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Objective:To compare dose distributions between photon versus proton and carbon ion radiotherapy (particle therapy, PT) among patients with gross tumors, and to evaluate the safety and efficacy of PT for thymic malignancies (TM).Methods:From Sept 2015 to Aug 2018, 19 patients with TM who underwent non-palliative PT using pencil beam scanning technique in our hospital and had at least one follow-up were retrospectively analyzed. Diseases staged from Ⅰ-Ⅳ B including 15 Ⅲ-Ⅳ B. All the patients had pathological diagnosis with 10 thymomas, 6 carcinomas and 3 neuroendocrine tumors of the thymus. A set of dosimetric comparisons were conducted in patients with gross tumors at a total dose of 66 GyE, in 33 fractions for photon or proton beams and in 22 fractions for carbon ion beams. Five patients without any local treatment and 7 patients after R2 resection received radical radiotherapy of proton 44.0-48.4 GyE in 20-22 fractions plus carbon ion 21.0-23.1 GyE in 7 fractions, 1 case after complete resection (R0 resection) had proton 45 GyE in 25 fractions, 5 cases after R1 resection had proton 60.0-61.6 GyE in 28-30 fractions and 1 case of recurrence after postoperative radiotherapy had only carbon ion 60 GyE in 20 fractions. Results:The median follow up time was 19.0 (2.4-42.9) months. There were 13 patients with gross tumors, with a median largest diameter of 5.7 (2.7-12.8) cm. The dosimetric study showed that proton and carbon-ion plans significantly reduced the maximum dose to the spinal cord, the mean doses to the organs at risk (OARs) including the lung/heart/esophagus, and the integral dose of the exposed area about 25%-65% compared to photon plans. No other toxicities ≥ grade 3 were observed except one myocardial infarction (grade 4 late toxicity). There was no local failure observed. Metastasis to regional lymph node, lung, pleura, skull base, bone or liver occurred in 4 patients with Ⅲ-Ⅳ B stage disease in 6.1-22.8 months after treatment. The 2-year local control and overall survival rates were 100%, disease free survival and distant metastasis free survival rates were 64.6%. Conclusions:For TMs, PT has significant advantages over photon in terms of sparing OARs, and is safe and effective in patients with TMs after short-time follow-up.
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Objective@#To verify the safety and efficacy of IONTRIS particle therapy system (IONTRIS) in clinical implementation.@*Methods@#Between 6.2014 and 8.2014, a total of 35 patients were enrolled into this trial: 31 males and 4 females with a median age of 69 yrs (range 39-80). Ten patients had locally recurrent head and neck tumors after surgery, 4 cases with thoracic malignancies, 1 case with hepatocellular carcinoma, 1 case with retroperitoneal sarcoma, and 19 cases with non-metastatic prostate carcinomas. Phantom dose verification was mandatory for each field before the start of radiation.@*Results@#Twenty-two patients received carbon ion and 13 had proton irradiation. With a median follow-up time of 1 year, all patients were alive. Among the 16 patients with head and neck, thoracic, and abdominal/pelvic tumors, 2, 1, 12, and 1 cases developed complete response, partial response, stable disease, or disease progression, respectively. Progression-free survival rate was 93.8% (15/16). Among the 19 patients with prostate cancer, biological-recurrence free survival was 100%. Particle therapy was well tolerated in all 35 patients. Twenty-five patients (71.4%) experienced 33 grade 1 acute adverse effects, which subsided at 1 year follow-up. Six (17.1%) patients developed grade 1 late adverse effects. No significant change in ECOG or body weight was observed.@*Conclusions@#IONTRIS is safe and effective for clinical use. However, long term follow-up is needed to observe the late toxicity and long term result.