Treatment Intermittent Periods Based on ctDNA-MRD（Circulating Tumor DNA-minimal Residual Disease） Status in Advanced HER2-Positive Breast Cancer

"Definition and Essence: ctDNA MRD involves detecting DNA fragments released by tumor cells into the bloodstream through highly sensitive techniques to determine the status of minimal residual disease in cancer patients.~Detection Methods: Technologies such as digital PCR and next-generation sequencing (NGS) are employed to achieve precise detection of low-frequency ctDNA mutations.~Clinical Significance: It is utilized for evaluating the prognosis of cancer patients and providing crucial evidence for the formulation of personalized treatment plans."