Abstract 117P
Background
Osteosarcoma is a primary bone tumor characterized by being chemosensitive. MAP is the standard treatment which has been widely used in Instituto Nacional de Enfermedades Neoplasicas (INEN). In this abstract, we focus on evaluating the prognostic factors and outcomes in neoadjuvant treatment at INEN.
Methods
We conducted a retrospective analysis of all non-metastatic osteosarcoma patients seen at INEN in Lima-Peru between November 2014 to February 2023. We report patients with the following criteria: (1) typical histological and radiological features of primary central high-grade osteosarcoma; (2) age >14 years; (3) primary tumor located in the extremities; (4) no previous treatment, (5) non-metastatic tumors and (6) all patients treated by MAP regimen. Survival analysis was performed using Kaplan Meier Stimate, also we made bivarial analysis using mortality as event of interest versus other characteristics of the patient, chemotherapy and surgery, a value of p<0.05 was considered as significant.
Results
A total of 47 non-metastatic osteosarcoma cases were identified. Median age at diagnosis was 19.4 years (range: 14-36) and thirty-four percent (n=16) of patients were older than 20 years-old at the time of diagnosis and 63.83% (n=30) of the patients were male. 60% (n=28) had radical surgery and 40% (n=18) had sparing surgery. In a bivariate analysis, we found an association between mortality and time of recurrence (p=0.02), chemotherapy toxicity (p=0.026) and number of chemotherapy (p=0.033). More than 50% of patients without joint involvement were alive at 2 years and those with involvement died entirely (p = 0.02). Based on this, joint involvement represents a 3.55-fold increased risk of mortality in the follow-up period [HR=3.55; p=0.036; IC95% (1.08-11.64)]. The OS at 20 months was 48.15% and while the OS at 24 months was 25.93%.
Conclusions
This is the first study describing the outcomes of neoadjuvant treatment with MAP regimen non-metastatic OS in Peru. We found that patients with joint involvement had a worse prognosis in terms of OS. Mortality increases after 20 months of follow-up. Further studies are required to explain this increase in mortality.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.