Sacituzumab govitecan (SG), an antibody-drug conjugate directed at Trop-2, has been approved for metastatic triple-negative breast cancer (mTNBC) and more recently for hormone receptor-positive/HER2-negative metastatic breast cancer (mHRPBC). Although its efficacy has been proven in controlled clinical trials, real-world insights—particularly those including both molecular subtypes—are still limited. This multicenter, retrospective investigation assessed real-world clinical effectiveness, tolerability, and prognostic determinants of SG therapy among patients diagnosed with mTNBC or mHRPBC. Sixty-eight individuals who received SG treatment between 2022 and 2025 at several oncology institutions across Turkey were included. Eligibility required at least one prior chemotherapy regimen for mTNBC and two prior lines, plus CDK4/6 inhibitors with hormone therapy, for mHRPBC. Outcomes assessed were progression-free survival (PFS), overall survival (OS), and objective response rate (ORR). Potential prognostic factors were examined through univariate and multivariate models. Adverse events (AEs) were documented and classified per NCI-CTCAE v5.0. Of the participants, 35 (51.5%) had mTNBC and 33 (48.5%) had mHRPBC. The median PFS was 6.1 months, and the median OS was 12.5 months, with no significant variation between groups. The overall response rate was 52.9%, with 10.3% achieving complete remission. Poorer outcomes for PFS and OS were independently linked to higher ECOG performance scores and hepatic metastases. Prior exposure to immunotherapy did not appear to lessen SG’s effect. The treatment was largely well tolerated, most frequently causing alopecia, anemia, neutropenia, and diarrhea, with only 2.9% discontinuing due to toxicity. SG demonstrated comparable outcomes and manageable safety profiles across mTNBC and mHRPBC subgroups. Although PFS and OS findings were in line with those from clinical trials, the lack of a comparator arm restricts causal interpretation. Crucially, this work provides one of the earliest real-world datasets describing SG use in mHRPBC, underlining its clinical promise beyond trial conditions. These findings support SG as an effective therapeutic alternative for heavily pretreated patients and highlight the need for further prospective and biomarker-based studies.
