Real-world Study of Sacituzumab Govitecan Monotherapy or Combination Therapy in Recurrent or Metastatic HER2-negative Breast Cancer

Other illness

• Known allergy to sacituzumab govitecan (SG) or any of its components.
• Diagnosis of other malignancies within the past 5 years
• Presence of acute or chronic infections, or coexisting serious diseases (such as decompensated heart, lung, liver, or renal failure), assessed by investigators as incompatible with tolerating the study treatment.
• Mental illness or psychiatric disorders leading to poor compliance, inability to cooperate with the study, or inability to describe treatment responses.
• Modification of the treatment regimen after SG administration for reasons other than disease progression.

Age

• History of other malignancies, except the following:
  • Cured basal cell carcinoma, squamous cell skin carcinoma, cervical in situ carcinoma, or papillary thyroid carcinoma.
  • A second primary cancer that has been completely cured with a tumor-free interval of ≥5 years.
  • Other malignancies where the primary tumor source of metastatic foci has been clearly identified by investigators.

Other

• Pregnant or lactating women.
• Current participation in other interventional clinical studies.
• Any other circumstances deemed by investigators as likely to interfere with study evaluation, affect subject safety, or render the patient unsuitable for enrollment.

• Age and Gender Male or female aged 18 years or older.
• Pathological Diagnosis and Classification Criteria (Must Meet Either Cohort Condition) 2.1 Triple-Negative Breast Cancer (TNBC) Cohort
  • Histologically/cytologically confirmed triple-negative breast cancer (TNBC) by pre-SG biopsy/pathology report, with the following criteria:
  • HER2-negative: Immunohistochemistry (IHC) score of 0 or 1+; if IHC score is 2+, HER2 negativity must be confirmed by fluorescence in situ hybridization (FISH).
  • Estrogen and progesterone receptor-negative: \<1% of cells express hormone receptors as determined by IHC.
  • Presence of locally advanced, recurrent, or metastatic disease (locally advanced disease must be confirmed by investigators as ineligible for curative resection).
  • 2.2 Hormone Receptor-Positive/HER2-Negative Breast Cancer (HR+/HER2- BC) Cohort
  • Histologically/cytologically confirmed HR+/HER2- breast cancer by pre-SG biopsy/pathology report, with the following criteria:
  • HER2-negative: Immunohistochemistry (IHC) score of 0 or 1+; if IHC score is 2+, HER2 negativity must be confirmed by fluorescence in situ hybridization (FISH).
  • HR-positive: Hormone receptor positivity (HR, including ER or PR status) is defined as ≥1% cell expression by IHC.
  • Presence of locally advanced, recurrent, or metastatic disease (locally advanced disease must be confirmed by investigators as ineligible for curative resection).
• Treatment Protocol Requirements Planned to receive SG monotherapy or combination therapy.
• Other Enrollment Criteria Willing to participate in the study, sign the informed consent form, and demonstrate good compliance.