(P 037) SURVIVAL OUTCOMES AND POST-SURGICAL MORBIDITY BASED ON SURGICAL APPROACH TO PULMONARY METASTASECTOMY IN PATIENTS WITH OSTEOSARCOMA

Objective: Although thoracoscopy is the recommended surgical approach for lung cancer, thoracotomy is considered the standard approach for the management of pulmonary metastases in osteosarcoma (OST). Several studies have identified the advantages of a thoracoscopy approach, however, the clinical significance of thoracotomy compared to thoracoscopy has yet to be evaluated in a randomized control trial. The objective of this study was to retrospectively compare outcomes and morbidity according to the approach for surgical management of pulmonary metastases in OST.

Methods: A single-institution retrospective medical record review of all patients with OST diagnosed between January 1, 2004-December 31, 2018, who underwent pulmonary metastasectomy (PM) for metastases at primary diagnosis or first relapse. Data on surgical approach, post-operative complications and survival outcomes were analyzed. The log-rank test was utilized to evaluate differences in survival outcomes between disease characteristics. Fisher’s exact test and Kruskal-Wallis sum rank test was used to evaluate post operative complications, as appropriate.

Results: 61 patients with OST underwent PM. 21 patients were metastatic at diagnosis and underwent PM during primary treatment; 9 had thoracotomy, 6 thoracoscopy and 6 combined thoracoscopy with thoracotomy (CTT). There was no difference in survival outcomes between surgical approaches. The 2-year event-free survivals [EFS] for thoracotomy, thoracoscopy and CTT were 42%, 33%, 50%, respectively; p=0.85 (Fig 1); 2-year overall survival (OS) was 64%, 83%, 83%, respectively; p=0.61. There were significantly more pneumothoraces (PTX) with thoracotomy compared to thoracoscopy or CTT (100%, 80%, 50% respectively; p=0.02). Less patients had chest tubes placed with thoracoscopy compared to thoracotomy or CTT (60% vs. 100%, 100% respectively; p=0.036), with no significant difference in the duration of chest tube or hospitalization days. Pain was comparable in all groups (91% thoracotomy, 40% thoracoscopy, 88% CTT; p=0.09). No patients had post-operative infections (PI) and there was no significant difference in Foley catheter (FC) use (27%, 0%, 38%, respectively; p=0.4).
43 patients with first pulmonary relapse or progression underwent PM; 18 had thoracotomy, 16 thoracoscopy and 9 CTT with no significant difference in survival outcomes. The 2-year EFS for thoracotomy, thoracoscopy, CTT were 23%, 47%, 25%, respectively; p=0.363 (Fig 2); 2-year OS was 93% vs 78% vs 58%, respectively; p=0.59). There were no PI in this group. However, there were more PTX in thoracotomy and CTT compared to thoracoscopy (90%, 100% vs. 56%, respectively; p=0.012), and a greater incidence of FC use in thoracotomy vs thoracoscopy and CTT (35% vs. 0%, 13%, respectively; p=0.01). The incidence of chest tube placement was comparable in all groups (p=0.72). There was significantly less pain for thoracoscopy compared to thoracotomy or CTT (22% vs. 90%, 88%, respectively; p< 0.001). There were longer median durations of hospitalization in the CTT group compared to other surgical approaches (6 vs 4 days, p=0.03).

Conclusion: Our patients with OST pulmonary metastases have comparable poor outcomes despite varying surgical approaches to pulmonary metastasectomy. As in previously published studies, we demonstrate that there are more significant post-operative complications (PTX, FC use, and pain) associated with thoracotomy for PM in OST. While our study reinforces the clinical equipoise between thoracotomy and thoracoscopy, we could not assess for surgical bias and other competing risks given the limitations of a retrospective study. This will be addressed in the ongoing Children’s Oncology Group trial AOST2031 (NCT05235165), a prospective randomized clinical trial evaluating outcomes between thoracotomy and thoracoscopy in the management of pulmonary metastases for OST.

Figure 1-CTOS 2022_Kuo-Mascarenhas.docx

Figure 2-CTOS 2022_Kuo-Mascarenhas.docx