Introduction

Neoadjuvant systemic therapy (NAST) is vital in the management of HER2-positive (HER2+) breast cancer. Nevertheless, the indications for NAST in tumors <2 cm remain controversial.

Method

A total of 7961 patients were screened from the Surveillance, Epidemiology, and End Result database. Independent prognostic factors were identified using multivariate Cox analysis. Subgroup analyses and Kaplan–Meier analyses were used to simulate whether NAST would provide a survival benefit with different high-risk characteristics. Nomograms were constructed, and an internal validation cohort was employed.

Results

Of the 7961 included patients, 1137 (14.3%) underwent NAST. In the total population, NAST was associated with poorer overall survival (OS) and breast cancer-specific survival (BCSS) (OS: P = 0.00093; BCSS: P  < 0.0001). Multivariate Cox analysis confirmed that NAST markedly affected the prognosis of enrolled patients. Besides, a direct association between T, N, age, subtype, and prognosis was observed. Subgroup analyses yielded in these three subgroups, T1c, hormone receptor-negative, and 61–69 years of age, NAST and AST had comparable OS, while NAST possessed worse BCSS. Notably, even in the N3, we still did not observe any additional benefit of NAST. The calculated C-index of 0.72 and 0.73 confirmed the predictability of the nomograms. The AUCs exhibit consistency in the training and validation cohorts.

Conclusion

Our findings suggest that NAST does not provide additional benefit to patients with T1 HER2+ breast cancer, even in the presence of lymph node metastasis, T1c, or hormone receptor negativity. This study facilitates the implementation of individualized management strategies.

中文翻译：

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新辅助全身治疗能否为 T1 HER2+ 乳腺癌患者提供额外益处：基于不同高风险特征的亚组分析

介绍

新辅助全身治疗 (NAST) 对于 HER2 阳性 (HER2+) 乳腺癌的治疗至关重要。然而，NAST 在<2 cm 肿瘤中的适应症仍存在争议。

方法

从监测、流行病学和最终结果数据库中总共筛查了 7961 名患者。使用多变量 Cox 分析确定独立的预后因素。亚组分析和 Kaplan-Meier 分析用于模拟 NAST 是否会在不同的高风险特征下提供生存获益。构建了列线图，并采用了内部验证队列。

结果

在 7961 名患者中，1137 名 (14.3%) 接受了 NAST。在总人群中，NAST 与较差的总生存期 (OS) 和乳腺癌特异性生存期 (BCSS) 相关（OS：P  = 0.00093；BCSS：P   < 0.0001）。多变量 Cox 分析证实 NAST 显着影响入组患者的预后。此外，还观察到 T、N、年龄、亚型和预后之间存在直接关联。亚组分析显示，在这三个亚组（T1c、激素受体阴性和 61-69 岁）中，NAST 和 AST 的 OS 相当，而 NAST 的 BCSS 较差。值得注意的是，即使在 N3 中，我们仍然没有观察到 NAST 的任何额外好处。计算出的 C 指数为 0.72 和 0.73，证实了列线图的可预测性。 AUC 在训练和验证队列中表现出一致性。

结论

我们的研究结果表明，NAST 不会为 T1 HER2+ 乳腺癌患者提供额外的益处，即使存在淋巴结转移、T1c 或激素受体阴性。这项研究有助于实施个性化管理策略。