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.

Doxorubicin Dose Deintensification in Pediatric Osteosarcoma, Is Less Better?

Hadeel HalalshehIntroduction We implemented new clinical practice guidelines (CPG) for patients with osteosarcoma starting in January 2009. These guidelines were based on standard European and American Osteosarcoma Study regimen, which includes six cycles of doxorubicin with a cumulative dose of 450 mg/m 2 . Aiming to reduce cardiac toxicity at our center, we opted to reduce the cumulative dose of doxorubicin to 375 mg/m 2 . Materials and Methods This is a retrospective cohort of osteosarcoma patients aged <18 years, treated at our center between 2009 and 2018. Patients were treated with unified CPG and were prospectively followed. Disease and treatment characteristics were depicted, and survival rates were calculated. When needed, comparison of survival of different groups were conducted using log-rank test. Results After a median follow-up of 43.3 months (range, 2-153 months), 79 patients were diagnosed with osteosarcoma and treated with dose-reduced doxorubicin. Median age at diagnosis was 12.8 years. At diagnosis, 58 patients (73%) had localized disease. The 5-year event-free survival (EFS) for the whole group was 50 ± 5.9%, and overall survival (OS) was 64 ± 5.7%. For patients with extremity nonmetastatic tumors ( N = 56), 5-year EFS and OS were 60 ± 6.9% and 70 ± 6.8%, respectively, and for this group of patients, response to chemotherapy was associated with better EFS ( p = 0.0048) and OS ( p = 0.013). Only two patients suffered transient cardiac dysfunction, which was resolved after treatment. Conclusion Our findings suggest that deintensification of doxorubicin may provide adequate control for pediatric osteosarcoma. In the absence of large randomized clinical trials addressing this issue, developing countries with less resources to treat patients with heart failure may consider using the lower dose.