Before treatment, the patients in the study group underwent NGS detection of ctDNA and formulated treatment plan according to the test results: 1) those with ESR1 mutation and who did not use fulvestrant before, preferred fulvestrant; 2) those with abnormal activation of PI3K/Akt/mTOR pathway signal, preferred mTOR inhibitor combined with endocrine therapy; 3) those with HER-2 sensitive point mutation, preferred anti-HER-2 therapy combined with endocrine therapy; 4) PDGFR mutation, preferential use of PDGFR inhibitors combined with endocrine therapy; 5) no significant gene mutation, making endocrine therapy plan according to the actual clinical situation. After 2 months of endocrine therapy, all patients underwent NGS detection of ctDNA, and the efficacy was evaluated according to RECIST v1.1 standard. If the efficacy evaluation is effective, continue the current treatment and re-evaluate the efficacy every two months; if the efficacy evaluation is ineffective (progress), then withdraw from this study. The vital signs, blood routine, liver and kidney functions and imaging examinations were examined at least every two months in the patients in the study group, and the curative effect was evaluated according to RECIST v1.1 standard.
