Lymph node metastasis is more likely in early-stage breast cancer with lower tumor-infiltrating lymphocyte (TIL) density. Therefore, we investigated the correlation between TILs and lymph node metastasis in cT1 breast cancer patients undergoing surgery and the usefulness of TILs in predicting sentinel lymph node metastasis (SLNM) in cT1N0M0 breast cancer. We investigated 332 breast cancer patients who underwent surgery as the first-line treatment after preoperative diagnosis of cT1. A positive diagnosis of SLNM as an indication for axillary clearance was defined as macrometastasis in the sentinel lymph node (SLN) (macrometastasis: tumor diameter > 2 mm). Semi-quantitative evaluation of lymphocytes infiltrating the peritumoral stroma as TILs in primary tumor biopsy specimens prior to treatment was conducted. For SLN biopsy (SLNB), a median of 2 (range, 1–8) SLNs were pathologically evaluated. Sixty cases (19.4%) of SLNM (macrometastasis: 46, micrometastasis: 16) were observed. Metastasis was significantly greater in breast cancers with tumor diameter > 10 mm than in those with diameter ≤ 10 mm (p = 0.016). Metastasis was significantly associated with lymphatic invasion (p < 0.001). These two clinicopathological factors correlated with SLNM even in patients diagnosed with cN0 (tumor size; p = 0.017, lymphatic invasion; p = 0.002). Multivariate analysis for SLNM predictors revealed lymphatic invasion (p = 0.008, odds ratio [OR] = 2.522) and TILs (p < 0.001, OR = 0.137) as independent factors. Our results suggest a correlation between lymph node metastasis and tumor immune-microenvironment in cT1 breast cancer. TIL density may be a predictor of SLNM in breast cancer without lymph node metastasis on preoperative imaging.

中文翻译：

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T1乳腺癌中肿瘤浸润淋巴细胞对淋巴结转移的预测。

早期乳腺癌的肿瘤浸润淋巴细胞（TIL）密度较低，更可能发生淋巴结转移。因此，我们调查了接受手术的cT1乳腺癌患者的TIL与淋巴结转移之间的相关性，以及TIL在预测cT1N0M0乳腺癌的前哨淋巴结转移（SLNM）中的作用。我们对332例术前诊断为cT1的乳腺癌患者进行了手术作为一线治疗。SLNM阳性诊断为腋窝清除的指征被定义为前哨淋巴结（SLN）的大转移（Macstastastasis：肿瘤直径> 2 mm）。在治疗前，对原发肿瘤活检标本中浸润瘤周围基质的淋巴细胞进行TIL的半定量评估。对于SLN活检（SLNB），病理评估了2个SLN（范围为1-8）的中位数。观察到SLNM 60例（19.4％）（巨乳转移：46，微转移：16）。肿瘤直径> 10 mm的乳腺癌的转移明显大于直径≤10 mm的乳腺癌（p = 0.016）。转移与淋巴管浸润显着相关（p <0.001）。即使在被诊断为cN0的患者中，这两个临床病理因素也与SLNM相关（肿瘤大小； p = 0.017，淋巴管浸润； p = 0.002）。对SLNM预测因子的多变量分析显示淋巴管浸润（p = 0.008，优势比[OR] = 2.522）和TIL（p <0.001，OR = 0.137）是独立因素。我们的结果表明，cT1乳腺癌的淋巴结转移与肿瘤免疫微环境之间存在相关性。