放射治疗四肢软组织肉瘤优于传统放疗

    IMRT bests conventional radiation for soft-tissue sarcomas of the extremities

    亚特兰大——美国放射肿瘤学会（ASTRO）年会上陈述的一项最新研讨显现，调强放疗（IMRT）对四肢软安排肉瘤部分操控效果显著优于传统放疗。

    纽约留念斯隆-凯特琳癌症中间放射肿瘤教授Kaled M. Alektiar医师陈述称，IMRT 5年部分操控率为92.4%,而外照耀放疗（EBRT）为85%.即便IMRT医治患者多为危险程度较高者，IMRT仍可使患者获益。“IMRT医治患者≥3级缓慢淋巴水肿发病率显著较低。”

    研讨者评价了320例承受确定性手术和放疗的原发性非转移性四肢软安排肉瘤患者的状况。其间155例承受传统EBRT,一般为三维适形放疗，别的165例承受MIRT.大都肿瘤（74.7%）坐落下肢，45.6%的肿瘤直径≥10 cm,92.2%坐落深部安排，82.5%为高度恶性，40%接近或阳性手术切缘。大都患者（75.9%）承受了辅佐化疗。

    IMRT组患者阳性或接近切缘的份额显著高于传统EBRT组（47.9% vs. 31.6%;P=0.003），承受IMRT患者多为安排学高度恶性，虽然两组区别仅为显著性临界水平（86.7% vs. 78.1%;P=0.055）。

    此外，更多IMRT组患者承受了术前放疗（21.2% vs. 3.2%;P<0.001）。两组患者在生齿统计学、肿瘤巨细、深度以及医治预备期间CT使用等其他方面未见区别。

    中位随访时刻49.5个月（IMRT组和EBRT组分别为42个月和87个月）。IMRT组和EBRT组5年部分复发率分别为7.6%和15%,两组中位部分复发时刻均为18个月。合计8例患者需求截肢，其间IMRT组3例，EBRT组5例。

    多变量分析标明，可显著猜测部分复发的3个要素分别为IMRT[危险比（HR），0.46;P=0.02）、年纪<50岁（HR,0.44;P=0.04）和肿瘤最长维度10 cm（HR,0.53;P=0.05）。

    IMRT 组和EBRT组5年总生存率分别为69.1%和75.6%,无显著区别。

    两组患者3级或4级急性毒性（包含感染、非感染创伤并发症和放射性皮炎）发作率类似。IMRT组患者医治间隔时刻显著较短，均匀0.8天，而传统EBRT组为2.2天。IMRT组无1例患者发作缓慢≥3级淋巴水肿，而传统EBRT组有4例患者（P=0.053）。

    该研讨由纽约维尔康奈儿医学院临床与转化科学中间赞助，Aktiar医师陈述无有关利益冲突。

    By: NEIL OSTERWEIL, Internal Medicine News Digital Network

    ATLANTA – Intensity-modulated radiation therapy proved significantly better than conventional radiation for local control of soft-tissue sarcomas of the extremities, according to new study results, investigators reported at the annual meeting of the American Society for Radiation Oncology.

    The 5-year local control rate with intensity-modulated radiation therapy （IMRT） was 92.4%, compared with 85% for external-beam radiation therapy （EBRT）， said Dr. Kaled M. Alektiar, a radiation oncologist at Memorial Sloan-Kettering Cancer Center in New York.

    The benefits of IMRT were seen despite a preponderance of higher risks in patients treated with IMRT. And, “the morbidity profile, especially for chronic lymphedema of grade 3 or higher, was significantly less,” Dr. Alektiar said.

    He and his coinvestigators looked at 320 patients who underwent definitive surgery and radiation therapy at Memorial Sloan-Kettering for primary, nonmetastatic soft-tissue sarcomas of the extremities. Of this group, 155 received EBRT with a conventional technique, usually three-dimensional conformal radiation, and 165 patients received IMRT.

    Most of the tumors （74.7%） were in the lower extremity, 45.6% were at least 10 cm in diameter, 92.2% were in deep tissue, 82.5% were high grade, and 40% had close or positive surgical margins. The majority of patients （75.9%） received adjuvant chemotherapy.

    There were significantly more patients with positive or close margins in the IMRT group than in the conventional EBRT group （47.9% vs. 31.6%; P = .003）， and more patients treated with IMRT had high-grade histology tumors, although this difference had only borderline significance （86.7% vs. 78.1%; P =.055）。

    Additionally, significantly more patients in the IMRT group received preoperative radiation （21.2% vs. 3.2%; P less than .001）。 Otherwise, the groups were balanced in terms of demographics, tumor size, depth, and use of CT in treatment planning.

    The median follow-up was 49.5 months （42 months for patients treated with IMRT, and 87 months for those treated with EBRT）。 The 5-year local recurrence rates were 7.6% for IMRT and 15% for conventional EBRT. The median time to local recurrence was 18 months in each group.

    Eight patients required amputations for salvage, including three in the IMRT cohort and five in the conventional radiation cohort.

    In multivariate **ysis, three factors that were significantly prognostic for local failure were IMRT （hazard ratio, 0.46; P = .02）， age less than 50 years （HR, 0.44; P = .04）， and a tumor size of 10 cm or less in the longest dimension （HR, 0.53; P = .05）。

    Overall survival at 5 years was 69.1% for IMRT and 75.6% for EBRT, a difference that was not significant.

    Rates of grade 3 or 4 acute toxicities, including infected and noninfected wound complications and radiation dermatitis, were similar between the groups. Patients treated with IMRT had significantly shorter treatment interruptions, at a mean of 0.8 days, compared with 2.2 days for patients treated with conventional EBRT. Chronic grade 3 or higher lymphedema did not occur in any patients treated with IMRT, compared with four patients treated with conventional EBRT （P = .053）。

    The study was supported by a grant from the Clinical and Translational Science Center at Weill Cornell Medical College, New York. Dr. Aktiar reported having no relevant financial disclosures.