Bone Infarct Associated Osteosarcoma: Epidemiologic and Survival Trends

Background Bone tumors are not a frequent occurrence and bone-infarct-associated sarcomas are even rarer. The prognosis of this disease is poor and its treatment remains a challenge. Nevertheless, hardly any analyses in literature report on secondary osteosarcoma (SO) on bone infarct and most of the data available do not provide sufficient details. We evaluated whether this condition could be further characterized and if prognosis could be influenced by the chemotherapy treatment. In particular, we sought to determine (1) the main features of this rare disease; (2) the overall survival (OS) rate; (3) the OS rate associated to chemotherapy treatment; (4) the correspondence between our results and published data in terms of survival. Methods We retrospectively reviewed patients admitted at Rizzoli Orthopedic Institute of Bologna between 1992 and 2018 (1465 total cases of osteosarcoma). We identified a list of 11 cases of SO on bone infarct (cohort 1). We conferred about the epidemiology, surgical and chemotherapy (ChT) treatment and surveillance of infarct-associated osteosarcoma showing the correlation to data present in literature, corresponding to 15 case reports published within 1962-2018 (cohort 2). Results (1) cohort 1 was made of 11 patients: six females and five males, median age was 55 years. Nine (81%) were grade 4, two (19%) grade 3. Tumor predominantly arise on distal femur (64%). Most of patients had localized osteosarcoma at the diagnosis (81%); resection surgery was the elective treatment (73%) followed by amputation (18%). Of 11 patients, seven received also ChT (64%). (2) Five-years OS was 62% (95% CI: 28-84). Median OS was 74 months (95% CI: 12-not reached). The cumulative incidence of cancer-related deaths (CICRD) was 37.7% (95% CI: 11.4-64.5) at 120 months. (3) In the group treated with only surgery OS was 50% at 5 years. For patients treated with any form of ChT, OS was 71% at 5 years (p=0.4773) and hazard ratio (HR) 0.56. The CICRD was 29% (at 2 years of follow-up. Instead, it was of 50% for patients treated only with surgery. (4) Median survival was 74 months and 19 months for cohort 1 and cohort 2 respectively (p=0.09). Data analysis showed a decreased HR for cohort 1 compared to cohort 2 (HR 0.378). Results confirmed also stratifying for age and ChT administration (HR 0.355). Conclusions Based on this work, our opinion is that the choice to undergo the patients to ChT combined to surgery could improve their prognosis.