Extraskeletal osteosarcomas: current update

Extraskeletal osteosarcoma is a very infrequently diagnosed soft-tissue sarcoma subtype which has identical histological features to bone osteosarcoma. However, its demographics, presentation, radiology and treatment strategy differ from those of osteosarcoma. Its diagnosis can be at times challenging due to radiological and pathological mimics which have more common incidence. A multimodality approach is essential for optimizing the outcomes in extraskeletal osteosarcoma. Although there are certain caveats on inclusion of adjuvant therapies (radiotherapy and chemotherapy), in all cases surgical resection with wide local margins is considered the gold standard for adequate local control. The outcome in advanced disease remains dismal and there is a huge unmet need for prospective studies addressing the optimal treatment strategy. In this article, we review the evidence available for the management of extraskeletal osteosarcoma.

Extraskeletal Osteosarcoma: Outcomes and the Role of Chemotherapy

OBJECTIVES

Extraskeletal osteosarcoma (EO) is a malignant neoplasm that produces osteoid, bone, and chondroid material without direct attachment to bone or periosteum. Surgical resection is the mainstay of treatment; the role of chemotherapy is not well defined. Therefore, we evaluated the impact of chemotherapy in the survival of patients with EO.

METHODS

All EO patients seen at Mayo Clinic between 1990 and 2014 were assessed. Forty-three patients were included after all archived pathology slides were reviewed to confirm the diagnosis of EO.

RESULTS

Of 43 patients, 37 patients had localized disease and 6 patients had metastatic disease at diagnosis. Chemotherapy was used in 73% and 75% of patients, respectively. Chemotherapy was predominantly anthracycline based, and included platinum in 22 patients (84%).Median overall survival (OS) and progression-free survival (PFS) were 50 months (95% confidence interval, 25-99), and 21 months (95% confidence interval, 13-not reached), respectively. There was a trend towards longer OS and PFS in patients who received chemotherapy. Those who received platinum-based therapy had remarkably prolonged OS (median, 182 vs. 18 mo; 5-year, 61% vs. 0%; P=0.01) and PFS (median, not reached vs. 10 mo; 5-year, 56% vs. 0%; P=0.005). Baseline characteristics were similar in the platinum and nonplatinum group.In patients who received chemotherapy, relapse/recurrence rate was lower in the platinum-based group (41%) as opposed to the nonplatinum-based group (100%; P=0.02). In the neoadjuvant setting, the overall response rate of platinum-containing regimens was 27%.

CONCLUSIONS

Our results suggest a clinical benefit when platinum-based chemotherapy is incorporated in the management of patients with EO. We plan to validate this further with an expanded multicenter analysis.

Establishing musculoskeletal oncology service in resource constrained country: challenges and solutions

The burden of orthopedic tumor surgery in Pakistan is not known. Similarly the number of procedures being performed for bone and soft tissue surgery are not known. This is even becoming more challenging where the existence of rules and regulations in health care are next to minimal. Furthermore data recording in our country and case registries hardly exist. Despite the lack of information and resources, with high disease burden on community, various providers provide surgical interventions every day in our settings. A lot of tumor surgery is still being done by general surgeons and general orthopedic surgeons who have little knowledge and update about musculoskeletal oncology principles. Lack of subspecialized centers and the high cost of such centers force the patients to visit these surgeons for a highly sophisticated problem like a bone tumor which is the disease of young bones. In this article we will emphasize on the difficulty in establishing an orthopedic tumor service in our part of the world and the consequences including delay in diagnosis, faulty course of management and later decline in functionality, disease progression and increased mortality. We will highlight the principles and stepwise approach of orthopedic tumor surgery and explain the difficulty encountered if these principles are not followed.