Second Primary Malignancies of the Bones and Joints: More Common than Expected in Osteosarcoma Patients.

Background: Osteosarcoma is the most common primary bone tumor in children, adolescents, and young adults. Second primary malignancies (SPMs) are a potential serious long-term event that can occur in osteosarcoma survivors.

Methods: The National Cancer Institute's Surveillance, Epidemiology, and End Results 18 database was queried for all osteosarcoma cases from 2000 through 2015. Standardized incidence ratio (SIR) and absolute excess risk (AER) of SPM per 10,000 persons (AER) relative to representative population-level data were calculated across for various anatomic locations.

Results: In total, 3438 patients with osteosarcoma were identified. Of these patients, 79 (2.3%) developed SPMs, with an SIR of 2.84 (95% confidence interval [CI] 2.35 to 3.39, P < 0.0001) and an AER of 44.96. The most common SPMs were tumors of the bones or joints (SIR 73.07, CI, 38.90 to 124.94, P < 0.0001, AER 7.48), tumors of soft tissues including the heart (SIR 15.19, CI, 5.58 to 33.07, P < 0.0001, AER 3.27), and leukemia (SIR 22.28, CI, 15.03 to 31.80, P < 0.0001, AER 16.74).

Conclusion: The overall incidence of SPMs in osteosarcoma survivors was significantly higher than would otherwise be expected for this population. Considering the occurrence and targeting surveillance for SPM in the osteosarcoma patient population is warranted.