtype of secondary hematological malignancy was acute myeloid leukemia (AML) (49%), which had the shortest median latency time and the worst 5-year survival (18% ± 5.3%; P = .044). Secondary Hodgkin lymphoma had the best 5-year survival (83% ± 15%). The 5-year overall survival for patients with secondary hematological malignancies was 31% ± 4.7%. The risk of secondary AML steadily increased from 1986 to 2005, whereas SIRs for acute lymphoblastic leukemia did not change over time. Non-Hodgkin lymphoma, the second most common secondary hematological malignancy, occurred at a median of 112 months, and its risk steadily increased over time periods.

Conclusions: Childhood cancer survivors are at increased risk of developing secondary hematological malignancies, particularly secondary AML. This risk has continued to rise even in recent years, emphasizing the need to study other factors contributing to secondary hematological malignancies and closely monitor these patients.