The prognostic importance of clinicopathological factors in patients with osteosarcoma who received neoadjuvant therapy; a single center experience
Authors: Şimşek Fatih , Majidova Nargiz , Kırcalı Muhammed Fatıh , Yaşar Alper , Çelebi Abdussamet , Sever Nadiye , Işık Selver , Ercelep Özlem , Sarı Murat , Bayoğlu İbrahim Vedat , Kostek Osman 
Published: November 2023

Objectives
Osteosarcoma is the most prevalent primary malignancy of the bone. It has worse prognosis in adult patients but cure is possible even in the metastatic stage. Survival rates have been significantly improved with systemic chemotherapy. In this study, we aimed to investigate the effects of epidemiological and clinicopathological factors on overall survival (OS) and disease-free survival (DFS) in 77 osteosarcoma patients who received neoadjuvant treatment and were treated and followed up in our center.
Methods
This study retrospectively evaluated the effects of epidemiological and clinicopathological factors on OS and DFS times in 77 osteosarcoma patients. The patients were 18 years of age and over, applied to the Marmara University Faculty of Medicine Medical Oncology outpatient clinic between 2001 and 2022. They underwent neoadjuvant treatment at the time of diagnosis or during follow-up.
Results
The gender distribution of the patients was 44 (57.1%) men and 33 (42.9%) women. The median age of patients at diagnosis was 18 (range, 10–75) years. There were 3 patients (3.9%) with ECOG-performance score 1–2 and 74 (96.1%) patients with ECOG-performance score 0. There were 67 (87%) patients with negative surgical margins (R0) and 2 (2.6%) patients with positive margins (R1/2). While complete pathological response was achieved in 9 patients (11.7%), 59 patients (76.6%) had residual. Among the 24 (31.2%) patients with necrosis rate of 90% or more following neoadjuvant therapy, 6 (25.0%) patients received cisplatin + doxorubicin and 17 (70.8%) patients received PEI (epirubicin + cisplatin + ifosfamide) regimens. 38 patients (49.4%) had disease recurrence or progression. The overall 5-year DFS rate is 35.5%. Men had 5-year DFS rate of 20.9%, while women had a rate of 53.2%. Patients with primary tumor location in the pelvis had a 5-year DFS rate of 20.0%, whereas patients with a primary location outside the pelvis had a DFS rate of 36.6%. After neoadjuvant therapy, patients with a necrosis rate of 90% or more had a 5-year DFS rate of 54.0%, while patients with a necrosis rate of less than 90% had a rate of 31.6%. 5-year OS among the patients under 30 years old at diagnosis was 58.1% and the rate of 5-year OS among the patients 30 years and older at diagnosis was 31.9%. Men had a 5-year OS rate of 37.0%, compared to women's 5-year OS rate of 71.2%. In this study, the 5-year OS rate was 26.7% in patients with the primary lesion site of pelvis, compared to 54.4% in extra-pelvic primary location. In patients who received neoadjuvant, the 5-year OS rate was 54.0% in patients with negative surgical margins and 0% in patients with positive surgical margins. The 5-year OS rate was 71.9% in patients with a necrosis rate of 90% or more after neoadjuvant therapy, and 35.4% in patients with a necrosis rate of less than 90%.
Conclusion
Significant prognostic indicators for DFS were found to be female gender, primary pelvic location, and completion of adjuvant therapy in patients who underwent surgery after neoadjuvant therapy. The completion of adjuvant chemotherapy in patients who underwent surgery after neoadjuvant therapy and a necrosis rate of 90% or more in the pathology report were discovered to be significant prognostic markers for OS.