Oncological and functional outcome of periosteal osteosarcoma.

BACKGROUND: Periosteal osteosarcoma is an uncommon variant of osteosarcoma which constitutes less than 2% of all osteosarcomas. Whereas adequate surgical excision remains the cornerstone of treatment, the role of chemotherapy in this tumor is still unclear. Existing literature contains very few single center studies on the outcomes for periosteal osteosarcomas and any additional information will help in better understanding of these uncommon lesions. This study aims to evaluate the oncologic and functional outcomes of treatment of periosteal osteosarcoma treated at our institute.

MATERIALS AND METHODS: A retrospective analysis of 18 cases of periosteal osteosarcoma treated between January 2001 and December 2010 was carried out. There were 12 males and 6 females. The mean age at presentation was 16.3 years (range 5-26 years). Tibia and femur were the most common sites (n = 8). 16 of 18 patients received chemotherapy, 16 had limb sparing resection, one had an amputation and one had rotationplasty. Of the 16 patients with limb salvage, conventional wide excision was done in 11 cases. In 5 cases tumor was excised with hemicortical excision. Of the 11 cases treated with wide excisions, 4 patients underwent an osteoarticular resection and in 7 patients a joint preserving segmental intercalary resection was done.

RESULTS: All patients were available for followup. Surgical margins were free in all patients. A good response to chemotherapy was seen in 4/11 cases and poor in 6/11 cases. In one case the histological response was not discernible due to predominant chondromyxoid nature of the tumor. The median followup was 61 months (range: 18-130 months). There were two local recurrences (11%) at 9 and 18 months postsurgery. Pulmonary metastasis subsequently occurred in 4 cases (22%). Fourteen patients are currently alive and continuously disease free. Disease free survival at 5 years was 77.8% and overall survival (OVS) was 83.3%. Patients without marrow involvement had a better OVS at 5 years when compared with patients with marrow involvement (90% vs. 75%) (P = 0.23).

CONCLUSION: Surgical excision remains the mainstay of treatment. Intramedullary involvement may suggest aggressive disease biology. The role of chemotherapy is still debatable and multicenter studies are needed to provide guidelines.