Radiation Medicine Program, University of Toronto Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.
Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.
Int J Radiat Oncol Biol Phys. 2020 Nov 1;108(3):676-685. doi: 10.1016/j.ijrobp.2020.04.044. Epub 2020 May 11.
Neoadjuvant chemotherapy (NAC) is standard of care for locally advanced breast cancer. There is wide variation in radiation therapy (RT) practice and limited data describing locoregional relapse (LRR) after NAC. We hypothesized a low LRR risk with modern NAC, surgery, and RT and aimed to elucidate patterns of LRR and predictors of disease-free survival (DFS) and overall survival (OS) in these patients.
Data from 416 patients with stage II/III breast cancer treated between 2008 and 2015 with NAC, surgery, and adjuvant RT were reviewed retrospectively. DFS and OS rates were calculated using the Kaplan-Meier method. The LRR rate was estimated using the cumulative incidence function, treating death as a competing risk. Multivariable survival analysis was performed using Cox regression.
Median follow-up was 4.7 years. Most patients had cT2/3 (74%) cN1 (61%) disease and underwent mastectomy (75%) and axillary dissection (84%). Pathologic complete response (pCR) was achieved in 22% of patients. There were 27 LRRs (including 4 isolated LRRs) and 89 distant failures. Two patients developed LRR 2 months after surgery, before adjuvant RT. LRR could be mapped in 23 patients: most (20) recurred within the RT field; 1 in- and out-of-field; and 2 out-of-field. Five-year LRR, DFS, and OS were 6.4%, 77%, and 90%, respectively. On multivariable analysis, triple-negative subtype (hazard ratio [HR] 2.82; 95% confidence interval [CI], 1.78-4.47; P < .001), stage III disease (HR 1.72; 95% CI, 1.11-2.69; P = .016), and non-pCR (HR 4.76; 95% CI 2.13-10.0; P < .001) were associated with poor DFS and OS (HR 4.13 [95% CI, 2.21-7.72; P < .001]; HR 1.94 [95% CI, 1.001-3.75; P = .049]; and HR 2.38 [95% CI, 0.98-5.88; P = .055], respectively).
Patients with breast cancer treated with modern NAC, surgery, and RT have a low 5-year LRR risk, with the majority occurring in-field. Triple-negative subtype, stage III disease, and non-pCR were associated with inferior DFS and OS.
新辅助化疗（NAC）是局部晚期乳腺癌的标准治疗方法。放疗（RT）的实践存在广泛差异，且关于 NAC 后局部区域复发（LRR）的数据有限。我们假设在现代 NAC、手术和 RT 治疗下，LRR 的风险较低，并旨在阐明这些患者的 LRR 模式和无病生存（DFS）和总生存（OS）的预测因素。
回顾性分析了 2008 年至 2015 年间接受 NAC、手术和辅助 RT 治疗的 416 例 II/III 期乳腺癌患者的数据。使用 Kaplan-Meier 法计算 DFS 和 OS 率。使用累积发病率函数估计 LRR 率，将死亡视为竞争风险。使用 Cox 回归进行多变量生存分析。
中位随访时间为 4.7 年。大多数患者患有 cT2/3（74%）cN1（61%）疾病，并接受了乳房切除术（75%）和腋窝清扫术（84%）。22%的患者达到了病理完全缓解（pCR）。有 27 例 LRR（包括 4 例孤立性 LRR）和 89 例远处失败。有 2 例患者在手术后 2 个月，在辅助 RT 之前发生 LRR。在 23 例患者中可以绘制 LRR：大多数（20 例）在 RT 野内复发；1 例在野内和野外；2 例在野外。5 年 LRR、DFS 和 OS 分别为 6.4%、77%和 90%。多变量分析显示，三阴性亚型（HR 2.82；95%CI，1.78-4.47；P<.001）、III 期疾病（HR 1.72；95%CI，1.11-2.69；P=0.016）和非 pCR（HR 4.76；95%CI，2.13-10.0；P<.001）与较差的 DFS 和 OS 相关（HR 4.13[95%CI，2.21-7.72；P<.001]；HR 1.94[95%CI，1.001-3.75；P=0.049]；和 HR 2.38[95%CI，0.98-5.88；P=0.055]）。
接受现代 NAC、手术和 RT 治疗的乳腺癌患者 5 年 LRR 风险较低，大多数发生在野内。三阴性亚型、III 期疾病和非 pCR 与较差的 DFS 和 OS 相关。
