Slater J D, Yonemoto L T, Rossi C J, Reyes-Molyneux N J, Bush D A, Antoine J E, Loredo L N, Schulte R W, Teichman S L, Slater J M
Department of Radiation Medicine, Loma Linda University Medical Center, CA 92354, USA.
Int J Radiat Oncol Biol Phys. 1998 Sep 1;42(2):299-304. doi: 10.1016/s0360-3016(98)00225-9.
The role and optimum dose of radiation to eradicate prostate cancer continues to be evaluated. Protons offer an opportunity to increase the radiation dose to the prostate while minimizing treatment toxicity.
Six hundred forty-three patients with localized prostate cancer were treated with protons, with or without photons. Treatments were planned with a 3D planning system; patients received 74-75 CGE (Cobalt Gray Equivalent) at 1.8-2.0 CGE per fraction. Patients were evaluated for response to therapy and treatment-related toxicity.
The overall clinical disease-free survival rate was 89% at 5 years. When post-treatment prostate-specific antigen (PSA) was used as an endpoint for disease control, the 4.5-year disease-free survival rate was 100% for patients with an initial PSA of < 4.0 ng/ml, and 89%, 72%, and 53% for patients with initial PSA levels of 4.1-10.0, 10.1-20.0, and > 20.0, respectively. Patients in whom the post-treatment PSA nadir was below 0.5 ng/ml did significantly better than those whose nadir values were between 0.51-1.0 or > 1.0 ng/ml: the corresponding 5-year disease-free survival rates were 91%, 79%, and 40%, respectively. Minimal radiation proctitis was seen in 21% of patients; toxicity of greater severity was seen in less than 1%.
Proton therapy to 74-75 CGE produced minimal treatment-related toxicity and excellent PSA normalization and disease-free survival in patients with low initial PSA levels. A prospective randomized dose-escalation trial is now underway to help define the optimum dose of radiation for patients with early stage prostate cancer.
用于根除前列腺癌的放疗作用及最佳剂量仍在评估中。质子放疗提供了一个增加前列腺放疗剂量同时使治疗毒性最小化的机会。
643例局限性前列腺癌患者接受了质子放疗，部分联合光子放疗。治疗计划通过三维计划系统制定；患者每次分次接受1.8 - 2.0 CGE（钴灰色当量），共74 - 75 CGE。评估患者的治疗反应及治疗相关毒性。
5年时总体临床无病生存率为89%。以治疗后前列腺特异性抗原（PSA）作为疾病控制终点时，初始PSA < 4.0 ng/ml的患者4.5年无病生存率为100%，初始PSA水平为4.1 - 10.0、10.1 - 20.0及> 20.0的患者相应无病生存率分别为89%、72%和53%。治疗后PSA最低点低于0.5 ng/ml的患者预后明显好于最低点在0.51 - 1.0或> 1.0 ng/ml之间的患者：相应的5年无病生存率分别为91%、79%和40%。21%的患者出现轻微放射性直肠炎；严重程度更高的毒性发生率低于1%。
对于初始PSA水平较低的患者，74 - 75 CGE的质子治疗产生的治疗相关毒性最小，PSA正常化及无病生存率良好。一项前瞻性随机剂量递增试验正在进行中，以帮助确定早期前列腺癌患者的最佳放疗剂量。
