低风险早期乳腺癌术后能否不化疗
人类表皮生长因子受体HER2阳性乳腺癌大约占全部乳腺癌的五分之一。根据APT研究，每周紫杉醇＋曲妥珠单抗治疗肿瘤≤3厘米且淋巴结阴性的HER2阳性早期乳腺癌患者，7年无浸润病变生存率为93%。不过，APT研究为单组研究，并非随机对照试验，对于肿瘤≤2厘米且淋巴结阴性的HER2阳性早期乳腺癌，目前尚不明确抗HER2单药治疗与抗HER2联合化疗的临床结局是否相似。
前情提要
2021年10月16日，施普林格自然旗下《乳腺癌研究与治疗》在线发表美国凯斯西储大学医学院、克利夫兰医学中心、赛德曼癌症中心的大数据分析报告，对肿瘤≤2厘米且淋巴结阴性的HER2阳性早期乳腺癌术后曲妥珠单抗±化疗进行了比较。
该研究利用美国外科医师学会全国癌症数据库，将2004～2017年初始诊断为病理T1N0M0期HER2阳性乳腺癌的2万3281例术后曲妥珠单抗辅助治疗患者分为两组：
曲妥珠单抗单药治疗：1013例（4.35%）
曲妥珠单抗联合化疗：2万2268例（96.65%）
由于两组患者的复发风险分布显著不平衡，复发风险较低的患者通常选择曲妥珠单抗单药治疗，复发风险较高的患者通常选择曲妥珠单抗联合化疗，故按3∶1的比例进行倾向评分匹配，以平衡患者选择偏倚，随后对两组患者的5年总生存率进行比较。
结果，根据倾向评分匹配，筛选出曲妥珠单抗联合化疗患者1995例和曲妥珠单抗单药治疗患者666例。
匹配后，曲妥珠单抗联合化疗与曲妥珠单抗单药治疗相比，5年总生存率：94.1%比90.6%（P=0.041）。
因此，该大数据回顾研究结果表明，对于肿瘤≤2厘米且淋巴结阴性的HER2阳性早期乳腺癌术后患者，虽然曲妥珠单抗联合化疗与曲妥珠单抗单药治疗相比，5年总生存率高3.5个百分点，但是曲妥珠单抗单药治疗的5年总生存率高于90%，故对有细胞毒性化疗禁忌证或完全拒绝术后辅助化疗的特定患者，术后曲妥珠单抗单药辅助治疗似乎也是合理的选择。
Breast Cancer Res Treat. 2021 Oct 16. Online ahead of print.
Adjuvant trastuzumab with or without chemotherapy in stage 1 pT1N0 HER2+ breast cancer: a National Cancer Database analysis.
Cao L, Shenk R, Stabellini N, Miller ME, Towe CW, Montero AJ.
University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA; University Hospitals Research in Surgical Outcomes and Effectiveness, Cleveland, OH, USA; Case Western Reserve University School of Medicine, Cleveland, OH, USA; University Hospitals Seidman Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
PURPOSE: Approximately 20% of all breast cancers (BC) are HER2 amplified. In the APT trial, weekly paclitaxel/trastuzumab in node negative HER2+ BC with tumors<3 cm was associated with a 7-year invasive disease-free survival of 93%. However, this was in the context of a non-randomized trial, and for pT1N0 HER2+ BC it remains unclear whether HER2 monotherapy would provide similar clinical outcomes to chemo-HER2 therapy. We hypothesized that adjuvant chemo-HER2 therapy would be associated with a modestly improved overall survival compared to HER2 monotherapy in patients with tumors<2 cm.
METHODS: In the National Cancer Database (2004-2017), patients with a primary diagnosis of pT1N0M0 HER2+ BC, were separated into two groups: (i) HER2 monotherapy, i.e., trastuzumab, and (ii) chemo-HER2 therapy. A 3:1 propensity match was performed to balance patient selection bias between the two different cohorts. Long-term overall survival (OS) was compared between both groups.
RESULTS: A total of 23,281 patients met the criteria. 22,268 (96.7%) received chemo-HER2 therapy and 1013 (4.4%) received HER2 monotherapy. Propensity match identified 1995 patients who received chemo-HER2 therapy, and 666 who received HER2 monotherapy. After matching, adjuvant chemo-HER2 therapy was associated with a modest survival advantage over HER2 monotherapy (5-year OS 94.1% vs. 90.6%, P=0.041).
CONCLUSIONS: Even though there is a modest OS advantage favoring adjuvant chemo-HER2 therapy in patients with pT1N0 HER2+ BC, HER2 monotherapy was associated with 5-year OS>90%. Therefore, in select patients who have contraindications for cytotoxic chemotherapy, or decline adjuvant chemotherapy altogether, adjuvant trastuzumab monotherapy appears to be a reasonable alternative.
KEYWORDS: Breast cancer, Immunotherapy, Chemotherapy, HER2 positive, HER2 breast, NCDB
PMID: 34655345
DOI: 10.1007/s10549-021-06411-4