Impact of Mastectomy Flap Necrosis on Patient-Reported Quality-of-Life Measures After Nipple-Sparing Mastectomy: A Preliminary Analysis.

BACKGROUND: Mastectomy skin flap necrosis (SFN) is common following nipple-sparing mastectomy (NSM), but studies on its quality-of-life (QOL) impact are limited. We examined patient-reported QOL and satisfaction after NSM with/without SFN utilizing the BREAST-Q patient-reported outcome measure (PROM) survey. PATIENTS AND METHODS: Patients undergoing NSM between April 2018 and July 2021 at our institution were examined; the BREAST-Q PROM was administered preoperatively, and at 6 months and 1 year postoperatively. SFN extent/severity was documented at 2-3 weeks postoperatively; QOL and satisfaction domains were compared between patients with/without SFN. RESULTS: A total of 573 NSMs in 333 patients were included, and 135 breasts in 82 patients developed SFN (24% superficial, 56% partial thickness, 16% full thickness). Patients with SFN reported significantly lower scores in the satisfaction with breasts (p = 0.032) and psychosocial QOL domains (p = 0.009) at 6 months versus those without SFN, with scores returning to baseline at 1 year in both domains. In the "physical well-being-of-the-chest" domain, there was an overall decline in scores among all patients; however, there were no significant differences at any time point between patients with or without SFN. Sexual well-being scores declined for patients with SFN compared with those without at 6 months and also at 1 year, but this did not reach significance (p = 0.13, p = 0.2, respectively). CONCLUSIONS: Patients undergoing NSM who developed SFN reported significantly lower satisfaction and psychosocial well-being scores at 6 months, which returned to baseline by 1 year. Physical well-being of the chest significantly declines after NSM regardless of SFN. Future studies with larger sample sizes and longer follow-up are needed to determine SFN's impact on long-term QOL.

Strategies to avoid mastectomy skin-flap necrosis during nipple-sparing mastectomy.

BACKGROUND: Nipple-sparing mastectomy is associated with a higher risk of mastectomy skin-flap necrosis than conventional skin-sparing mastectomy. There are limited prospective data examining modifiable intraoperative factors that contribute to skin-flap necrosis after nipple-sparing mastectomy. METHODS: Data on consecutive patients undergoing nipple-sparing mastectomy between April 2018 and December 2020 were recorded prospectively. Relevant intraoperative variables were documented by both breast and plastic surgeons at the time of surgery. The presence and extent of nipple and/or skin-flap necrosis was documented at the first postoperative visit. Necrosis treatment and outcome was documented at 8-10 weeks after surgery. The association of clinical and intraoperative variables with nipple and skin-flap necrosis was analysed, and significant variables were included in a multivariable logistic regression analysis with backward selection. RESULTS: Some 299 patients underwent 515 nipple-sparing mastectomies (54.8 per cent (282 of 515) prophylactic, 45.2 per cent therapeutic). Overall, 23.3 per cent of breasts (120 of 515) developed nipple or skin-flap necrosis; 45.8 per cent of these (55 of 120) had nipple necrosis only. Among 120 breasts with necrosis, 22.5 per cent had superficial, 60.8 per cent had partial, and 16.7 per cent had full-thickness necrosis. On multivariable logistic regression analysis, significant modifiable intraoperative predictors of necrosis included sacrificing the second intercostal perforator (P = 0.006), greater tissue expander fill volume (P < 0.001), and non-lateral inframammary fold incision placement (P = 0.003). CONCLUSION: Modifiable intraoperative factors that may decrease the likelihood of necrosis after nipple-sparing mastectomy include incision placement in the lateral inframammary fold, preserving the second intercostal perforating vessel, and minimizing tissue expander fill volume.

Diagnostic performance of image-guided vacuum-assisted breast biopsy after neoadjuvant therapy for breast cancer: prospective pilot study.

BACKGROUND: Image-guided vacuum-assisted breast biopsy (VABB) of the tumour bed, performed after neoadjuvant therapy, is increasingly being used to assess residual cancer and to potentially identify to identify pathological complete response (pCR). In this study, the accuracy of preoperative VABB specimens was assessed and compared with surgical specimens in patients with triple-negative or human epidermal growth factor receptor 2 (HER2)-positive invasive ductal breast cancer after neoadjuvant therapy. As a secondary endpoint, the performance of contrast-enhanced MRI of the breast and PET-CT for response prediction was assessed. METHODS: This single-institution prospective pilot study enrolled patients from April 2018 to April 2021 with a complete response on imaging (iCR) who subsequently underwent VABB before surgery. Those with a pCR at VABB were included in the primary analysis of the accuracy of VABB. The performance of imaging (MRI and PET-CT) was analysed for prediction of a pCR considering both patients with an iCR and those with residual disease at postneoadjuvant therapy imaging. RESULTS: Twenty patients were included in the primary analysis. The median age was 44 (range 35-51) years. At surgery, 18 of 20 patients showed a complete response (accuracy 90 (95 per cent exact c.i. 68 to 99) per cent). Only two patients showed residual ductal intraepithelial neoplasia of grade 2 and 3 respectively. In the secondary analysis, accuracy was similar for MRI and PET-CT (77 versus 78 per cent; P = 0.76). CONCLUSION: VABB in patients with an iCR might be a promising method to select patients for de-escalation of surgical treatment in triple-negative or HER2-positive breast cancer. The present results support such an approach and should inform the design of future trials on de-escalation of surgery.

A Randomized Trial of Robotic Mastectomy Versus Open Surgery in Women With Breast Cancer or BrCA Mutation.

OBJECTIVE: The aim of this study was to compare robotic mastectomy with open classical technique outcomes in breast cancer patients. SUMMARY BACKGROUND DATA: As the use of robotic nipple sparing mastectomy continues to rise, improved understanding of the surgical, oncologic, and quality of life outcomes is imperative for appropriate patient selection as well as to better understand indications, limits, advantages, and dangers. METHODS: In a phase III, open label, single-center, randomized controlled trial involving 80 women with breast cancer (69) or with BRCA mutation (11), we compared the outcome of robotic and open nipple sparing mastectomy. Primary outcomes were surgical complications and quality of life using specific validated questionnaires. Secondary objective included oncologic outcomes. RESULTS: Robotic procedure was 1 hour and 18 minutes longer than open (P < 0.001). No differences in the number or type of complications (P = 0.11) were observed. Breast-Q scores in satisfaction with breasts, psychosocial, physical and sexual well-being were significantly higher after robotic mastectomy versus open procedure. Respect to baseline, physical and sexual well-being domains remained stable after robotic mastectomy, whereas they significantly decreased after open procedure (P < 0.02). The overall Body Image Scale questionnaire score was 20.7 ±â€Š13.8 versus 9.9 ±â€Š5.1 in the robotic versus open groups respectively, P < 0.0001. At median follow-up 28.6months (range 3.7-43.3), no local events were observed. CONCLUSIONS: Complications were similar among groups upholding the robotic technique to be safe. Quality of life was maintained after robotic mastectomy while significantly decrease after open surgery. Early follow-up confirm no premature local failure.ClinicalTrials.gov NCT03440398.

Escalating de-escalation in breast cancer treatment.

Efforts have continually been made to de-escalate treatment for breast cancer, with the goal of balancing oncologic outcomes with complications and patient quality of life. In the early 2000s, two landmark studies firmly established that conservative treatment approaches for breast cancer can be safe and effective. More recently, neoadjuvant chemotherapy has gained momentum as a potential standard of care for breast cancer. An important question has thus arisen: Can neoadjuvant approaches themselves be de-escalated to further minimize adverse treatment effects while maintaining oncological outcomes? In this editorial, we look at the available evidence and assess current trends in treatment de-escalation for women with breast cancer.

Points to Consider Regarding Risk-Reducing Mastectomy in High-, Moderate-, and Low-Penetrance Gene Carriers.

Risk-reducing mastectomy is considered a safe and effective surgical procedure in high-risk individuals with BRCA1/2 germline mutations. Multigene panels identify women with alterations in breast cancer susceptibility genes other than BRCA1/2. International guidelines classify these genes as high-, moderate-, and low-penetrance based on their associated relative risk for breast cancer. Classification of specific genes is not always concordant among guidelines, and the indications for risk-reducing mastectomy are not defined. In this opinion paper, we review some considerations to clarify these controversial points.

Does preoperative MRI accurately stratify early-stage HER2 + breast cancer patients to upfront surgery vs neoadjuvant chemotherapy?

PURPOSE: HER2 +- amplified breast cancer patients derive benefit from treatment with anti-HER2-targeted therapy. Though adjuvant treatment is based on final pathology, decisions regarding neoadjuvant chemotherapy are made in the preoperative setting with imaging playing a key role in staging. We examined the accuracy of pre-operative imaging in determining pathological tumor size  (pT) in patients undergoing upfront surgery. METHODS: Early (cT1-T2N0) HER2 + breast cancer patients who underwent upfront surgery between 2015 and 2016 were identified from a prospective institutional database. We compared data for both clinical and final pathologic stage. Only those who underwent magnetic resonance imaging (MRI), mammography, and ultrasound in the preoperative setting were included in the analysis. Adjuvant treatment regimens were reviewed. RESULTS: We identified 87 cT1-2N0 patients with invasive HER2 + breast cancer who underwent upfront surgery. Median age was 52 years (IQR 43, 58) and median tumor size was 1.1 cm (IQR 0.5, 1.6). Fifteen patients (17%) were upstaged to stage II/III based on final pathology. Thirty-seven patients were T1cN0 on final pathology; 8 were cT1a-bN0 preop and 12 had pT overestimated by MRI by an average of 1.5 cm (> 0.5-1.5 cm). Compared to both mammography and MRI, the imaging modality most predictive of pT was ultrasound (p = 0.000072 ultrasound vs mammography and 0.000042 ultrasound vs MRI). CONCLUSION: For small HER2 + cN0 tumors undergoing upfront surgery, ultrasound was the imaging modality most predictive of pT. MRI overestimated tumor size in approximately 40% of patients. MRI may not accurately discriminate low-volume tumor burden in the breast and carries the potential of overtreatment in the upfront setting.

Tumor-Nipple Distance of ≥ 1 cm Predicts Negative Nipple Pathology After Neoadjuvant Chemotherapy.

BACKGROUND: As neoadjuvant chemotherapy (NAC) for breast cancer has become more widely used, so has nipple-sparing mastectomy. A common criterion for eligibility is a 1 cm tumor-to-nipple distance (TND), but its suitability after NAC is unclear. In this study, we examined factors predictive of negative nipple pathologic status (NS-) in women undergoing total mastectomy after NAC. METHODS: Women with invasive breast cancer treated with NAC and total mastectomy from August 2014 to April 2018 at our institution were retrospectively identified. Following review of pre- and post-NAC magnetic resonance imaging (MRI) and mammograms, the association of clinicopathologic and imaging variables with NS- was examined and the accuracy of 1 cm TND on imaging for predicting NS- was determined. RESULTS: Among 175 women undergoing 179 mastectomies, 74% of tumors were cT1-T2 and 67% were cN+ on pre-NAC staging; 10% (18/179) had invasive or in situ carcinoma in the nipple on final pathology. On multivariable analysis, after adjusting for age, grade, and tumor stage, three factors, namely number of positive nodes, pre-NAC nipple-areolar complex retraction, and decreasing TND, were significant predictors of nipple involvement (p < 0.05). The likelihood of NS- was higher with increasing TND on pre- and post-NAC imaging (p < 0.05). TND ≥ 1 cm predicted NS- in 97% and 95% of breasts on pre- and post-NAC imaging, respectively. CONCLUSIONS: Increasing TND was associated with a higher likelihood of NS-. A TND ≥ 1 cm on pre- or post-NAC imaging is highly predictive of NS- and could be used to determine eligibility for nipple-sparing mastectomy after NAC.

E-cadherin deregulation in breast cancer.

E-cadherin protein (CDH1 gene) integrity is fundamental to the process of epithelial polarization and differentiation. Deregulation of the E-cadherin function plays a crucial role in breast cancer metastases, with worse prognosis and shorter overall survival. In this narrative review, we describe the inactivating mechanisms underlying CDH1 gene activity and its possible translation to clinical practice as a prognostic biomarker and as a potential targeted therapy.

A machine learning model that classifies breast cancer pathologic complete response on MRI post-neoadjuvant chemotherapy.

BACKGROUND: For breast cancer patients undergoing neoadjuvant chemotherapy (NAC), pathologic complete response (pCR; no invasive or in situ) cannot be assessed non-invasively so all patients undergo surgery. The aim of our study was to develop and validate a radiomics classifier that classifies breast cancer pCR post-NAC on MRI prior to surgery. METHODS: This retrospective study included women treated with NAC for breast cancer from 2014 to 2016 with (1) pre- and post-NAC breast MRI and (2) post-NAC surgical pathology report assessing response. Automated radiomics analysis of pre- and post-NAC breast MRI involved image segmentation, radiomics feature extraction, feature pre-filtering, and classifier building through recursive feature elimination random forest (RFE-RF) machine learning. The RFE-RF classifier was trained with nested five-fold cross-validation using (a) radiomics only (model 1) and (b) radiomics and molecular subtype (model 2). Class imbalance was addressed using the synthetic minority oversampling technique. RESULTS: Two hundred seventy-three women with 278 invasive breast cancers were included; the training set consisted of 222 cancers (61 pCR, 161 no-pCR; mean age 51.8 years, SD 11.8), and the independent test set consisted of 56 cancers (13 pCR, 43 no-pCR; mean age 51.3 years, SD 11.8). There was no significant difference in pCR or molecular subtype between the training and test sets. Model 1 achieved a cross-validation AUROC of 0.72 (95% CI 0.64, 0.79) and a similarly accurate (P = 0.1) AUROC of 0.83 (95% CI 0.71, 0.94) in both the training and test sets. Model 2 achieved a cross-validation AUROC of 0.80 (95% CI 0.72, 0.87) and a similar (P = 0.9) AUROC of 0.78 (95% CI 0.62, 0.94) in both the training and test sets. CONCLUSIONS: This study validated a radiomics classifier combining radiomics with molecular subtypes that accurately classifies pCR on MRI post-NAC.

Validation of a Novel Nomogram for Prediction of Local Relapse after Surgery for Invasive Breast Carcinoma.

BACKGROUND: Around 7% of women who undergo breast-conserving surgery (BCS) or mastectomy are at risk of developing ipsilateral breast tumor recurrence (IBTR). When assessing risks that, like that of IBTR, depend on multiple clinicopathological variables, nomograms are the predictive tools of choice. In this study, two independent nomograms were constructed to estimate the individualized risk of IBTR after breast surgery. PATIENTS AND METHODS: In this retrospective study, 18,717 consecutive patients with primary invasive breast cancer were enrolled. The training set used for building the nomograms comprised 15,124 patients (11,627 treated with BCS and 3497 with mastectomy), while the validation set included 3593 women (2565 BCS and 1028 mastectomy). Median follow-up time was 8 years in the training set and 6 years in the validation set. Multivariable Cox proportional hazards regression was used to identify independent factors for IBTR. Two separated nomograms were constructed on multivariate models for BCS and mastectomy. RESULTS: The factors that associated with IBTR after either BCS or mastectomy were identified. The two multivariable models were used to build nomograms for the prediction of IBTR 1 year, 5 years, and 10 years after BCS or after mastectomy. Five-year and 10-year IBTR rates in the BCS training set were equal to 3.50% and 7.00%, respectively, and to 5.39% and 7.94% in the mastectomy training set. The nomograms were subsequently validated with c-index values of 0.77 and 0.69 in the BCS and mastectomy validation sets, respectively. CONCLUSIONS: The nomograms presented in this study provide clinicians and patients with a valuable decision-making tool for choosing between different treatment options for invasive breast cancer.

Increase in Utilization of Nipple-Sparing Mastectomy for Breast Cancer: Indications, Complications, and Oncologic Outcomes.

BACKGROUND: Nipple-sparing mastectomy (NSM) is increasingly performed for invasive breast cancer. Growing evidence supporting the oncologic safety of NSM has led to its widespread use and broadened indications. In this study, we examine the indications, complications, and long-term outcomes of therapeutic NSM. METHODS: From 2003 to 2016, women undergoing NSM for invasive cancer or ductal carcinoma in situ (DCIS) were identified from a prospectively maintained database. Patient and disease characteristics were compared by procedure year, while complications were compared by procedure year using generalized mixed-effects models accounting for a random surgeon effect. Overall survival and time to recurrence were examined. RESULTS: Of the 467 therapeutic NSMs, 337 (72%) were invasive cancer, 126 (27%) were DCIS, and 4 (1%) were phyllodes tumors. Median age was 45 years (range 24-75) and median follow-up among survivors was 39.4 months. Three hundred and fifty-seven (76.4%) cases were performed in 2011 or after. When comparing NSMs performed before and after 2011, there was a significant increase in NSMs performed for invasive tumors (58% vs. 77%; p < 0.001). There was no difference in family history, genetic mutations, smoking status, neoadjuvant chemotherapy, prior radiation, nodal involvement, or tumor subtype. Twenty-one (4.5%) nipple excisions were performed, of which 14 were performed for cancer at the nipple margin. Forty-four breasts (9.4%) had complications that required re-operation. Fifteen patients had locoregional recurrence or distant metastasis. CONCLUSIONS: NSM use for invasive carcinoma has doubled at our institution since 2011, while postoperative complications and recurrence rates remain low. Our experience supports the selective use of NSM in the malignant setting with careful patient selection.

Update on the Feasibility and Progress on Robotic Breast Surgery.

BACKGROUND: Robotic nipple-sparing mastectomy (RNSM) may allow for more precise anatomic dissection and improved cosmetic outcomes over conventional open nipple-sparing mastectomy; however, data regarding the feasibility and safety of the procedure are limited. OBJECTIVE: The aim of this study was to present and discuss perioperative surgical outcomes and early oncologic follow-up data on consecutive patients undergoing RNSM from June 2014 to January 2019. METHODS: Patients underwent RNSM and immediate robotic breast reconstruction through an axillary incision at a single institution. Perioperative data, complications at 3 months postoperatively, pathological data, and adjuvant therapies were recorded. Local recurrence-free, disease-free, and overall survival were analyzed. RESULTS: Overall, 73 women underwent 94 RNSM procedures. Indications were invasive breast cancer in 39 patients, ductal carcinoma in situ in 17 patients, and BRCA mutation in 17 patients. Mean surgery time was 3 h and 32 min. One-step reconstruction with implant occurred in 89.4% of procedures. The rate of complications requiring reoperation was 4.3%, and the rate of flap or nipple necrosis was 1.1%. Median follow-up was 19 months (range 3.1-44.8). No local recurrences occurred. Overall survival at 12, 24, or 60 months was 98% (95% confidence interval 86-100%). CONCLUSION: We observed a low complication rate in 94 consecutive RNSM procedures, demonstrating the procedure is technically feasible and safe. We found no early local failures at 19 months follow-up. Long-term follow-up is needed to confirm oncologic safety. Future clinical trials to study the advantages and disadvantages of RNSM are warranted.

A Comparison of Patient-Reported Outcomes After Nipple-Sparing Mastectomy and Conventional Mastectomy with Reconstruction.

INTRODUCTION: Nipple-sparing mastectomy (NSM) is increasingly used for breast cancer risk reduction and treatment. Prior small studies with variable control for baseline characteristics suggest superior satisfaction with NSM. The purpose of this study was to compare patient satisfaction following NSM and total mastectomy (TM) utilizing the BREAST-Q patient-reported outcome measure in a well-characterized patient population. METHODS: Patients at a single institution undergoing NSM or TM with immediate tissue expander/implant reconstruction who completed a follow-up BREAST-Q from 2007 to 2017 were identified by retrospective review of a prospective database. Baseline characteristics were compared, and linear mixed models were used to analyze associations with BREAST-Q scores over time. RESULTS: Of 1866 eligible patients, 219 (12%) underwent NSM, and 1647 (88%) underwent TM. Median time from baseline to BREAST-Q was 658 days. Patients with NSM were younger, more likely to be white, and had lower BMI. They more often had prophylactic surgery, bilateral mastectomies, lower-stage disease, and less often received chemotherapy/radiation than patients with TM. On multivariable analysis, after controlling for relevant clinical variables, there was no difference in satisfaction with breasts or satisfaction with outcome overall between NSM and TM patients. Psychosocial well-being and sexual well-being were significantly higher in the NSM group. After additionally controlling for preoperative BREAST-Q score in a subset of patients (72 NSM; 443 TM), only psychosocial well-being remained significantly higher in NSM patients. CONCLUSIONS: Patient-reported outcomes should be discussed with women weighing the risks and benefits of NSM to provide a better understanding of expected quality of life.

Axillary Dissection and Nodal Irradiation Can Be Avoided for Most Node-positive Z0011-eligible Breast Cancers: A Prospective Validation Study of 793 Patients.

OBJECTIVE: To determine rates of axillary dissection (ALND) and nodal recurrence in patients eligible for ACOSOG Z0011. BACKGROUND: Z0011 demonstrated that patients with cT1-2N0 breast cancers and 1 to 2 involved sentinel lymph nodes (SLNs) having breast-conserving therapy had no difference in locoregional recurrence or survival after SLN biopsy alone or ALND. The generalizability of the results and importance of nodal radiotherapy (RT) is unclear. METHODS: Patients eligible for Z0011 had SLN biopsy alone. Prospectively defined indications for ALND were metastases in ≥3 SLNs or gross extracapsular extension. Axillary imaging was not routine. SLN and ALND groups and radiation fields were compared with chi-square and t tests. Cumulative incidence of recurrences was estimated with competing risk analysis. RESULTS: From August 2010 to December 2016, 793 patients met Z0011 eligibility criteria and had SLN metastases. Among them, 130 (16%) had ALND; ALND did not vary based on age, estrogen receptor, progesterone receptor, or HER2 status. Five-year event-free survival after SLN alone was 93% with no isolated axillary recurrences. Cumulative 5-year rates of breast + nodal and nodal + distant recurrence were each 0.7%. In 484 SLN-only patients with known RT fields (103 prone, 280 supine tangent, 101 breast + nodes) and follow-up ≥12 months, the 5-year cumulative nodal recurrence rate was 1% and did not differ significantly by RT fields. CONCLUSIONS: We confirm that even without preoperative axillary imaging or routine use of nodal RT, ALND can be avoided in a large majority of Z0011-eligible patients with excellent regional control. This approach has the potential to spare substantial numbers of women the morbidity of ALND.

First international consensus conference on standardization of oncoplastic breast conserving surgery.

PURPOSE: To obtain consensus recommendations for the standardization of oncoplastic breast conserving surgery (OPS) from an international panel of experts in breast surgery including delegates from the German, Austrian and Swiss societies of senology. METHODS: A total of 52 questions were addressed by electronic voting. The panel's recommendations were put into context with current evidence and the report was circled in an iterative open email process until consensus was obtained. RESULTS: The panelists considered OPS safe and effective for improving aesthetic outcomes and broadening the indication for breast conserving surgery (BCS) towards larger tumors. A slim majority believed that OPS reduces the rate of positive margins; however, there was consensus that OPS is associated with an increased risk of complications compared to conventional BCS. The panel strongly endorsed patient-reported outcomes measurement, and recommended selected scales of the Breast-Q™-Breast Conserving Therapy Module for that purpose. The Clough bi-level classification was recommended for standard use in clinical practice for indicating, planning and performing OPS, and the Hoffmann classification for surgical reports and billing purposes. Mastopexy and reduction mammoplasty were the only two recognized OPS procedure categories supported by a majority of the panel. Finally, the experts unanimously supported the statement that every OPS procedure should be tailored to each individual patient. CONCLUSIONS: When implemented into clinical practice, the panel recommendations may improve safety and effectiveness of OPS. The attendees agreed that there is a need for prospective multicenter studies to optimize patient selection and for standardized criteria to qualify and accredit OPS training centers.

Multicentric Cancer Detected at Breast MR Imaging and Not at Mammography: Important or Not?

PURPOSE: To review the magnetic resonance (MR) imaging and pathologic features of multicentric cancer detected only at MR imaging and to evaluate its potential biologic value. MATERIALS AND METHODS: This retrospective study was institutional review board approved and HIPAA compliant; informed consent was waived. A review of records from 2001 to 2011 yielded 2021 patients with newly diagnosed breast cancer who underwent biopsy after preoperative MR imaging, 285 (14%) of whom had additional cancer detected at MR imaging that was occult at mammography. In 73 patients (3.6%), MR imaging identified 87 cancers in different quadrants than the known index cancer, constituting the basis of this report. In 62 of 73 patients (85%; 95% confidence interval [CI]: 75, 92), one additional cancer was found, and in 11 of 73 (15%; 95% CI: 8, 25), multiple additional cancers were found. A χ(2) test with adjustment for multiple lesions was used to examine whether MR imaging and pathologic features differ between the index lesion and additional multicentric lesions seen only at MR imaging. RESULTS: Known index cancers were more likely to be invasive than MR imaging-detected multicentric cancers (88% vs 76%, P = .023). Ductal carcinoma in situ (21 of 87 lesions [24%]; 95% CI: 15, 36) represented a minority of additional MR imaging-detected multicentric cancers. Overall, the size of MR imaging-detected multicentric invasive cancers (median, 0.6 cm; range, 0.1-6.3 cm) was smaller than that of the index cancer (median, 1.2 cm; range, 0.05-7.0 cm; P = .023), although 17 of 73 (23%) (95% CI: 14, 35) patients had larger MR imaging-detected multicentric cancers than the known index lesion, and 18 of 73 (25%) (95% CI: 15, 36) had MR imaging-detected multicentric cancers larger than 1 cm. MR imaging-detected multicentric cancers and index cancers differed in histologic characteristics, invasiveness, and grade in 27 of 73 (37%) patients (95% CI: 26, 49). In four of 73 (5%) patients (95% CI: 2, 13), MR imaging-detected multicentric cancers were potentially more biologically relevant because of the presence of unsuspected invasion or a higher grade. CONCLUSION: Multicentric cancer detected only at MR imaging was invasive in 66 of 87 patients (76%), larger than 1 cm in 18 of 73 patients (25%), larger than the known index cancer in 17 of 73 patients (23%), and more biologically important in four of 73 women (5%). An unsuspected additional multicentric cancer seen only at MR imaging is likely clinically relevant disease.

How Often Does Neoadjuvant Chemotherapy Avoid Axillary Dissection in Patients With Histologically Confirmed Nodal Metastases? Results of a Prospective Study.

BACKGROUND: In breast cancer patients with nodal metastases at presentation, false-negative rates lower than 10 % have been demonstrated for sentinel node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) when three or more negative sentinel nodes (SLNs) are retrieved. However, the frequency with which axillary dissection (ALND) can be avoided is uncertain. METHODS: Among 534 prospectively identified consecutive patients with clinical stages 2 and 3 cancer receiving NAC from November 2013 to November 2015, all biopsy-proven node-positive (N+) cases were identified. Patients clinically node-negative after NAC were eligible for SLNB. The indications for ALND were failed mapping, fewer than three SLNs retrieved, and positive SLNs. RESULTS: Of 288 N+ patients, 195 completed surgery, with 132 (68 %) of these patients eligible for SLNB. The median age was 50 years. Of these patients, 73 (55 %) were estrogen receptor-positive (ER+), 21 (16 %) were ER- and human epidermal growth factor receptor-2-positive (HER2+), and 38 (29 %) were triple-negative. In four cases, SLNB was deferred intraoperatively. Among 128 SLNB attempts, three or more SLNs were retrieved in 110 cases (86 %), one or two SLNs were retrieved in 15 cases (12 %), and failed mapping occurred in three cases (2 %). In 66 cases, ALND was indicated: 54 (82 %) for positive SLNs, 9 (14 %) for fewer than three negative SLNs, and 3 (4 %) for failed mapping. Persistent disease was found in 17 % of the patients with fewer than three negative SLNs retrieved. Of the 128 SLNB cases, 62 (48 %) had SLNB alone with three or more SLNs retrieved. Among 195 N+ patients who completed surgery, nodal pathologic complete response (pCR) was achieved for 49 %, with rates ranging from 21 % for ER+/HER2- to 97 % for ER-/HER2+ cases, and was significantly more common than breast pCR in ER+/HER2- and triple-negative cases. CONCLUSIONS: Nearly 70 % of the N+ patients were eligible for SLNB after NAC. For 48 %, ALND was avoided, supporting the role of NAC in reducing the need for ALND among patients presenting with nodal metastases.