Volumetric Modulated Arc Radiotherapy for Resected HighGrade Costal Chondrosarcoma with Positive Margins: A Case Report and Review of Literature

Chondrosarcomas are cartilage-matrix-forming tumors that make up 30% of primary malignant bone tumors and are the third most common primary bone malignancy after multiple myelomas and osteosarcomas. Although wide en bloc surgical excision offers the best chance for a cure, achieving negative surgical margins can be challenging because of the high morbidity of surgery in different anatomic areas. Therefore, adjuvant radiation therapy plays an important role in improving the local control rate when negative margins are not achieved. However, delivery of a sufficient dose of radiation can be difficult because of the proximity to normal organs/tissues that are sensitive to radiation therapy and therefore dose-limiting. New techniques such as Volumetric Modulated Arc Therapy (VMAT) allow us to achieve an optimal conformation of the radiation beam, avoiding healthy organs and minimizing the undesirable acute and chronic side effects. We report a case of costal chondrosarcoma with positive post-surgery margins treated with adjuvant radiation therapy using VMAT technique that appears free of disease two years after finishing radiation therapy with a mild asymptomatic radiation-induced pneumonitis as the only late side effect.