Multicentric Breast Cancer Research Articles

Comparison of Contrast-Enhanced Spectral Mammography and Contrast-Enhanced MRI in Screening Multifocal and Multicentric Lesions in Breast Cancer Patients.

Objectives We aimed to determine the difference between contrast-enhanced spectral mammography (CESM) and contrast-enhanced magnetic resonance imaging (CE-MRI) in detecting multifocal and multicentric breast cancer (MMBC). Methods: This study was conducted among breast cancer patients between July 1, 2017, and May 30, 2021. The sensitivity, specificity, and accuracy of CESM and CE-MRI in the diagnosis of MMBC were evaluated with pathological results as the gold standard. Results A total of 188 lesions were detected in 54 patients with MMBC, including 177 breast cancer and 11 benign lesions. Based on CESM and CE-MRI, 4 false-positive cases and 3 false-negative cases and 7 false-positive cases and 1 false-negative case, respectively, were found. The accuracy of CESM was higher than that of MRI (96.3% vs 95.7%), and the specificity was higher than that of MRI (63.6% vs 36.4%). There were no significant differences in the sensitivity, specificity, and accuracy for the detection of MMBC between CESM and CE-MRI (p = 0.500; p = 0.250; p = 0.792). Conclusion CESM is an effective method for the detection of MMBC, which is consistent with the sensitivity and accuracy of CE-MRI.

Baseline cardio-oncologic risk assessment in breast cancer women and occurrence of cardiovascular events: The HFA/ICOS risk tool in real-world practice

Backgroundthe European Society of Cardiology Heart Failure Association (HFA) together with the International Cardio-Oncology Society (ICOS) proposed charts for baseline CV risk assessment of cancer patients scheduled to receive anthracyclines and anti-human epidermal growth factor receptor-2 (HER2) agents. MethodsWe investigated HFA/ICOS risk stratification, prescriptions of cardioactive drugs, and occurrence of CV events in a multicentric breast cancer (BC) cohort from 3 Italian Outpatient Cardio-Oncology Clinics. Results373 BC patients who underwent a baseline Cardio-Oncologic evaluation were included, of whom 202 scheduled to receive anthracyclines and 171 anti-HER2. Mean age was 60 ± 12 years and 49% of BC patients had ≥2 CV risk factors. In the anthracyclines group, 51% were at low-risk, 43% at medium-risk and 6% at high-risk; while in the anti-HER2 group, 27% patients were at low-risk, 58% at medium-risk and 15% at high-risk. In both groups, a medium-to-high risk was associated with use of cardioactive therapies (p < 0.0001). There were no LVD events in anthracycline recipients, and 16 LVD among anti-HER2 patients. A medium-to-high risk was not associated with LVD occurrence (p = 0.17). ConclusionsPatients with medium-to-high HFA/ICOS risk were more likely to receive cardioactive therapies, possibly explaining the lack of association of risk categories with LVD occurrence.

Oncoplastic Breast-Conserving Surgery for Synchronous Multicentric and Multifocal Tumors: Is It Oncologically Safe? A Retrospective Matched-Cohort Analysis

BackgroundOncoplastic surgery is a well-established approach that combines breast-conserving treatment for breast cancer and plastic surgery techniques. Although this approach already has been described for multicentric and multifocal tumors, no long-term oncologic follow-up evaluation and no comparison with patients undergoing mastectomy have been published. This study aimed to evaluate whether oncoplastic surgery is a safe and reliable treatment for managing invasive primary multicentric and multifocal breast cancer.MethodsThe study compared a consecutive series of 100 patients with multicentric or multifocal tumors who had undergone oncoplastic surgery (study group) with 100 patients who had multicentric or multifocal tumors and had undergone mastectomy (control group) during a prolonged period. The end points evaluated were disease-free survival (DFS), overall survival (OS), cumulative incidence of local recurrence (CI-L), regional recurrence (CI-R), and distant recurrence (CI-D), all measured from the date of surgery.ResultsThe OS and DFS were similar between the two groups. The incidence of local events was higher in the oncoplastic group, whereas the incidence of regional events was slightly higher in the mastectomy group. These differences were not statistically significant. The cumulative incidence of distant events was similar between the two groups.ConclusionsTo the authors’ knowledge, the current study provides the best available evidence suggesting that the oncoplastic approach is a safe and reliable treatment for managing invasive multifocal and multicentric breast cancers.

Efficacy of mammography and contrast‑enhanced spectral mammography in women with multifocal and multicentric breast cancer.

Efficacy of mammography and contrast‑enhanced spectral mammography in women with multifocal and multicentric breast cancer.

Extreme Oncoplasty: Breast Conservation in Patients with Large, Multifocal, and Multicentric Breast Cancer.

IntroductionExtreme Oncoplastic Breast Conservation Surgery (EOBCS) is offered in selected patients with multifocal or multicentric breast cancer (MFMC). Recent evidence has suggested that EOBCS may be a valuable resource for patients with MFMC who may avoid the risk associated with mastectomy in favour of the benefits of breast conservation without risking their oncological outcomes. Our study examined the practice of EOBCS in two regional breast units in Glasgow, United Kingdom.Materials and MethodsA prospectively collected database of 50 patients treated with EOBC in two breast units in Glasgow between 2007 and 2018 were evaluated, and clinical outcomes were observed.ResultsFifty patients (median age 55) underwent EOBCS, of which 43 (86%) had invasive disease. Median tumour size was 55mm (50–90) and multifocal disease was identified in 22 (44%) patients. Nine patients (18%) were found to have positive margins and underwent a second procedure, with 6 (12%) proceeding to mastectomy. Five-year disease free survival rate was 91.5%, while cancer-specific survival was 95.7%.ConclusionEOBCS is oncologically safe in short-term follow-up. Large scale studies are required to confirm these preliminary results, in order to offer EOBCS as a valid option to patients with advanced or multifocal breast cancer.

Abstract PS18-22: Association of molecular biomarkers heterogeneity and treatment pattern, disease outcomes in multifocal or multicentric breast cancer patients

Abstract Background: To evaluate the rates of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 heterogeneity in multifocal or multicentric breast cancer (MMBC) and its association with treatment pattern and disease outcomes.Methods: MMBC patients with ER, PR, HER2, and Ki67 results for each tumor focus were retrospectively analyzed. Patients with concordant ER, PR, HER2, and Ki67 status among all invasive tumor foci were categorized into the Homo group, while the rest were defined as the Hetero group. Chi-square or Fisher test were performed to compare the treatment options between the Hetero and Homo groups. Disease-free survival (DFS) and overall survival (OS) rates were estimated from Kaplan-Meier curves and compared between two groups.Results: A total of 330 patients were included. Concordance rates of ER, PR, HER2, Ki67, and molecular subtype were 97.0%, 93.9%, 96.5%, 91.2%, and 88.2%, respectively (all P values &amp;lt; 0.001). There were 53 (16.1%) and 287 (83.9%) patients classified into the Hetero and Homo groups. Adjuvant endocrine therapy was more frequently assigned for patients in the Hetero group than in the Homo group (84.9% vs. 71.7%, P = 0.046). There was no difference in terms of adjuvant anti-HER2 therapy (28.3% vs. 19.6%, P = 0.196) and chemotherapy (69.9% vs. 69.8%, P = 0.987) usage between two groups. At a median follow-up of 36 months, DFS rates were 81.2% for the Hetero group and 96.5% for the Homo group (HR = 2.81, 95% CI: 1.00-7.88, P = 0.041). The estimated 3-year OS rates for these two groups were 95.8% and 99.5%, respectively (HR = 4.31, 95% CI: 0.83-22.46, P = 0.059).Conclusion: Heterogeneity of ER, PR, HER2, or Ki67 was present in 16.1% patients with MMBC. Biomarkers heterogeneity influenced adjuvant endocrine therapy usage and was associated with worse disease outcomes, indicating further clinical evaluation. Citation Format: Shuai Li, Jiayi Wu, Ou Huang, Jianrong He, Li Zhu, Weiguo Chen, Yafen Li, Xiaosong Chen, Kunwei Shen. Association of molecular biomarkers heterogeneity and treatment pattern, disease outcomes in multifocal or multicentric breast cancer patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS18-22.

Concordance Between 21-Gene Recurrence Scores in Multifocal or Multicentric Breast Carcinomas Differs by Age and Histologic Subtype.

Among patients with multifocal or multicentric (MF/MC) breast cancer (BC) of similar morphology, concordance in Oncotype DX recurrence scores (RS) between tumors has been reported to be 87%. The effect of age and variation in histologic subtypes on RS concordance according to TAILORx criteria is unknown. We identified patients with MF/MC, estrogen receptor-positive, HER2-negative, node-negative BC with two or more RS results treated at our institution from 2009 to 2018. Patients were analyzed by age group (≤ 50 and > 50years). Low- and high-risk cut-offs were RS ≤ 25 and > 25 for age > 50years, and RS ≤ 20 and > 20 for age ≤ 50years. RS concordance was defined as no change in management based on RS variation between lesions. Overall, 120 patients with MF/MC BC were identified-82 (68.3%) aged > 50years and 38 (31.7%) aged ≤ 50years. Patients aged ≤ 50years had higher mean RS for both multifocal (20 vs. 14; p = 0.006) and multicentric (17 vs. 13; p = 0.003) tumors and more frequently had high-risk tumors (p < 0.0001). Among patients aged > 50years, 95.1% had RS concordance between tumors (same subtype, 98.2%; variable subtype, 88.9%; p = 0.1). Among patients aged ≤ 50years, RS concordance was 81.6%. Among patients with MF/MC BC, RS concordance was high, particularly in those aged > 50years with tumors of the same histologic subtype. RS testing of one focus may be sufficiently prognostic and predictive in patients aged > 50years, regardless of subtype concordance. Testing of individual foci should be considered in patients aged ≤ 50years due to a higher likelihood of RS discordance.

The full breast ultrasonography usefulness in the diagnosis of a bicentric breast cancer – An anatomical imaging approach correlated with the pathological findings: A case report

Introduction: The classification of multiple, simultaneous, ipsilateral breast cancer after localization in arbitrarily delimited quadrants, according to BI-RADS criteria, is in disagreement with pathological and cytogenetic investigations and with the evolution of the disease. This classification is related to the non-anatomical examination in two standard mammographic projections, including tomosynthesis, and to the non-anatomical orthogonal scanning in the classical ultrasonography and magnetic resonance imaging of the breasts. Case Report: We illustrate a case of a 69-year-old woman with multicentric breast cancer detected and characterized by a non-invasive technique of diagnosis, based on the triad: anatomical ductal radial and antiradial breast ultrasound, Doppler study and strain sonoelastography, briefly named the full breast ultrasonography. Conclusion: The complete technique of ultrasonography has the advantages of high availability, low costs, standardization of scanning and reporting, and especially a detailed imaging illustration of the breast anatomical normal and abnormal structures correlated with the pathological findings.

Multicentric breast cancer comprising of three different histopathological types: a case report

Multicentric breast cancer comprising of three different histopathological types: a case report

Quality of life in patients with multicentric breast cancer

One of the main issues in the treatment of multicentric breast cancer (BC) is to choose the type of surgery (paying attention to the tendency to reduce the volume of surgical interventions). Many studies have demonstrated an adverse effect of this form of BC on long‑term survival outcomes (increased risk of recurrence, decreased overall survival rates, etc.). However, none of the studies examined the effect of surgery extent on the quality of life of these patients.Objective. To assess the effect of the surgery type on the quality of life of patients with multicentric BC.Materials and methods. 190 patients were included in the study. The median follow‑up was 72 (7–116) months. Age ranged from 27 to 76 years. The majority of patients (150 women, 78.9 %) had luminal HER2‑negative tumors, while «aggressive» (HER2‑overexpressing, triple negative) subtypes were detected in 40 (21.1 %) of them. 134 patients underwent radical mastectomy (40 of which also had immediate breast reconstruction), 56 received breast‑conserving surgery. Statistically significant differences were not observed among stages III and I–II BC (p = 0.125). The quality of life was assessed with the use of EORTC QLQ-C30 and EORTC QLQ-BR23 scales at ≥ 12 months after performing surgical treatment.Results. The quality of life was assessed depending on the type of surgical intervention. The patients after breastconserving surgery and immediate breast reconstruction demonstrated a significant advantage, primarily in the general perception of one's own health (p &lt; 0.05) and emotional status (p &lt; 0.05). Also, there were no significant differences in quality of life between the groups of patients after breast‑ conserving surgery and immediate breast reconstruction.Conclusion. Due to the increase in the life expectancy of breast cancer patients, the issues of maintaining a high quality of life are becoming increasingly important. From this point of view, performing breast‑ conserving and reconstructive surgeries is preferable for patients with multicentric BC.

P072: Prospective randomised controlled trial evaluation safety of breast conserving surgery in multicentric/multifocal breast cancer

Introduction: Until recently breast conserving surgery (BCS) was not considered a safer option in multifocal/ multicentric breast cancers as recurrence rates were thought to be high. The objective of the study is to show that breast conserving surgery is comparable to mastectomy in term of 5 years disease free (DFS) and overall survival (OS).

Personalized neoadjuvant strategy in luminal A breast cancer to increase breast conserving surgery (BCS) rate [PLATO study

TPS603 Background: The most important and well established benefit of neoadjuvant therapy for breast cancer patients is increased breast conservation rate. However, in ER-positive and HER-2 negative breast cancer, the response to neoadjuvant chemotherapy (NCT) is not as good as other subtype of breast cancer, such as HER-2 or triple-negative breast cancer. In addition, with the advancement of multi-gene assay tools for this subtype, adjuvant chemotherapy is not needed at all in significant proportion of this subtype. Through a selective neoadjuvant therapy, either chemotherapy or endocrine therapy using histopathologic markers and 70-gene assay (Mammaprint. Agendia inc.), we hypothesize that we could increase the breast conservation rate in ER-positive and HER-2 negative breast cancer. Methods: This study is a non-randomized, phase II, prospective study. The main inclusion criteria is women with stage I-IIIA, ER-positive and HER-2 negative breast cancer that tumor size is measurable. BCS is not feasible considering the tumor size, location, and patient's breast size. Two surgeons in each institution will judge the feasibility of BCS. Main exclusion criteria is diffuse malignant microcalcification or multicentric breast cancer. The conversion rate from BCS-ineligible to BCS-eligible with NCT was 35.8% in ER-positive and HER-2 negative breast cancer in our previous study. We assumed that with the study regimen, the rate will be increased to 50.8% (15% increase). Given these estimates, under 10% type II error rate and 90% power, 122 patients in total will be enrolled from nine tertiary hospitals in Korea. All the patients initially will be tested with Mammaprint assay. When the Mammaprint result is high risk, the patients will receive NCT. When the Mammaprint result is low risk, the patients will receive neoadjuvant endocrine therapy. Postmenopausal women receive letrozole 2.5mg per day for 16 weeks. Premenopausal women receive leuprorelin every 4 weeks with letrozole for 16 weeks. Period of neoadjuvant endocrine therapy can be prolonged maximum 24 weeks by physician’s decision. The primary endpoint is conversion rate from BCS-ineligible to BCS-eligible of more than 50%. The secondary endpoint is actual breast conservation rate, pathologic complete response, clinical response rate, and disease-free survival. Clinical trial information: NCT03900637 .

The role of digital mammography, scintimammography with &lt;sup&gt;99m &lt;/sup&gt;Tc-methoxyisobutylisonitrile (MIBI) and ultrasound in the diagnosis of multicentric breast cancer

Background. The development of effective methods for diagnosing multicentric breast cancer patients (BC) is of great clinical importance, because it determines the tactics of surgical and radiation treatment. The aim of study: to compare diagnostic accuracy of scintimammography (SMG), digital mammography (MMG) and ultrasound (US) in the diagnosis of multicentric BC. Materials and methods . 410 women with histologically confirmed BC were included in this analysis. SMG was performed with dual detector SPECT unit Forte (Philips, Netherlands). Mammographic digital images were obtained on Senographe DS unit (GE Healthcare, USA). In 319 of 410 evaluated women we were able to determine results of preoperative US with high-frequency (7—18 MHz), high resolution linear array transducer. The pathological report was used as the gold standard. Multicentric BC was defined as 2 or more distinct invasive tumors occupying more than one quadrant. Detection of additional grouped calcifications of malignant type occupying a small portion of breast tissue (more than 15 pieces per 1 sq. cm) was considered as another mammographic sign of multicentric BC. Results. According to histopathological examinations multicentric BC was diagnosed in 51 of 410patients. SMG was more effective than MMG in detecting multicentric BC: sensitivity — 84.3 % vs 54.9 % (p <0.001), specificity — 98 % vs 95.8 % (p = 0.02), accuracy — 96.3 % vs 90.7 % (p = 0.04), positive and negative predictive values — 86 % vs 65.1 % (p = 0.004) and 97.8 % vs 93.7 % (p = 0.01), respectively. Histologically multicentric BC was revealed in 44 of 319 women that had US of the breasts. Sensitivity, specificity, accuracy, positive and negative predictive values for US were 52.3 %, 94.5 %, 88.7 %, 60.5 % and 92.5 %, respectively. SMG significantly (p <0.001) outperformed US for all diagnostic characteristics. Combination of MMG and SMG characterized by increased sensitivity (94.1 %), 94.2 % specificity, 94.1 % accuracy and positive predictive value of only 69,6 %. Conclusions. SMG is significantly more sensitive (84.3 %) than MMG (54.9 %) and US (52.3 %) in detection of multicentric BC. High (86 %) positive predictive value of SMG advocates it as a tool for surgery and radiotherapy planning.

Precision surgery for multifocal multicentric breast cancer in the genomic era

: Controversy exists with respect to appropriateness of breast conservation treatment (BCT) for multifocal multicentric breast cancer (MFMCBC). There is potential for the role of genomics to inform the extent of surgical therapy which should be undertaken for breast cancer. This review was conducted to clarify contemporary selection criteria for surgical therapy in patients with MFMCBC and to identify areas for future research. Contemporary efforts to tailor treatment using molecular technology have thus far centred on medical therapy. The use of genomics to direct surgical therapy has yet to gain comparable significance. At present, surgical treatment for MFMCBC is selected based on clinic-pathologic characteristics. Data suggests that genomics may predict response to neoadjuvant therapy for downstaging and margin status requirements to allow de-escalation of surgical treatment. There is room for future research relating to biomarkers and how genomic technology may impact the management of MFMCBC for individualized surgical therapy.

Multicentric breast cancer with heterogeneous histopathology: a multidisciplinary review.

Multiple synchronous (multifocal or multicentric) ipsilateral breast cancers with heterogeneous histopathology area rare clinical occurrence, however, their incidence is increasing due to the use of MRI for breast cancer screening and staging. Some studies have demonstrated poorer clinical outcomes for this pattern of breast cancer, but there is no evidence to guide clinical practice. In this multidisciplinary review, we reflect on pathology and molecular characteristics, imaging findings, surgical management including conservation and reconstructive options and approach to the axilla, and the role of chemotherapy and radiotherapy. Multidisciplinary discussions appeardecisive in planning an appropriate surgical choice and defining the correct systemic treatmenttailored to each clinical condition.

Multifocal breast cancers are more prevalent in BRCA2 versus BRCA1 mutation carriers.

Multifocal (MF)/multicentric (MC) breast cancer is generally considered to be where two or more breast tumours are present within the same breast, and is seen in ~10% of breast cancer cases. This study investigates the prevalence of multifocality/multicentricity in a cohort of BRCA1/2 mutation carriers with breast cancer from Northern Ireland via cross‐sectional analysis. Data from 211 women with BRCA1/2 mutations (BRCA1‐91, BRCA2‐120) and breast cancer were collected including age, tumour focality, size, type, grade and receptor profile. The prevalence of multifocality/multicentricity within this group was 25% but, within subgroups, prevalence amongst BRCA2 carriers was more than double that of BRCA1 carriers (p = 0.001). Women affected by MF/MC tumours had proportionately higher oestrogen receptor positivity (p = 0.001) and lower triple negativity (p = 0.004). These observations are likely to be driven by the higher BRCA2 mutation prevalence observed within this cohort. The odds of a BRCA2 carrier developing MF/MC cancer were almost four‐fold higher than a BRCA1 carrier (odds ratio: 3.71, CI: 1.77–7.78, p = 0.001). These findings were subsequently validated in a second, large independent cohort of patients with BRCA‐associated breast cancers from a UK‐wide multicentre study. This confirmed a significantly higher prevalence of MF/MC tumours amongst BRCA2 mutation carriers compared with BRCA1 mutation carriers. This has important implications for clinicians involved in the treatment of BRCA2‐associated breast cancer, both in the diagnostic process, in ensuring that tumour focality is adequately assessed to facilitate treatment decision‐making, and for breast surgeons, particularly if breast conserving surgery is being considered as a treatment option for these patients.

99mTc-MIBI scintimammography and digital mammography in the diagnosis of multicentric breast cancer.

To compare diagnostic accuracy of scintimammography (SMG) and digital mammography (DS) in the diagnosis of multicentric breast cancer. Three hundred and sixty seven women with histologically confirmed breast cancer were included in this analysis. All patients were candidates for conservative breast surgery and had cT1-3N0-1 stage of disease. Scintimammography was performed in prone position 5-10min after intravenous injection of 740MBq of technetium-99m-methoxy-isobtyl-isonitrile (99mTc-MIBI) with acquisition time of 10min for every lateral and anterior projection. Digital mammography was done in all women according to a standard clinical protocol. Final diagnosis was established by histopathology. Multicentric breast cancer was defined as 2 or more distinct invasive tumors located in more than one quadrant or additional lesions from the primary tumor of more than 4cm in size. According to histopathological examinations multicentric breast cancer was diagnosed in 47 of 367 (12.8%) patients. Scintimammography was more effective than mammography in detecting multicentric breast cancer: sensitivity: 83.0% vs 40.4% (P<0.001), specificity: 97.8% vs 95.3% (P=0.4), accuracy: 95.9% vs 88.3% (P<0.001), positive and negative predictive values: 84.8% vs 55.9% (P=0.004) and 97.5% vs 91.6% (P<0.001), respectively. Combination of DM and SMG was characterized by increased sensitivity (93.6%), worse specificity (93.4%), accuracy (93.4%) and worse predictive value (67.7%) as compared to only SMG. Scintimammography was significantly much better by all statistical parameters than DM in the detection of multicentric breast cancer. High positive predictive value of scintimammography (84.8%) advocates it as a tool for surgery and radiotherapy planning.

Multifocal and multicentric breast cancer, is it time to think again?

Multifocal multicentric breast cancer has traditionally been considered a contraindication to breast conserving surgery because of concerns regarding locoregional control and risk of disease recurrence. However, the evidence supporting this practice is limited. Increasingly, many breast surgeons are advocating breast conservation in selected cases. This short narrative review summarises current evidence on the role of surgery in multifocal multicentric breast cancer and shows that when technically feasible the option of breast conservation is oncologically safe.

Does the classification system for multifocal and multicentric breast cancers alter breast conservation rates?

Does the classification system for multifocal and multicentric breast cancers alter breast conservation rates?

Local Control of Breast Conservation Therapy versus Mastectomy in Multifocal or Multicentric Breast Cancer: A Systematic Review and Meta-Analysis

Objective: Breast conservation therapy (BCT) for female patients with multifocal or multicentric (MF/MC) breast cancer remains controversial. The purpose of the present meta-analysis was to explore whether BCT was feasible for female patients with MF/MC breast cancer and to compare the results of treatment with those of female patients with unifocal breast cancer who underwent BCT and female patients with MF/MC breast cancer who underwent mastectomy. Methods: Online databases, including PubMed and Embase, were independently searched from inception to January 2018 and reviewed by two authors. The present meta-analysis compared local relapse (LR) of BCT versus mastectomy for patients with MF/MC breast cancer and LR of patients with unifocal breast cancer versus patients with MF/MC breast cancer who underwent BCT. Ten studies comprising 19,272 patients were included. Results: The cumulative incidence of LR was 5.6% (65/1,163) for MF/MC disease treated with BCT, 4.2% (750/17,656) for unifocal disease treated with BCT, and 2.0% (9/453) for MF/MC disease treated with mastectomy. Thus, the cumulative incidence of LR for MF/MC patients treated with BCT was significantly higher than for mastectomy (p < 0.001). However, the forest plot analysis showed no significant differences in LR between BCT and mastectomy procedures (OR = 1.22, 95% CI = 0.49–3.00, p = 0.67, I² = 0%). Compared with the unifocal group treated with BCT, BCT for MF/MC breast cancer showed a significant difference in LR (OR = 2.25, 95% CI = 1.48–3.42, p = 0.0001, I² = 0%). Conclusion: The LR of BCT for patients with MF/MC breast cancer was higher than that of BCT for patients with unifocal breast cancer. However, no significant difference was found in the incidence of LR between the BCT group and the mastectomy group in patients with MF/MC breast cancer.