Evaluation of a Genetic Risk Score for Lung Metastasis and Prognosis in Breast Cancer

The goal of this observational study is to validate the predictive ability of a six-gene risk score model for lung metastasis in patients with early-stage breast cancer. The main questions it aims to answer are: Does the gene risk score accurately identify patients at high risk of developing lung metastases? Does it predict lung metastasis-free survival and overall survival in these patients? How does its performance compare with traditional clinical indicators (such as TNM stage, molecular subtype, and Ki-67) across different breast cancer subtypes? Participants will be women aged 70 years or younger with newly diagnosed, non-metastatic early-stage breast cancer. They will receive standard treatment according to routine clinical practice. A single tumor tissue sample (from biopsy or surgery) will be collected for testing the expression of six specific genes, and a risk score will be calculated to classify patients into high-risk or low-risk groups. All participants will be followed for up to 120 months to monitor lung metastasis occurrence and survival outcomes. In addition, the study will explore differences in immune microenvironment characteristics between the two risk groups using a subset of tumor samples.