Bone and soft tissue tumors and carbon ions
Bone and soft tissue tumors (sarcomas) are rare and a typical example of disease for which conventional radiotherapy has limited effect. When surgery is difficult, there are few options besides drug therapy with low response rates, so carbon ion therapy has been considered. It is the second most treated disease at QST Hospital and the first carbon ion indication to be covered by insurance in Japan.
Indications
① Sarcoma confirmed by biopsy ② radical resection not suitable ③ local treatment judged to benefit prognosis. The sites and histological types actually treated vary.
Main target diseases
Chordoma of the sacrum is the most common. Osteosarcoma of the limbs is generally not eligible; most cases are in the trunk, such as the pelvis or around the spine, where radical resection is difficult or would cause major functional impairment. Chondrosarcoma and soft tissue sarcoma are also treated.
Preparation
Irradiating from appropriate directions is important, and because many patients have pain or neurological symptoms, making an immobilization device is a key step. QST Hospital has a rotating gantry that can irradiate from any of 360 degrees, and its use is decided by the condition. After the device is made, CT is taken on another day with the device on, and MRI or PET-CT is used if needed to define the treatment range.
Irradiation schedule
Most bone and soft tissue tumors receive 16 fractions over 4 weeks.
Side effects
If the tumor invades or is widely in contact with surrounding organs such as the digestive tract, skin, or nerves, those organs are hard to avoid. Even with a minimized irradiation range, organs within it may show damage and symptoms over time; the type and frequency depend on tumor location and treatment range.