Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas.
Department of Breast Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas.
Pract Radiat Oncol. 2019 Jan;9(1):e4-e13. doi: 10.1016/j.prro.2018.08.003. Epub 2018 Aug 17.
This study aimed to prospectively characterize toxicity and cosmesis after accelerated partial breast irradiation (APBI) with 3-dimensional conformal radiation therapy (CRT) or single-entry, multilumen, intracavitary brachytherapy.
A total of 281 patients with pTis, pT1N0, or pT2N0 (≤3.0 cm) breast cancer treated with segmental mastectomy were prospectively enrolled from December 2008 through August 2014. APBI was delivered using 3-dimensional CRT (n = 29) or with SAVI (n = 176), Contura (n = 56), or MammoSite (n = 20) brachytherapy catheters. Patients were evaluated at protocol-specified intervals, at which time the radiation oncologist scored cosmetic outcome, toxicities, and recurrence status using a standardized template.
The median follow-up time is 41 months. Grade 1 seroma and fibrosis were more common with brachytherapy than with 3-dimensional CRT (50.4% vs 3.4% for seroma; P < .0001 and 66.3% vs 44.8% for fibrosis; P = .02), but grade 1 edema was more common with 3-dimensional CRT than with brachytherapy (17.2% vs 5.6%; P = .04). Grade 2 to 3 pain was more common with 3-dimensional CRT (17.2% vs 5.2%; P = .03). Actuarial 5-year rates of fair or poor radiation oncologist-reported cosmetic outcome were 9% for 3-dimensional CRT and 24% for brachytherapy (P = .13). Brachytherapy was significantly associated with inferior cosmesis on mixed model analysis (P = .003). Significant predictors of reduced risk of adverse cosmetic outcome after brachytherapy were D0.1cc (skin) ≤102%, minimum skin distance >5.1 mm, dose homogeneity index >0.54, and volume of nonconformance ≤0.89 cc. The 5-year ipsilateral breast recurrence was 4.3% for brachytherapy and 4.2% for 3-dimensional CRT APBI patients (P = .95).
Brachytherapy APBI is associated with higher rates of grade 1 fibrosis and seroma than 3-dimensional CRT but lower rates of grade 1 edema and grade 2 to 3 pain than 3-dimensional CRT. Rates of radiation oncologist-reported fair or poor cosmetic outcomes are higher with brachytherapy. We identified dosimetric parameters that predict reduced risk of adverse cosmetic outcome after brachytherapy-based APBI. Ipsilateral breast recurrence was equivalent for brachytherapy and 3-dimensional CRT.
本研究旨在前瞻性地描述 3 维适形放射治疗（CRT）或单入口、多腔、腔内近距离放射治疗的加速部分乳房照射（APBI）后的毒性和美容效果。
2008 年 12 月至 2014 年 8 月期间，共前瞻性地纳入了 281 例接受节段性乳房切除术的 pTis、pT1N0 或 pT2N0（≤3.0 cm）乳腺癌患者。APBI 采用 3 维 CRT（n=29）或 SAVI（n=176）、Contura（n=56）或 MammoSite（n=20）近距离放射治疗导管进行。患者按方案规定的时间间隔进行评估，在此期间，放射肿瘤学家使用标准化模板对美容效果、毒性和复发情况进行评分。
中位随访时间为 41 个月。与 3 维 CRT 相比，近距离放射治疗的 1 级浆液瘤和纤维化更为常见（浆液瘤为 50.4%比 3.4%；P<0.0001，纤维化为 66.3%比 44.8%；P=0.02），但 1 级水肿与 3 维 CRT 相比更为常见（17.2%比 5.6%；P=0.04）。3 维 CRT 的 2-3 级疼痛更为常见（17.2%比 5.2%；P=0.03）。3 维 CRT 的 5 年美容效果较差的医生报告率为 9%，而近距离放射治疗为 24%（P=0.13）。混合模型分析显示，近距离放射治疗与美容效果较差显著相关（P=0.003）。接受近距离放射治疗后，皮肤 0.1cc（皮肤）≤102%、最小皮肤距离>5.1 mm、剂量均匀指数>0.54 和非一致性体积≤0.89 cc 是降低不良美容效果风险的显著预测因素。近距离放射治疗组和 3 维 CRT 组的同侧乳房复发率分别为 4.3%和 4.2%（P=0.95）。
与 3 维 CRT 相比，近距离放射治疗的 1 级纤维化和浆液瘤发生率更高，但 1 级水肿和 2-3 级疼痛发生率更低。近距离放射治疗后的美容效果较差的医生报告率较高。我们确定了预测近距离放射治疗后美容效果不良风险降低的剂量学参数。同侧乳房复发在近距离放射治疗和 3 维 CRT 之间是等效的。
