Abstract 741P
Background
Osteosarcoma (OS) is the most common primary bone sarcoma. As a rare cancer, large-scale studies are limited. Since recent studies reported genetic differences in elderly and younger patients with OS, we examined the nationwide statistics for OS in Japan with special emphasis on the difference of patient demographics, treatment, and survival according to different age groups using the Bone and Soft Tissue Tumor (BSTT) Registry.
Methods
We identified 3446 patients with OS in the BSTT Registry during 2006-22, which is a nationwide organ-specific cancer registry for bone and soft tissue tumors in Japan. We extracted data on patient demographics, treatment, and prognosis for each patient.
Results
OS showed a slight male preponderance (57%). The age distribution had 2 peaks (10’s and 70’s). The proportion of elderly cases aged ≥60 years increased from 16% (2006-12) to 19% (2013-22). The most commonly bones of involvement included femur (46%), tibia (18%), and humerus (9%) overall, while one third of the elderly cases developed OS either the spine or pelvis. Nodal and distant metastasis at diagnosis was found in 3% and 19%, respectively, both of which are more common in elderly patients (5% vs 2%; 26% vs 17%). Surgery of the primary tumor/chemotherapy was performed in 79%/83% of the patients aged <60 years and 61%/47% in elderly patients, suggesting less intensive treatment in elderly patients. Overall survival (OAS) at 5-year was 64% and elderly patients showed poorer 5-year OAS (40%) compared with those in patients aged <60years (70%). We found other significant factors associated with OAS: histologic grade, nodal and distant metastasis at diagnosis, tumor size and location, and surgical margin. Although not significant (P=0.080), recent cases (2013-22) had poorer OAS compared with those diagnosed during 2006-12.
Conclusions
The present study provided an overview of the epidemiology, clinical features, treatment, and prognosis of patients with OS in Japan, especially highlighting the quite different profiles between elderly patients and younger patients. It is essential to document our data regarding the outcomes of elderly patients so that other countries showing similar population aging trends can learn from our experiences.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Asahi Kasei Pharma.
Disclosure
K. Ogura: Financial Interests, Personal, Advisory Board: Asahi Kasei Pharma. All other authors have declared no conflicts of interest.