Carbon ion radiotherapy for recurrent calf myxoid liposarcoma: a case report.

Liposarcoma (LPS) is the most common soft tissue sarcoma. Myxoid LPS (MLPS) is the second most common subtype of LPS and accounts for 25% to 50% of all LPSs. Like most other soft tissue sarcomas, the mainstay of treatment for LPS is inevitably surgery. Multidisciplinary approaches, including surgery, chemotherapy, and radiotherapy, have been successful in the treatment of LPS during the last three decades. Even so, recurrence of LPS remains challenging. Carbon ion beams produce increased energy deposition at the end of their range to form a Bragg peak while minimizing irradiation damage to surrounding tissues, which facilitates more precise dosage and localization than that achieved with photon beams. Furthermore, carbon ion beams have high relative biologic effectiveness. We herein describe a patient who developed recurrent MLPS in the right calf after two surgeries and underwent carbon ion radiotherapy (CIRT), achieving complete disappearance of the tumor. The patient developed Grade 1 radiation dermatitis 30 days after CIRT, but no other acute toxicities were observed. The tumor had completely disappeared by 120 days after CIRT, and the patient remained disease-free for 27 months after CIRT. The CARE guidelines were followed in the reporting of this case.