快中子放射治疗软组织肉瘤的疗效分析

Fast neutron radiotherapy for soft tissue sarcoma

目的 回顾分析快中子与快中子、光子混合照射治疗软组织肉瘤的疗效及其影响因素。方法 52例患者共79个病灶,其中19例37个病灶采用35 MeV p→Be快中子治疗,33例42个病灶混合照射。单纯中子组剂量4.0～21.0 Gy(中位值11.7Gy)。混合照射组中子剂量3.9～16.0 Gy(中位值8.8Gy),光子剂量9.0～62.0Gy(中位值34.0 Gy),总剂量(16.5～69.4Gy,中位值42.0 Gy)。中子分次剂量0.8～1.5Gy(中位值1.2Gy),周二、五照射;光子为常规分割。结果 病灶局部控制率为48.7％,在治疗和随访中仅有24.1％的病灶出现进展。非转移性病灶、肿瘤较小以及放射治疗前手术切除是局部控制的有利因素(P<0.05)。混合照射总剂量与局部控制及无进展时间显著正相关(r_s=0.453,r=0.288,P值分别为0.001和0.032)。混合照射较单纯中子对病灶局部控制的改善接近于有显著性意义(57.1％:35.5％,X^2=3.60,P=0.058)。全组患者的1、3、5年生存率分别为57.3％、20.5％、13.7％,远地转移为主要死因。肿瘤组织学分级较低和接受混合照射的患者生存率较高。全组病灶3+4级近期放射反应发生率为2.7％,远期的为19.0％。结论 快中子治疗软组织肉瘤可以取得较好的局部控制,中子、光子混合照射有可能改善疗效,不能手术或术后残留的G1或G2级肿瘤适用于快中子治疗,放射反?

Objective To retrospectively analyze the clinical data of patients with soft tissue sarcoma treated with fast neutron (35 MeV p-Be) or mixed neutron/photon irradiation. Methods Fifty-two patients (79 foci of tumors) with soft tissue sarcoma confirmed pathologically were included. Nineteen patients(37 foci) were treated with neutron alone, to a dose of 4. 0-21. 0 Gy (median 11.7 Gy). The rest were treated with mixed neutron/photon beam, with neutron dose of 3.9-16.0 Gy (median 8.8 Gy) by 0.8-1.5 Gy (median 1.2 Gy) per fraction, twice weekly (Tuesdays and Fridays); photon 9.0-62.0 Gy (median 34. 0 Gy) by conventional fractionation. Results Local control was observed in 48.7 % of the tumors, whereas only 24.1 % of the tumors progressed during radiotherapy and follow-up. Metastasis-free lesions, small size and resection prior to neutron therapy had beneficial influence on local control(P < 0.05) . The overall dose of mixed neutron/photon beam was positively correlated with local control ( r, = 0.453, P = 0.001) and the interval to tumor progression( r = 0.288, P = 0.032). Mixed irradiation gave a borderline significant improvement of local control as compared to neutron alone( 57.1% vs35.5%, X2 =3.60, P = 0. 058). The actuarial survival rates at 1, 3 and 5 years were 57.3%, 20.5% and 13.7%, with distant metastasis being the main cause of death. Tumors with lower pathological grade and mixed neutron/photon beam radiotherapy gave an improved survival. The incidences of grade 3-4 RTOG/EORTC early and late side effects were 2.7% and 19.0%. Conclusions Fast neutron radiotherapy is locally effective for soft tissue sarcoma. Mixed neutron/photon beam irradiation may improve the results over neutron alone. Unresectable or residual G1/G2 tumor after resection are indicated for neutron therapy. The side effects of this treatment is acceptable.