Department of Radiation Oncology, BC Cancer, Vancouver, British Columbia, Canada; University of British Columbia, Vancouver, British Columbia, Canada.
Department of Cancer Surveillance and Outcomes, BC Cancer, Vancouver, British Columbia, Canada.
Int J Radiat Oncol Biol Phys. 2022 Mar 15;112(4):861-869. doi: 10.1016/j.ijrobp.2021.10.149. Epub 2021 Nov 8.
Randomized clinical trials have shown that regional nodal irradiation (RNI) in patients with unselected N1 breast cancer improves breast cancer-specific survival. However, the benefit of RNI in women with biologically low-risk N1 breast cancer is uncertain. We conducted a population-based study to determine whether RNI is associated with improved breast cancer recurrence-free interval (BCRFI) in this population.
Patients aged 40 to 79 years with pT1-2 pN1 (node-positive) breast cancer diagnosed between 2005 and 2014 were identified. The inclusion criteria were modeled off of the TAILOR RT study, which is a randomized noninferiority clinical trial designed to assess the value of RNI in patients with low-risk N1 disease. Eligible patients had breast-conserving surgery or mastectomy and axillary lymph node dissection with 1 to 3 positive nodes, breast-conserving surgery and sentinel lymph node biopsy with 1 to 2 positive nodes, or mastectomy and sentinel lymph node biopsy with 1 positive node. Additionally, patients had luminal A breast cancers, as approximated by estrogen receptor positive (Allred 6-8/8), progesterone receptor (PR) positive (Allred 6-8/8), human epidermal growth factor receptor 2-negative, and grade 1 to 2 immunohistochemical testing. All patients were prescribed hormonal treatment. The primary endpoint of BCRFI, the time to any breast cancer recurrence or breast cancer-related death, was analyzed using a multivariate competing risks analysis.
The cohort included 1169 women with a median follow-up of 9.2 years. Radiation treatments were not performed in 151 women treated with mastectomy alone, were delivered to the breast only in 133 women, and were delivered locoregionally in 885 women. Patients undergoing RNI were younger (median age: 58 vs 62 years), more likely to have 2 to 3 macroscopic lymph nodes involved, and more often received chemotherapy (all P < .05). The 10-year estimate of BCRFI was 90% without RNI versus 90% with RNI (P = .5). On multivariable analysis, RNI was not a significant predictor of BCRFI (hazard ratio: 1.0; P = .9).
In this retrospective analysis, RNI was not associated with improved BCRFI for women with biologically low-risk N1 breast cancer. We advocate accrual to the ongoing TAILOR RT study.
随机临床试验表明，对未经选择的 N1 期乳腺癌患者进行区域淋巴结照射（RNI）可改善乳腺癌特异性生存。然而，RNI 对生物学低风险 N1 期乳腺癌患者的益处尚不确定。我们进行了一项基于人群的研究，以确定在这一人群中，RNI 是否与改善乳腺癌无复发生存期（BCRFI）相关。
本研究纳入了 2005 年至 2014 年间诊断为 pT1-2 pN1（淋巴结阳性）乳腺癌且年龄在 40 至 79 岁之间的患者。纳入标准是基于 TAILOR RT 研究设计的，该研究是一项旨在评估 RNI 在低危 N1 疾病患者中价值的随机非劣效性临床试验。符合条件的患者行保乳手术或乳房切除术和腋窝淋巴结清扫术，伴 1-3 个阳性淋巴结；行保乳手术和前哨淋巴结活检术，伴 1-2 个阳性淋巴结；或行乳房切除术和前哨淋巴结活检术，伴 1 个阳性淋巴结。此外，患者均为 luminal A 型乳腺癌，即雌激素受体阳性（Allred 6-8/8）、孕激素受体（PR）阳性（Allred 6-8/8）、人表皮生长因子受体 2 阴性、免疫组织化学分级 1-2 级。所有患者均接受了激素治疗。使用多变量竞争风险分析来分析无复发生存期（BCRFI）这一主要终点，即任何乳腺癌复发或乳腺癌相关死亡的时间。
该队列纳入了 1169 例女性患者，中位随访时间为 9.2 年。151 例接受单纯乳房切除术的患者未行放疗，133 例患者仅行乳腺放疗，885 例患者行局部区域放疗。行 RNI 的患者年龄更小（中位年龄：58 岁 vs 62 岁），更有可能有 2-3 个宏观淋巴结受累，且更常接受化疗（均 P<0.05）。无 RNI 的患者 10 年 BCRFI 估计值为 90%，有 RNI 的患者为 90%（P=0.5）。多变量分析显示，RNI 不是 BCRFI 的显著预测因素（风险比：1.0；P=0.9）。
在这项回顾性分析中，RNI 并未改善生物学低风险 N1 期乳腺癌患者的 BCRFI。我们主张继续进行 TAILOR RT 研究。
