Vicini Frank A, Remouchamps Vincent, Wallace Michelle, Sharpe Michael, Fayad Julie, Tyburski Laura, Letts Nicola, Kestin Larry, Edmundson Gregory, Pettinga Jane, Goldstein Neal S, Wong John
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan, USA.
Int J Radiat Oncol Biol Phys. 2003 Dec 1;57(5):1247-53. doi: 10.1016/s0360-3016(03)01573-6.
We present our ongoing clinical experience utilizing 3D conformal radiation therapy (3D-CRT) to deliver partial-breast irradiation (PBI) in patients with early-stage breast cancer treated with breast-conserving therapy.
Thirty-one patients referred for postoperative radiation therapy after lumpectomy were treated with PBI using our previously reported 3D-CRT technique. Ninety-four percent of patients had surgical clips outlining the lumpectomy cavity (mean: 6 clips). The clinical target volume (CTV) consisted of the lumpectomy cavity plus a 10-mm margin in 9 patients and 15-mm margin in 22 (median: 15 mm). The planning target volume consisted of the CTV plus a 10-mm margin for breathing motion and treatment setup uncertainties. The prescribed dose (PD) was 34 or 38.5 Gy (6 patients and 25 patients, respectively) in 10 fractions b.i.d. separated by 6 h and delivered in 5 consecutive days. Patients were treated in the supine position with 3-5 beams (mean: 4) designed to irradiate the CTV with <10% inhomogeneity and a comparable or lower dose to the heart, lung, and contralateral breast compared with standard whole-breast tangents. The median follow-up duration is 10 months (range: 1-30 months). Four patients have been followed >2 years, 6 >1.5 years, and 5 >1 year. The remaining 16 patients have been followed <12 months.
No skin changes greater than Grade 1 erythema were noted during treatment. At the initial 4-8-week follow-up visit, 19 patients (61%) experienced Grade 1 toxicity and 3 patients (10%) Grade 2 toxicity. No Grade 3 toxicities were observed. The remaining 9 patients (29%) had no observable radiation effects. Cosmetic results were rated as good/excellent in all evaluable patients at 6 months (n = 3), 12 months (n = 5), 18 months (n = 6), and in the 4 evaluable patients at >2 years after treatment. The mean coverage of the CTV by the 100% isodose line (IDL) was 98% (range: 54-100%, median: 100%) and by the 95% IDL, 100% (range: 99-100%). The mean coverage of the planning target volume by the 95% IDL was 100% (range: 97-100%). The mean percentage of the breast receiving 100% of the PD was 23% (range: 14-39%). The mean percentage of the breast receiving 50% of the PD was 47% (range: 34-60%).
Utilizing 3D-CRT to deliver PBI is technically feasible, and acute toxicity to date has been minimal. Additional follow-up will be needed to assess the long-term effects of these larger fraction sizes on normal-tissue sequelae and the impact of this fractionation schedule on treatment efficacy.
我们展示了我们正在进行的临床经验，即利用三维适形放射治疗（3D-CRT）对接受保乳治疗的早期乳腺癌患者进行部分乳腺照射（PBI）。
31例接受肿块切除术后放射治疗的患者采用我们先前报道的3D-CRT技术进行PBI治疗。94%的患者有手术夹标记肿块切除腔（平均：6个夹子）。临床靶体积（CTV）在9例患者中由肿块切除腔加10毫米边缘组成，在22例患者中加15毫米边缘（中位数：15毫米）。计划靶体积由CTV加10毫米边缘组成，以应对呼吸运动和治疗摆位不确定性。处方剂量（PD）分别为34或38.5 Gy（分别为6例和25例患者），分10次，每天两次，间隔6小时，连续5天给予。患者仰卧位接受3 - 5束射线（平均：4束）照射，旨在以<10%的不均匀性照射CTV，与标准全乳切线照射相比，对心脏、肺和对侧乳腺的剂量相当或更低。中位随访时间为10个月（范围：1 - 30个月）。4例患者随访>2年，6例>1.5年，5例>1年。其余16例患者随访<12个月。
治疗期间未观察到大于1级红斑的皮肤变化。在最初4 - 8周的随访中，19例患者（61%）出现1级毒性反应，3例患者（10%）出现2级毒性反应。未观察到3级毒性反应。其余9例患者（29%）未观察到明显的放射效应。在6个月（n = 3）、12个月（n = 5）、18个月（n = 6）以及治疗后>2年的4例可评估患者中，美容效果均被评为良好/优秀。CTV的100%等剂量线（IDL）的平均覆盖度为98%（范围：54 - 100%，中位数：100%），95% IDL的平均覆盖度为100%（范围：99 - 100%）。计划靶体积的95% IDL的平均覆盖度为100%（范围：97 - 100%）。接受100% PD的乳腺平均百分比为23%（范围：14 - 39%）。接受50% PD的乳腺平均百分比为47%（范围：34 - 60%）。
利用3D-CRT进行PBI在技术上是可行的，且迄今为止急性毒性极小。需要进一步随访以评估这些较大分割剂量对正常组织后遗症的长期影响以及这种分割方案对治疗疗效的影响。
