Multicentric and Multifocal Breast Tumors—Narrative Literature Review

Background: Multifocal (MF) and multicentric (MC) breast cancers, defined by the presence of multiple synchronous tumor foci within the same breast, present important diagnostic, therapeutic, and prognostic challenges. Historically considered a contraindication for breast-conserving therapy (BCT), advances in imaging, surgical techniques, and adjuvant therapy have reshaped management strategies. Methods: A narrative literature review was conducted through PubMed, Web of Science, and Scopus, prioritizing ISI-indexed articles published within the last 10–15 years. More than 55 relevant studies, including systematic reviews, meta-analyses, and large cohorts, were analyzed to evaluate epidemiology, pathological features, imaging modalities, treatment outcomes, and prognosis of MF/MC breast cancers. Results: The reported incidence of MF/MC breast cancers ranges from 10% to 24%, increasing when MRI or whole-organ pathology is applied. MRI can detect otherwise occult additional foci in up to 30% of patients, improving staging accuracy but raising concerns of overdiagnosis. MF/MC presentation is strongly associated with lobular histology, younger age at diagnosis, and higher rates of axillary involvement—nodal positivity is observed in up to 45% of MF/MC cases versus 28% in unifocal tumors. Pathological analyses demonstrate frequent clonal origin of MF lesions, whereas MC lesions may represent independent primaries, occasionally with receptor heterogeneity that alters systemic therapy selection. From a prognostic perspective, older series suggested shorter breast cancer-specific survival (e.g., median 154 vs. 204 months for MF/MC vs. unifocal disease), and higher local recurrence with BCT. However, contemporary analyses, including a 2022 meta-analysis of 15,703 patients, demonstrated no significant difference in overall or disease-free survival once adjusted for tumor size and nodal status. Local recurrence remains slightly higher with BCT in MF/MC (5.6% vs. 4.2%), but outcomes are equivalent to mastectomy when radiotherapy is appropriately delivered. Five-year survival in early-stage MF/MC exceeds 90% with guideline-concordant multimodal therapy. Conclusions: MF/MC breast cancers represent a biologically heterogeneous entity. Optimal outcomes rely on precise imaging, complete excision, tailored systemic therapy, and multidisciplinary management, with increasing acceptance of breast conservation in selected patients.