Prognostic Significance and Predictive Value of Circulating Tumor Cells in Invasive Lobular Breast Carcinoma-An Exploratory Analysis of the STIC CTC Trial.

The STIC CTC phase III trial (N = 778, hormone receptor-positive HER2- metastatic breast cancer) showed that ≥5 CTC/7.5 mL before treatment predicted greater benefit from first-line chemotherapy over endocrine therapy for progression-free (PFS) and overall survival(OS).

STIC CTC III期试验（N=778，激素受体阳性HER2-转移性乳腺癌）显示，在治疗前≥5 CTC/7.5 mL预示着一线化疗相较于内分泌治疗在无进展生存（PFS）和总生存（OS）方面有更大的益处。

This exploratory analysis examines these results by histologic subtype, comparing invasive lobular carcinoma (ILC) and carcinoma of no special type (NST).

这项探索性分析通过组织学亚型来检查这些结果，比较了浸润性小叶癌(ILC)和非特殊类型癌(NST)。

experimental_design

Baseline CTC count (CellSearch) and its impact on PFS and OS were compared between ILC (N = 159) and NST (N = 571).

在ILC（N=159）和NST（N=571）之间比较了基线循环肿瘤细胞(CTC)计数（CellSearch）及其对无进展生存期(PFS)和总生存(OS)的影响。

The survival benefit of chemotherapy in patients with a high CTC count was then re-evaluated separately for each subtype.

然后，对每个亚型的患者分别重新评估了化疗在高CTC计数患者中的生存益处。

Results

Before treatment, ILC had significantly higher CTC counts than NST [median, 10 (Q1 = 2, Q3 = 40) vs. 1 (Q1 = 0, Q3 = 7)]. ≥5 CTC/7.5 mL were detected in 64% (95% confidence interval, 56-71) of patients with ILC and 31% (95% confidence interval, 28-35) of patients with NST, correlating with shorter PFS and OS in both.

治疗前，ILC的CTC计数显著高于NST[中位数，10（Q1 = 2，Q3 = 40）vs. 1（Q1 = 0，Q3 = 7）]。

However, patients with ILC and ≥5 CTC/7.5 mL saw no significant benefit from CTC-informed chemotherapy [PFS: HR, 0.91 (0.55-1.52); OS: HR, 0.83 (0.46-1.52)].

然而，具有浸润性导管癌（ILC）和≥5个CTC/7.5 mL的患者在接受CTC指导的化疗后，并未显示出显著的益处[无进展生存期（PFS）：风险比（HR），0.91（95%置信区间（CI），0.55-1.52）；总生存（OS）：HR，0.83（95% CI，0.46-1.52）].

In contrast, patients with NST and ≥5 CTC/7.5 mL had markedly improved outcomes with chemotherapy [PFS: HR, 0.54 (0.37-0.81); OS: HR, 0.37 (0.21-0.66)].

相比之下，具有非特殊类型（NST）和≥5个CTC/7.5 mL的患者在接受化疗后，预后明显改善[无进展生存期（PFS）：风险比（HR），0.54（95%置信区间（CI），0.37-0.81）；总生存（OS）：HR，0.37（95% CI，0.21-0.66）].

Conclusions

ILC sheds more CTC than NST, likely owing to underlying biological differences.

ILC比NST释放更多的循环肿瘤细胞（CTC），这很可能是由于潜在的生物学差异所致。

Although the ≥5 CTC/7.5-mL threshold remained a valid prognostic marker for both, it was predictive of chemotherapy benefit in NST but not in ILC.

尽管≥5 CTC/7.5-mL的阈值对于两者都是一个有效的预后标志物，但它能预测浸润性导管癌（NST）化疗的益处，而对于浸润性小叶癌（ILC）则不能。

These findings highlight differences in biomarker utility between ILC and NST, affecting both threshold relevance and treatment response.

这些发现强调了浸润性小叶癌(ILC)和非特殊类型浸润性癌(NST)之间生物标志物效用的差异，影响了阈值的相关性和治疗反应。