Subsequent primary neoplasms among bone sarcoma survivors; increased risks remain after 30 years of follow-up and in the latest treatment era, a nationwide population-based study.

BACKGROUND

The long-term risks and time trends of subsequent primary neoplasms (SPNs) among Ewing (ES) and osteosarcoma (OS) survivors are not fully understood.

METHODS

We performed a nationwide study of all ES and OS patients identified in the Swedish Cancer Registry from 1958 to 2015 with up to 58 years of follow-up. The risk of SPN was compared with that of the general population using standardised incidence ratios (SIRs) and absolute excess risks (AERs).

RESULTS

One hundred and fifteen SPNs were diagnosed among 1779 patients with ES or OS, yielding an overall SIR of 2.3 (95% confidence interval (CI), 1.9-2.7). The risk remained significantly increased in the latest treatment era (SIR 2.0; 95% CI, 1.1-3.5). The highest absolute excess risks (AER) was due to breast cancer (AER 15.2/10,000 person-years; 95% CI, 5.0-29.8) followed by female genital malignancies (AER 9.5/10,000 person-years; 95% CI, 2.4-21.5). The excess breast cancer risk among ES survivors was noted also after 30 years of follow-up with 127 extra breast cancers/10,000 person-years (95% CI, 6.6-419).

CONCLUSIONS

Breast- and female genital malignancies contribute most to the excess risk of SPN among ES and OS survivors. Importantly, excess risks did not decline over calendar time or long-term follow-up.