Keegan THM, et al. - Researchers carried out this study to determine the survival impact of second primary malignant neoplasms (SPMs) in adolescents and young adults (AYAs) (15-39 years) compared with that of pediatric (<15 years) and older adult (≥40 years) patients with the same SPMs. As per findings, substantial adverse impact of SPMs on survival was evident for AYAs. This may somewhat explain the relative lack of survival improvement in AYAs compared with other age groups.

Methods

• Researchers performed a population-based, retrospective cohort study of patients with cancer, diagnosed from 1992 to 2008 and followed through 2013, in 13 Surveillance, Epidemiology and End Results regions in the United States.
• They performed data analysis from June 2016 to January 2017.
• For this study, five-year relative survival was calculated overall and for each cancer occurring as a primary malignant neoplasm (PM) or SPM by age at diagnosis.
• Using multivariable Cox proportional hazards regression, they examined the impact of SPM status on cancer-specific death.

Results

• Researchers included 15,954 pediatric, 125,750 AYAs, and 878,370 older adult patients diagnosed as having 14 cancers occurring as a PM or SPM.
• After an SPM, 5-year survival was 33.1% lower for children, 20.2% lower for AYAs, and 8.3% lower for older adults compared with a PM at the same age.
• The absolute difference in 5-year survival for the most common SPMs in AYAs was 42% lower for secondary non-Hodgkin lymphoma, 19% for secondary breast carcinoma, 15% for secondary thyroid carcinoma, and 13% for secondary soft-tissue sarcoma.
• Younger vs older patients, for thyroid, Hodgkin lymphoma, non-Hodgkin lymphoma, acute myeloid leukemia, soft-tissue sarcoma, and central nervous system cancer, indicated significantly worse survival by SPM status.
• Compared with AYAs with the same PMs, adolescents and young adults with secondary Hodgkin lymphoma (hazard ratio [95% CI], 3.5 [1.7-7.1]); soft-tissue sarcoma (2.8 [2.1-3.9]); breast carcinoma (2.1 [1.8-2.4]); acute myeloid leukemia (1.9 [1.5-2.4]); and central nervous system cancer (1.8 [1.2-2.8]) experienced worse survival.