Comparative Analysis of Skip Metastasis in Pediatric Osteosarcoma: Clinical Features and Outcomes.

BACKGROUND: Skip metastasis (SM) is a synchronous regional bone metastasis. Using new imaging modalities, the detection of SM is easier and possibly more common. We reviewed patients with SM and compared their characteristics and outcomes to other patients with osteosarcoma treated at our center. METHODS: We reviewed retrospectively children (<18 years) with newly diagnosed osteosarcoma who presented from June 2006 to March 2022. Patients' characteristics, treatment modalities, and outcomes were analyzed. All cases were discussed in a multidisciplinary clinic that included 2 experienced radiologists. RESULTS: We identified 155 patients with osteosarcoma, among which 13 (8.3%) patients had SM detected by MRI. Patients with SM had a median age at diagnosis of 11.2 years (range 7 to 17). Three patients had lung metastasis at diagnosis. Bone scan was positive for the SM in 8 patients (62%). All patients underwent primary tumor resection after neoadjuvant chemotherapy (amputation in 5, limb salvage surgery in 8). Five had postchemotherapy necrosis ≥90% in primary tumor. Seven patients relapsed/progressed (1 local and 6 in the lung), all relapsed patients died of disease. Compared to the rest of the patients, those with SM had similar clinical features to patients without SM; outcomes were similar with no significant differences in event-free survival and overall survival ( P =0.7 and 0.3, respectively). CONCLUSION: In this study, we observed a percentage of patients with SM comparable to previous reports. Patients with SM exhibited clinical features akin to the rest of our patients. Thorough evaluation of imaging studies and multidisciplinary care, coupled with meticulous surgical planning, are crucial for achieving a cure, which remained unjeopardized in our patients with SM.

Progression before local control in osteosarcoma: Outcome and prognosis-predictive factors.

BACKGROUND: The prognosis and impact of early disease progression in patients with osteosarcoma prior to local control (LC), and the potential therapeutic benefits of ifosfamide/etoposide (IE) remain underexplored in the medical literature. METHODS: A retrospective study was conducted on pediatric patients (≤18 years) with osteosarcoma who presented to King Hussein Cancer Center between June 2006 and March 2022. We studied patients with disease progression before LC. RESULTS: Among 195 patients, 31 (17males) exhibited disease progression before LC. The median age at diagnosis was 14.1 years, and patients were followed for a median of 23.1 months (range: 5.8-94.7). The majority of tumors were located in the extremities (n = 28). Ten patients (48%) had lung-only metastasis. Twenty-five patients showed progression at the local site only, and six showed progression both at local/metastatic sites. For the 25 patients with local-site-only progression, the decision for 24 was immediate LC via LSS (n = 9), amputation (n = 10), hemimandibulectomy (n = 1), and radiation therapy (n = 1). Three families refused amputation. Among the six patients with combined local/metastatic site progression, the decision was for two to intensify chemotherapy by adding IE, while the other four were recommended immediate LC. However, two of them refused surgery. In total, five patients received IE as intensification for progression, all of whom subsequently progressed. The 5-year event-free survival and overall survival were 27.2% and 31.3%, respectively. CONCLUSION: Our findings suggest that early disease progression before LC in patients with osteosarcoma is associated with poor prognosis. However, patients initially diagnosed with localized disease and who later exhibited local-disease-only progression appeared to have better outcomes. The potential role of IE in the treatment of patients exhibiting early progression merits further investigation in a larger study cohort.