Background: The new antibody-drug conjugated directed to HER2, Trastuzumab-Deruxtecan (T-DXd), has shown the benefit of progression-free survival and overall survival in metastatic breast cancer (mBC) patients after progression to ≥1 HER2 targeted therapies. Interstitial lung disease (ILD) and cardiotoxicity are the most significant and concerning toxicities related to T-DXd. We performed a systematic review and meta-analysis to assess the incidence and severity of those adverse events (AE) in mBC patients treated with T-DXd. Methods: We comprehensively searched Pubmed, Cochrane, and Scopus databases for randomized clinical trials (RCT) and observational cohort studies, including mBC patients with HER2-low or -positive expression who have received at least one dose of T-DXd. The DESTINY-Breast02 study was also included after its presentation at the SABCS 2022. The statistical analysis was performed using R software, and the results are presented as pooled analysis in forest plots. Results: We included nine studies: three phase III RCTs, three phase II and two phase I non-RCTs, and one retrospective cohort comprising 1,443 patients with a mean follow-up of 14.9 months. The median age of our population ranged from 53 to 59 years. Most were non-Asian (40.5%) and presented with hormone-receptor positive mBC (66.8%). In a pooled analysis, the incidence of ILD was 13.0% (179 patients; 95%CI 11.0 to 13.0). Patients enrolled in phase III clinical trials had an ILD rate of 12.0%, while the observational cohort reported a numerically higher rate of 18.0%. Most ILD cases, 84.9% (152 patients), were mild (grade 1 or 2). Grade 3 or 4 AE were reported in 13 patients (7,3%), and grade 5 in 14 patients (7,8%). Decreased left ventricular ejection fraction (LVEF) was seen in 3.6% (95%CI 3.0 – 5.0%), and most patients were asymptomatic. Eleven patients developed prolonged QT interval, and four had left ventricular dysfunction and cardiac failure. Conclusions: Our meta-analysis reinforces the importance of close vigilance for pulmonary and cardiac toxicities in mBC patients on treatment with T-DXd. Early detection and management by a multidisciplinary team following the most recent guidelines may improve the patient outcomes.