University of Texas Southwestern Medical Center, Dallas, Texas.
University of Texas Southwestern Medical Center, Dallas, Texas.
Int J Radiat Oncol Biol Phys. 2017 May 1;98(1):196-205.e2. doi: 10.1016/j.ijrobp.2017.01.020. Epub 2017 Jan 12.
To evaluate the tolerability of a dose-escalated 5-fraction stereotactic body radiation therapy for partial-breast irradiation (S-PBI) in treating early-stage breast cancer after partial mastectomy; the primary objective was to escalate dose utilizing a robotic stereotactic radiation system treating the lumpectomy cavity without exceeding the maximum tolerated dose.
Eligible patients included those with ductal carcinoma in situ or invasive nonlobular epithelial histologies and stage 0, I, or II, with tumor size <3 cm. Patients and physicians completed baseline and subsequent cosmesis outcome questionnaires. Starting dose was 30 Gy in 5 fractions and was escalated by 2.5 Gy total for each cohort to 40 Gy.
In all, 75 patients were enrolled, with a median age of 62 years. Median follow-up for 5 cohorts was 49.9, 42.5, 25.7, 20.3, and 13.5 months, respectively. Only 3 grade 3 toxicities were experienced. There was 1 dose-limiting toxicity in the overall cohort. Ten patients experienced palpable fat necrosis (4 of which were symptomatic). Physicians scored cosmesis as excellent or good in 95.9%, 100%, 96.7%, and 100% at baseline and 6, 12, and 24 months after S-PBI, whereas patients scored the same periods as 86.5%, 97.1%, 95.1%, and 95.3%, respectively. The disagreement rates between MDs and patients during those periods were 9.4%, 2.9%, 1.6%, and 4.7%, respectively. There have been no recurrences or distant metastases.
Dose was escalated to the target dose of 40 Gy in 5 fractions, with the occurrence of only 1 dose-limiting toxicity. Patients felt cosmetic results improved within the first year after surgery and stereotactic body radiation therapy. Our results show minimal toxicity with excellent cosmesis; however, further follow-up is warranted in future studies. This study is the first to show the safety, tolerability, feasibility, and cosmesis results of a 5-fraction dose-escalated S-PBI treatment for early-stage breast cancer in the adjuvant setting.
评估在接受保乳手术后的早期乳腺癌患者中，采用 5 个剂量递增的立体定向体部放射治疗（S-PBI）治疗部分乳房照射的耐受性；主要目标是利用机器人立体定向放射系统在不超过最大耐受剂量的情况下，对肿瘤切除术腔进行递增剂量治疗。
符合条件的患者包括导管原位癌或非小叶上皮组织学浸润性癌，以及肿瘤大小<3cm 的 0 期、I 期或 II 期患者。患者和医生完成基线和后续美容结局问卷调查。起始剂量为 30Gy，分 5 次给予，每增加一个队列增加 2.5Gy，总剂量达到 40Gy。
共纳入 75 例患者，中位年龄为 62 岁。5 个队列的中位随访时间分别为 49.9、42.5、25.7、20.3 和 13.5 个月。仅出现 3 例 3 级毒性。整个队列中出现 1 例剂量限制毒性。10 例患者出现可触及的脂肪坏死（其中 4 例有症状）。医生在 S-PBI 基线和 6、12 和 24 个月后，分别有 95.9%、100%、96.7%和 100%的患者将美容效果评为优秀或良好，而患者则分别有 86.5%、97.1%、95.1%和 95.3%的患者将美容效果评为优秀或良好。在这些时间段，医生和患者之间的不一致率分别为 9.4%、2.9%、1.6%和 4.7%。无复发或远处转移。
剂量递增至 40Gy，分 5 次给予，仅出现 1 例剂量限制毒性。患者在手术后和立体定向体部放射治疗后的第一年感觉美容效果有所改善。我们的结果显示，在接受辅助治疗的早期乳腺癌患者中，5 个剂量递增的 S-PBI 治疗具有最小的毒性和良好的美容效果；然而，未来的研究还需要进一步的随访。这项研究首次表明，在辅助治疗中，5 个剂量递增的 S-PBI 治疗早期乳腺癌是安全、耐受、可行的，并且美容效果良好。
