Background: In recent years, modifications of treatment protocols introduced in pediatric oncology have resulted in a significant improvement in treatment outcomes. Unfortunately, the probability of subsequent malignant neoplasm (SMN) in this group of patients is 3 to 6 times higher than the general age-matched population. In this study, we sought to evaluate the treatment options for patients with secondary bone tumors after prior anti-cancer therapy.
Materials and methods: Twenty-four patients (median age 12.9 years) with subsequent malignant bone tumors were treated according to oncological guidelines for bone sarcoma during the period 1991-2020. All patients had a standard tumor imaging and laboratory evaluation. All toxicities were documented.
Results: The median time from the first neoplasm to SMN was 7.6 years (range 2.4 to 16.3 years). All patients received chemotherapy and underwent surgery as a local control procedure. Two patients with Ewing sarcoma had additional radiation on the tumor bed. A complete response was achieved in 20 patients. With a median follow-up of 18.3 years (range 5.7 to 40.3 years), 18 patients (75%) are alive. The estimated 5-year post-subsequent bone malignant neoplasm survival was 74.5% (95% CI 55-95%). Fourteen patients required chemotherapy dose modification, and doxorubicin was discontinued in seven patients. One patient required a renal transplant two years after treatment. There were no other significant toxicities.
Conclusions: The treatment of bone SMNs can be effective, although in many patients it is necessary to reduce the doses of drugs. Early detection and aggressive treatment can improve the outcome.
Keywords: adolescents; bone tumors; children; multimodal therapy; subsequent malignant neoplasm.