Omission of Axillary Dissection Following Nodal Downstaging With Neoadjuvant Chemotherapy

Importance

Data on oncological outcomes after omission of axillary lymph node dissection (ALND) in patients with breast cancer that downstages from node positive to negative with neoadjuvant chemotherapy are sparse. Additionally, the best axillary surgical staging technique in this scenario is unknown.

Objective

To investigate oncological outcomes after sentinel lymph node biopsy (SLNB) with dual-tracer mapping or targeted axillary dissection (TAD), which combines SLNB with localization and retrieval of the clipped lymph node.

Design, Setting, and Participants

In this multicenter retrospective cohort study that was conducted at 25 centers in 11 countries, 1144 patients with consecutive stage II to III biopsy-proven node-positive breast cancer were included between April 2013 and December 2020. The cumulative incidence rates of axillary, locoregional, and any invasive (locoregional or distant) recurrence were determined by competing risk analysis.

Exposure

Omission of ALND after SLNB or TAD.

Main Outcomes and Measures

The primary end points were the 3-year and 5-year rates of any axillary recurrence. Secondary end points included locoregional recurrence, any invasive (locoregional and distant) recurrence, and the number of lymph nodes removed.

Results

A total of 1144 patients (median [IQR] age, 50 [41-59] years; 78 [6.8%] Asian, 105 [9.2%] Black, 102 [8.9%] Hispanic, and 816 [71.0%] White individuals; 666 SLNB [58.2%] and 478 TAD [41.8%]) were included. A total of 1060 patients (93%) had N1 disease, 619 (54%) had ERBB2 (formerly HER2)-positive illness, and 758 (66%) had a breast pathologic complete response. TAD patients were more likely to receive nodal radiation therapy (85% vs 78%; P = .01). The clipped node was successfully retrieved in 97% of TAD cases and 86% of SLNB cases (without localization). The mean (SD) number of sentinel lymph nodes retrieved was 3 (2) vs 4 (2) (P < .001), and the mean (SD) number of total lymph nodes removed was 3.95 (1.97) vs 4.44 (2.04) (P < .001) in the TAD and SLNB groups, respectively. The 5-year rates of any axillary, locoregional, and any invasive recurrence in the entire cohort were 1.0% (95% CI, 0.49%-2.0%), 2.7% (95% CI, 1.6%-4.1%), and 10% (95% CI, 8.3%-13%), respectively. The 3-year cumulative incidence of axillary recurrence did not differ between TAD and SLNB (0.5% vs 0.8%; P = .55).

Conclusions and Relevance

The results of this cohort study showed that axillary recurrence was rare in this setting and was not significantly lower after TAD vs SLNB. These results support omission of ALND in this population.

Use of natural language understanding to facilitate surgical de-escalation of axillary staging in patients with breast cancer

Natural language understanding (NLU) may be particularly well-equipped for enhanced data capture from the electronic health record (EHR) given its examination of both content- and context-driven extraction. We developed and applied a NLU model to examine rates of pathological node positivity (pN+) and rates of lymphedema to determine if omission of routine axillary staging could be extended to younger patients with ER+/cN0 disease. We found that rates of pN+ and arm lymphedema were similar between patients 55-69yo and ≥70yo, with rates of lymphedema exceeding rates of pN+ for clinical stage T1c and smaller disease. Data from our NLU model suggest that omission of SLNB might be extended beyond Choosing Wisely recommendations, limited to those over 70 years old, to all postmenopausal women with early-stage ER+/cN0 disease. These data support the recently-reported SOUND trial results and provide additional granularity to facilitate surgical de-escalation.

Patient-Reported Outcomes of Omission of Breast Surgery Following Neoadjuvant Systemic Therapy: A Nonrandomized Clinical Trial

Importance

Patients should have an active role in decisions about pursuing or forgoing specific therapies in treatment de-escalation trials.

Objective

To evaluate longitudinal patient-reported outcomes (PROs) encompassing decisional comfort and health-related quality of life (HRQOL) among patients who elected to enroll in a clinical trial evaluating radiotherapy alone, without breast surgery, for invasive breast cancers with exceptional response to neoadjuvant systemic therapy (NST).

Design, Setting, and Participants

Prospective, single-group, phase 2 clinical trial at 7 US medical centers. Women aged 40 years or older with invasive cT1-2 N0-1 M0 triple-negative or human epidermal growth factor receptor 2 (ERBB2)-positive breast cancer with no pathologic evidence of residual disease following standard NST enrolled from March 6, 2017, to November 9, 2021. Validated PRO measures were administered at baseline and 6, 12, and 36 months post-radiotherapy. Data were analyzed from January to February 2023.

Interventions

PRO measures included the Decision Regret Scale (DRS), Functional Assessment of Cancer Therapy-Lymphedema (FACT-B+4), and Breast Cancer Treatment Outcomes Scale (BCTOS).

Main Outcomes and Measures

Changes in PRO measure scores and subscores over time.

Results

Among 31 patients, the median (IQR) age was 61 (56-66) years, 26 (84%) were White, and 26 (84%) were non-Hispanic. A total of 15 (48%) had triple-negative disease and 16 (52%) had ERBB2-positive disease. Decisional comfort was high at baseline (median [IQR] DRS score 10 [0-25] on a 0-100 scale, with higher scores indicating higher decisional regret) and significantly increased over time (median [IQR] DRS score at 36 months, 0 [0-20]; P < .001). HRQOL was relatively high at baseline (median [IQR] FACT-B composite score 121 [111-134] on a 0-148 scale, with higher scores indicating higher HRQOL) and significantly increased over time (median [IQR] FACT-B score at 36 months, 128 [116-137]; P = .04). Perceived differences between the affected breast and contralateral breast were minimal at baseline (median [IQR] BCTOS score 1.05 [1.00-1.23] on a 1-4 scale, with higher scores indicating greater differences) and increased significantly over time (median [IQR] BCTOS score at 36 months, 1.36 [1.18-1.64]; P < .001). At 36 months postradiotherapy, the cosmetic subscore was 0.45 points higher than baseline (95% CI, 0.16-0.74; P = .001), whereas function, pain, and edema subscores were not significantly different than baseline.

Conclusions and Relevance

In this nonrandomized phase 2 clinical trial, analysis of PROs demonstrated an overall positive experience for trial participants, with longitudinal improvements in decisional comfort and overall HRQOL over time and minimal lasting adverse effects of therapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02945579.

Single-institution outcomes after excision of benign phyllodes tumors: low recurrence risk even with positive margins

PURPOSE

Benign phyllodes tumors (BPT) are rare breast neoplasms with clinical behavior that poses low recurrence risk. Guidelines regarding appropriate margins recommend surgical excision to negative margins, sometimes requiring re-excision surgery. Contemporary experience suggests that re-excision in the face of positive margins may not be needed.

METHODS

This is a retrospective review of a single-institution experience with BPT from 2010 to 2019 with 102 patients. Demographics, outcomes and follow-up were analyzed.

RESULTS

The median age was 37 years. 95% had a pre-operative biopsy and only 6% were confirmed BPT before surgery.56% had positive margins and were more likely to be younger and have a pre-operative diagnosis of fibroadenoma. The median follow-up was 33 months. Between the positive and negative margin groups, recurrence rates were not significantly different (p = 0.87).

CONCLUSION

Positive margins on excision of BPT poses a low recurrence risk and re-excision surgery is not necessary.

Exploring Characteristics of Academic General Surgery Residency Applicants: A Group Concept-Mapping Approach

OBJECTIVE

Holistic review, which emphasizes qualitative attributes over objective measures, has been proposed as a method for selecting candidates for surgical residency in order to improve diversity in graduate medical education, and, ultimately, the field of surgery. This study seeks to articulate desirable traits of applicants as a first-step in standardizing the holistic review process.

DESIGN

Using Group Concept Mapping, a web-based mixed-methods participatory research methodology, residency selection committee members were asked to 1) list desirable characteristics of applicants, 2) group these into categories, 3) rate their importance to academic/clinical success on a 5-point Likert scale (1 = not at all important, 5 = extremely important), and 4) rate the degree to which each characteristic is feasible to assess on a 3-point Likert scale (1 = not at all feasible, 3 = very feasible). Grouped characteristics submitted to hierarchical cluster analysis depicted committee's consensus about desirable qualities/criteria for applicants. Bivariate scatter-plots and pattern-matching graphics demonstrated which of these criteria were most important and reliably assessed.

SETTING

A single academic general surgery residency training program in Western Pennsylvania.

PARTICIPANTS

Members of the selection committee for the UPMC General Surgery Residency program who had participated in at least 1 prior cycle of applicant selection.

RESULTS

Desirable characteristics of highly qualified applicants into an academic general surgery residency were clustered into domains of 1) scholarly work and research, 2) grades/formal assessments, 3) program fit, 4) behavioral assets, and 5) aspiration. Behavioral assets, which was felt to be the most important to clinical and academic success were considered to be the least feasible to reliably assess. Within this domain, initiative, being self-motivated, intellectual curiosity, work ethic, communication skills, maturity and self-awareness, and thoughtfulness were viewed as most frequently reliably assessed from the application and interview process.

CONCLUSIONS

High quality applicants possess several behavioral assets that faculty deem are important to academic and clinical success. Adapting validated metrics for assessing these assets, may provide a solution for addressing subjectivity and other challenges scrutinized by critics of holistic review.

Margin Management and Adjuvant Therapy for Phyllodes Tumors: Practice Patterns of the American Society of Breast Surgeons Members

BACKGROUND

Phyllodes tumors (PTs) are rare breast neoplasms with variable clinical behavior by histologic type: benign, borderline, or malignant. Until recently, management guidelines recommended one approach for all subtypes.

METHODS

A 21-question survey was sent to American Society of Breast Surgeon members to evaluate management patterns by subtype. Surgeon demographics, decisions regarding management of margins, re-excision, surveillance, and synoptic reporting were collected. Chi-square or analysis of variance (ANOVA) were used as appropriate, with significance set at p < 0.05.

RESULTS

A total of 493 of 2969 surveys were completed for a response rate of 18.3%. Among the survey takers, 55% were fellowship trained, 72% were in practice > 10 years, and 82% performed > 100 breast cases per year. Although 25% of respondents enucleate a mass with clinical suspicion of a PT alone, this decreased to 18% if a preoperative core biopsy performed was suggestive of PT. For margin management, 47% do not re-excise positive margins for benign PTs, but 96% would for a borderline or malignant PTs (p < 0.001). Only 2% perform axillary staging for malignant PTs, and 90% refer borderline or malignant PTs for radiation. Two-year surveillance was performed by about half of respondents for benign PT. However, two-thirds of respondents would increase surveillance to 5 years for borderline or malignant PTs. Only 38% report a templated synoptic pathology report at their institution.

CONCLUSION

PT management patterns are evolving but still variable when looking at initial margin intent, decision for re-excision, radiation referral, pathologic reporting, and surveillance. This suggests the need for more specific management guidelines by subtype given differences in clinical behavior.

Cost-effectiveness of Choosing Wisely guidelines for axillary observation in women older than age 70 years with hormone receptor-positive, clinically node-negative, operable breast tumors

BACKGROUND

The Society for Surgical Oncology's Choosing Wisely guidelines recommend against sentinel lymph node biopsy (SLNB) in favor of observation in this population. Recent analyses reveal that this has not been widely adopted. The purpose of this cost-effectiveness analysis is to compare the costs and benefits associated with observation or SLNB in women >70 years old with hormone receptor-positive, clinically node-negative, operable breast cancer.

METHODS

A decision tree with Markov modeling was created to compare treatment strategies using long-term follow-up data from clinical trials in this population. Costs were estimated from published literature and publicly available databases. Breast cancer-specific health-state utilities were derived from the literature and expert opinion. One-way, 2-way, and probabilistic sensitivity analyses were conducted. A structural sensitivity analysis was performed to assess the effect of functional status and anxiety from nonevaluation of the axilla on cost-effectiveness. Costs and benefits, measured in life-years (LYs) and quality-adjusted life-years (QALYs), were tabulated across 10, 15, and 20 years and compared using incremental cost-effectiveness ratios (ICERs).

RESULTS

SLNB is not cost-effective from the payer or societal perspectives with ICERs of $138,374/LY and $131,900/LY, respectively. When QALYs were considered, SLNB provided fewer QALYs (SLNB, 10.33 QALYs; observation, 10.53 QALYs) at a higher cost (SLNB, $15,845; observation, $4020). Structural sensitivity analysis revealed that SLNB was cost-effective in certain patients with significant anxiety related to axillary observation (ICER, $39,417/QALY).

CONCLUSIONS

Routine SLNB in this population is not cost-effective. The cost-effectiveness of SLNB, however, is dependent on individual patient factors, including functional status as well as patient preference.

Timely cancer genetic counseling and testing for young women with breast cancer: impact on surgical decision-making for contralateral risk-reducing mastectomy

PURPOSE

Genetic testing (GT) can identify individuals with pathogenic/likely pathogenic variants (PV/LPVs) in breast cancer (BC) predisposition genes, who may consider contralateral risk-reducing mastectomy (CRRM). We report on CRRM rates in young women newly diagnosed with BC who received GT through a multidisciplinary clinic.

METHODS

Clinical data were reviewed for patients seen between November 2014 and June 2019. Patients with non-metastatic, unilateral BC diagnosed at age ≤ 45 and completed GT prior to surgery were included. Associations between surgical intervention and age, BC stage, family history, and GT results were evaluated.

RESULTS

Of the 194 patients, 30 (15.5%) had a PV/LPV in a BC predisposition gene (ATM, BRCA1, BRCA2, CHEK2, NBN, NF1), with 66.7% in BRCA1 or BRCA2. Of 164 (84.5%) uninformative results, 132 (68%) were negative and 32 (16.5%) were variants of uncertain significance (VUS). Overall, 67 (34.5%) had CRRM, including 25/30 (83.3%) PV/LPV carriers and 42/164 (25.6%) non-carriers. A positive test result (p < 0.01) and significant family history were associated with CRRM (p = 0.02). For the 164 with uninformative results, multivariate analysis showed that CRRM was not associated with age (p = 0.23), a VUS, (p = 0.08), family history (p = 0.10), or BC stage (p = 0.11).

CONCLUSION

In this cohort of young women with BC, the identification of a PV/LPV in a BC predisposition gene and a significant family history were associated with the decision to pursue CRRM. Thus, incorporation of genetic services in the initial evaluation of young patients with a new BC could contribute to the surgical decision-making process.

Disparities in Access to Postmastectomy Breast Reconstruction: Does Living in a Specific ZIP Code Determine the Patient's Reconstructive Journey?

BACKGROUND

Postmastectomy breast reconstruction (BR) has been shown to provide long-term quality of life and psychosocial benefits. Despite the policies initiated to improve access to BR, its delivery continues to be inequitable, suggesting that barriers to access have not been fully identified and/or addressed. The purpose of this study was to assess the influence of geographic location, socioeconomic status, and race in access to immediate BR (IBR).

METHODS

An institutional review board-approved observational study was conducted. All patients who underwent breast cancer surgery from 2014 to 2019 were queried from our institutional Breast Cancer Registry. A geographical analysis was conducted using demographic characteristics and patient's ZIP codes. Euclidean distance from patient home ZIP code to UPMC Magee Women's Hospital was calculated, and χ2, Student t test, Mann-Whitney, and Kruskal-Wallis tests was used to evaluate differences between groups, as appropriate. Statistical significance was set at P < 0.05.

RESULTS

Overall, 5835 patients underwent breast cancer surgery. A total of 56.7% underwent lumpectomy or segmental mastectomy, and 43.3% underwent modified, total, or radical mastectomy. From the latter group, 33.5% patients pursued BR at the time of mastectomy: 28.6% autologous, 48.1% implant-based, 19.4% a combination of autologous and implant-based, and 3.9% unspecified reconstruction. Rates of IBR varied among races: White or European (34.1%), Black or African American (27.7%), and other races (17.8%), P = 0.022. However, no difference was found between type of BR among races (P = 0.38). Moreover, patients who underwent IBR were significantly younger than those who did not pursue reconstruction (P < 0.0001). Patients who underwent reconstruction resided in ZIP codes that had approximately US $2000 more annual income, a higher percentage of White population (8% vs 11% non-White) and lower percentage of Black or African American population (1.8% vs 2.9%) than the patients who did not undergo reconstruction.

CONCLUSIONS

While the use of postmastectomy BR has been steadily rising in the United States, racial and socioeconomic status disparities persist. Further efforts are needed to reduce this gap and expand the benefits of IBR to the entire population without distinction.

Personalising therapy for early-stage oestrogen receptor-positive breast cancer in older women

Age is one of the most important risk factors for the development of breast cancer. Nearly a third of all breast cancer cases occur in older women (aged ≥70 years), with most cases being oestrogen receptor-positive (ER+). Such tumours are often indolent and unlikely to be the ultimate cause of death for older women, particularly when considering other comorbidities. This Review focuses on unique clinical considerations for screening, detection, and treatment regimens for older women who develop ER+ breast cancers-specifically, we focus on recent trends for de-implementation of screening, staging, surgery, and adjuvant therapies along the continuum of care. Additionally, we also review emerging basic and translational research that will further uncover the unique underlying biology of these tumours, which develop in the context of systemic age-related inflammation and changing hormone profiles. With prevailing trends of clinical de-implementation, new insights into mechanistic biology might provide an opportunity for precision medicine approaches to treat patients with well tolerated, low-toxicity agents to extend patients' lives with a higher quality of life, prevent tumour recurrences, and reduce cancer-related burdens.

Healthcare providers' perceived support from their organization is associated with lower burnout and anxiety amid the COVID-19 pandemic

BACKGROUND

Professional burnout represents a significant threat to the American healthcare system. Organizational and individual factors may increase healthcare providers' susceptibility or resistance to burnout. We hypothesized that during the COVID-19 pandemic, 1) higher levels of perceived organizational support (POS) are associated with lower risk for burnout and anxiety, and 2) anxiety mediates the association between POS and burnout.

METHODS

In this longitudinal prospective study, we surveyed healthcare providers employed full-time at a large, multihospital healthcare system monthly over 6 months (April to November 2020). Participants were randomized using a 1:1 allocation stratified by provider type, gender, and academic hospital status to receive one of two versions of the survey instrument formulated with different ordering of the measures to minimize response bias due to context effects. The exposure of interest was POS measured using the validated 8-item Survey of POS (SPOS) scale. Primary outcomes of interest were anxiety and risk for burnout as measured by the validated 10-item Burnout scale from the Professional Quality (Pro-QOL) instrument and 4-item Emotional Distress-Anxiety short form of the Patient Reported Outcome Measurement Information System (PROMIS) scale, respectively. Linear mixed models evaluated the associations between POS and both burnout and anxiety. A mediation analysis evaluated whether anxiety mediated the POS-burnout association.

RESULTS

Of the 538 participants recruited, 402 (75%) were included in the primary analysis. 55% of participants were physicians, 73% 25-44 years of age, 73% female, 83% White, and 44% had ≥1 dependent. Higher POS was significantly associated with a lower risk for burnout (-0.23; 95% CI -0.26, -0.21; p<0.001) and lower degree of anxiety (-0.07; 95% CI -0.09, -0.06; p = 0.010). Anxiety mediated the associated between POS and burnout (direct effect -0.17; 95% CI -0.21, -0.13; p<0.001; total effect -0.23; 95% CI -0.28, -0.19; p<0.001).

CONCLUSION

During a health crisis, increasing the organizational support perceived by healthcare employees may reduce the risk for burnout through a reduction in anxiety. Improving the relationship between healthcare organizations and the individuals they employ may reduce detrimental effects of psychological distress among healthcare providers and ultimately improve patient care.

Cutting Instruments to Cut Costs: A Simple Initiative with Breast Surgical Operating Room Trays that Resulted in Substantial Savings

BACKGROUND

A substantial expense in surgical care is incurred in the operating room (OR). We evaluated the financial impact of a systematic reduction in instrument tray contents on charges for breast surgery procedures.

METHODS

A catalog of OR trays historically used for breast procedures (excisional biopsy, segmental and total mastectomy with or without axillary staging) was reviewed by four dedicated breast surgeons and downsized to a single tray accommodating all surgeon preferences. A matched-case comparison was performed pre- and post-downsizing. Cost analysis for salary and benefits (S&B) and unit supply cost (USC) pre- and post-downsizing were carried out. Instrument number, OR tray weights, set-up, and breakdown times were also compared.

RESULTS

Post-downsizing, OR tray counts were reduced from 132 to 67 instruments (49%) and tray weight decreased from 30 to 20 pounds (33%). Scrub technician set-up and breakdown times were shorter by 22% and 25%, respectively. Comparing 449 matched cases (239 pre- and 210 post-downsizing), S&B and USC post-downsizing were decreased collectively for all procedures (p < 0.0001). With an average variance of S&B and USC (pre- to post-intervention) of $354, and an annualized case load of 813 operations, this could translate into S&B and USC savings of $287,802 per year.

CONCLUSION

Simply downsizing OR breast trays resulted in decreased combined S&B and USC per procedure, leading to a substantial cost savings for the healthcare system. This measure aligns with a value and quality-based approach to patient care and could be easily replicated across institutions and specialties.

Association of Tumor Molecular Subtype and Stage with Breast and Axillary Pathologic Complete Response After Neoadjuvant Chemotherapy for Breast Cancer

BACKGROUND

Axillary pathologic complete response (pCR) confers higher overall and recurrence-free survival than residual axillary disease. Although breast pCR (ypT0) is associated with a pathologically negative axilla (ypN0) in human epidermal growth factor receptor 2-positive (HER2+) and triple-negative breast cancer (TNBC), how clinical T (cT) and N (cN) staging are associated with ypN0 in other tumor subtypes is incompletely understood.

METHODS

A single-institution cancer registry was retrospectively reviewed for patients receiving neoadjuvant chemotherapy (NAC) followed by surgery from 2010 to 2018. Fisher's exact tests compared proportion of breast and axillary pCR by tumor subtype (hormone receptor [HR]-positive /HER2-,HR+/HER2+,HR-/HER2+,HR-/HER2-). Logistic regression determined factors associated with ypN0. Sensitivity analyses determined how cN status affected ypN status by tumor subtype.

RESULTS

The study enrolled 1348 patients. The median age was 54 years (interquartile range [IQR], 44-63 years), and 55% of the patients (n = 736) were postmenopausal. The tumor subtypes were HR+/HER2- (12%, n = 155), HR+/HER2+ (48%, n = 653), HR-/HER2+ (25%, n = 343), and TNBC (15%, n = 197). In the study, cT included T0 (1%, n = 18), T1 (20%, n = 272), T2 (53%, n = 713), T3 (17%, n = 230), and T4 (9%, n = 111), and cN included cN0 (51%, n = 687), cN1 (41%, n = 549), cN2 (5%, n = 61), and cN3 (3%, n = 43). Breast pCR and ypN0 occurred most in the HER2+ and TNBC subtypes. A negative association was found between ypN0 and age at diagnosis (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.97-0.99; p < 0.001), cT4 stage (OR, 0.29; 95% CI, 0.09-0.91; p = 0.034), and HR+ subtypes (HR+/HER2-: OR, 0.54; 95% CI, 0.31-0.94; p = 0.028; HR+/HER2+: OR, 0.60; 95% CI, 0.39-0.93; p = 0.024). The HR-/HER2+ subtype was associated with ypN0 (OR, 1.70; 95% CI, 1.05-2.73; p = 0.030), and cN2/cN3 was negatively associated with ypN0 in HR+/HER2+ disease (OR, 0.26; 95% CI, 0.11-0.61; p = 0.002), HR-/HER2+ disease (OR, 0.42; 95% CI, 0.22-0.77; p = 0.005), and TNBC (OR, 0.11; 95% CI, 0.03-0.40; p = 0.001).

CONCLUSION

Tumor subtype, clinical stage, and age at diagnosis may be important in consideration of de-escalation of axillary staging.

Outcomes After Sentinel Lymph Node Biopsy and Radiotherapy in Older Women With Early-Stage, Estrogen Receptor-Positive Breast Cancer

IMPORTANCE

Overtreatment of early-stage breast cancer with favorable tumor biology in older patients may be harmful without affecting recurrence and survival. Guidelines that recommend deimplementation of sentinel lymph node biopsy (SLNB) (Choosing Wisely) and radiotherapy (RT) (National Comprehensive Cancer Network) have been published.

OBJECTIVE

To describe the use rates and association with disease recurrence of SLNB and RT in older women with breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study obtained patient and clinical data from an integrated cancer registry and electronic health record of a single health care system in Pennsylvania. The cohort was composed of consecutive female patients 70 years or older who were diagnosed with early-stage, estrogen receptor-positive, ERBB2 (formerly HER2)-negative, clinically node-negative breast cancer from January 1, 2010, to December 31, 2018, who were treated at 15 community and academic hospitals within the health system.

EXPOSURES

Sentinel lymph node biopsy and adjuvant RT.

MAIN OUTCOMES AND MEASURES

Primary outcomes were 5-year locoregional recurrence-free survival (LRFS) rate and disease-free survival (DFS) rate after SLNB and after RT. Secondary outcomes included recurrence rate, subgroups that may benefit from SLNB or RT, and use rate of SLNB and RT over time. Propensity scores were used to create 2 cohorts to separately evaluate the association of SLNB and RT with recurrence outcomes. Cox proportional hazards regression model was used to estimate hazard ratios (HRs).

RESULTS

From 2010 to 2018, a total of 3361 women 70 years or older (median [interquartile range {IQR}] age, 77.0 [73.0-82.0] years) with estrogen receptor-positive, ERBB2-negative, clinically node-negative breast cancer were included in the study. Of these women, 2195 (65.3%) received SLNB and 1828 (54.4%) received adjuvant RT. Rates of SLNB steadily increased (1.0% per year), a trend that persisted after the 2016 adoption of the Choosing Wisely guideline. Rates of RT decreased slightly (3.4% per year). To examine patient outcomes and maximize follow-up time, the analysis was limited to cases from 2010 to 2014, identifying 2109 patients with a median (IQR) follow-up time of 4.1 (2.5-5.7) years. In the propensity score-matched cohorts, no association was found between SLNB and either LRFS (HR, 1.26; 95% CI, 0.37-4.30; P = .71) or DFS (HR, 1.92; 95% CI, 0.86-4.32; P = .11). In addition, RT was not associated with LRFS (HR, 0.33; 95% CI, 0.09-1.24; P = .10) or DFS (HR, 0.99; 95% CI, 0.46-2.10; P = .97). Subgroup analysis showed that stratification by tumor grade or comorbidity was not associated with LRFS or DFS. Low absolute rates of recurrence were observed when comparing the groups that received SLNB (3.5%) and those that did not (4.5%) as well as the groups that received RT (2.7%) and those that did not (5.5%).

CONCLUSIONS AND RELEVANCE

This study found that receipt of SLNB or RT was not associated with improved LRFS or DFS in older patients with ER-positive, clinically node-negative breast cancer. Despite limited follow-up time and wide 95% CIs, this study supports the continued deimplementation of both SLNB and RT in accordance with the Choosing Wisely and National Comprehensive Cancer Network guidelines.

Abstract PS13-19: Achieving a pathologically negative axilla after neoadjuvant chemotherapy for breast cancer is associated with presenting tumor size and subtype

Introduction: Axillary pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) confers higher overall and recurrence-free survival, compared to residual axillary disease. Recent findings suggest that pCR in the breast (ypT0) post-NAC is associated with a pathologically negative axilla (ypN0) in patients (pts) presenting with lower stage HER2+ and triple negative breast cancer (TNBC). Additional studies are needed to understand how clinical T (cT) and N (cN) staging are associated with ypN0 in other tumor subtypes, including hormone-receptor (HR) positive tumors. The ability to reliably predict axillary pathologic response post-NAC may allow identification of a subset of pts for whom axillary staging may be safely omitted. We hypothesize that tumor subtype and lower clinical stage at presentation are associated with ypN0.

Methods: A single institution cancer registry was retrospectively reviewed for pts receiving NAC followed by surgery from January 2010-June 2018. Fisher’s exact tests were used to compared proportion of breast and axillary pCR by tumor subtype (TNBC, HR+/HER2-, HR+/HER2+ and HR-/HER2+). Univariable logistic regression determined factors associated with ypN0. Multivariable logistic regression determined the association between ypN0 and tumor subtype adjusting for factors that retained significance on univariable analysis. Sensitivity analyses determined how cN status affected ypN status by tumor subtype.

Results: Of the 1348 pts who received NAC followed by surgery, median age was 54 (IQR 44-63); 59% (n=738) were postmenopausal. Proportion of tumor subtypes were: 15% (n=197) TNBC, 12% (n=155) HR+/HER2-, 48% (n=653) HR+/HER2+, and 25% (n=343) HR-/HER2+. Tumor size at diagnosis was: 1% (n=18) T0, 20% (n=272) T1, 53% (n=713) T2, 17% (n=230) T3 and 9% (n=111) T4. Clinical nodal staging at diagnosis was: 52% cN0 (n=695), 41% cN1 (n=550), 5% cN2 (n=61), and 3% cN3 (n=43). TNBC and HER2+ subtypes were associated with the highest rate of breast pCR and ypN0. On univariable analyses of the cN positive pts, younger age at diagnosis, non-postmenopausal status, oral contraceptive use, alcohol consumption, cT stage, cN stage and tumor subtype were significantly associated with ypN0 (Table1A). In the adjusted model, postmenopausal status, cT, and tumor subtype were associated with ypN0. Lower cT and HR- subtypes had significantly higher odds of ypN0 (Table 1B). In sensitivity analyses, cN2/cN3 was associated with lower odds of ypN0 compared to cN0/cN1 disease in TNBC (OR0.11 95%CI 0.03,0.40, p=0.001), HR-/HER2+ disease (OR0.42, 95%CI 0.22,0.77, p=0.005), and HR+/HER2+ (OR0.26 95%CI 0.11,0.61 p=0.002), but not in HR+/HER2- disease (OR1.17, 95%CI 0.25,5.57, p=0.838).

Conclusion: HR- and low cT stage at diagnosis are associated with ypN0 in this large cohort. Younger age, pre-menopausal status and cN stage may be important considerations in future investigations aimed at defining the subset of patients most likely to achieve ypN0 and ultimately to be considered for de-escalation of axillary staging post NAC.

A.Univariable logistic regression analysisVariableOdds Ratio95% Confidence Intervalp valueAge at diagnosis0.990.98, 0.99&lt;0.001RaceWhite1.060.70, 1.600.777Black0.600.17, 2.080.421Asian1.200.36, 4.000.768Postmenopausal0.760.60, 0.960.023BMI1.000.99. 1.000.424Oral contraceptive use1.250.95, 1.630.114Alcohol consumption1.601.05, 2.440.027

Tobacco use1.130.99, 1.290.064Family history of cancer1.250.92, 1.680.148Grade12.170.75, 6.250.15320.950.45, 2.010.89131.700.81, 3.590.163HistologyIDC1.451.10, 1.890.007ILC0.370.23, 0.60&lt;0.001Mixed0.950.68, 1.320.764Other0.440.18, 1.080.073Clinical T stage11.370.47, 3.980.56920.760.27, 2.160.60530.350.12, 1.020.05540.150.05, 0.450.001Clinical N stage10.140.11, 0.18&lt;0.00120.130.07, 0.23&lt;0.00130.110.06, 0.21&lt;0.001Tumor subtypeTNBC1.591.00, 2.530.049HR+/ HER2 -0.550.35, 0.870.010HR+/ HER2+0.690.47, 1.000.049HR-/ HER2 +1.641.09, 2.460.019B.Multivariable logistic regression analysisAge at diagnosis0.980.97, 0.99&lt;0.001Alcohol use1.190.74, 1.930.476HistologyIDC1.150.82, 1.610.414ILC0.570.32, 1.010.053Mixed1.080.71, 1.630.721Other0.790.28, 2.220.660Clinical T stage11.190.39, 3.580.76120.740.25, 2.160.58530.510.17, 1.540.23540.290.09, 0.910.034Clinical N stage10.130.10, 0.18&lt;0.00120.140.08, 0.26&lt;0.00130.100.05, 0.20&lt;0.001Tumor subtypeTNBC1.440.84, 2.470.181HR+/ HER2 -0.540.31, 0.940.028HR+/ HER2+0.600.39, 0.930.024HR-/ HER2 +1.701.05, 2.730.030

Citation Format: Sara P Myers, Gillian M Ahrendt, Joanna S Lee, Jennifer G Steiman, Atilla Soran, Ronald R Johnson, Priscilla F McAuliffe, Emilia J Diego. Achieving a pathologically negative axilla after neoadjuvant chemotherapy for breast cancer is associated with presenting tumor size and subtype [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 PS13-19.

Abstract PD4-08: Does genomic recurrence score predict for ipsilateral breast tumor recurrence after breast conservation therapy?

Purpose/ObjectivesGene profiling Recurrence Score (RS) assays are commonly used to identify patients with hormone receptor (HR) positive, HER-2 negative invasive breast cancer (IBC) who might benefit from systemic chemotherapy. More recently, the 21-gene recurrence score assay has been found to correlate with locoregional recurrence (LRR) after mastectomy (SWOG) or lumpectomy (NSABP). In the NSABP analysis, risk of ipsilateral breast tumor recurrence (IBTR) was not correlated with RS and was high in patients younger than 50 years of age irrespective of genomic score. However, tumor bed radiotherapy (RT) boost was not utilized in these protocols. The purpose of this study is to determine if RS predicts for IBTR or LRR in women treated with modern breast conserving therapy (BCT) using RT boost and optimal systemic treatment.

Materials/MethodsWe performed a retrospective review of patients with HR positive, HER-2 negative IBC who underwent gene profile testing and were treated at our institution with BCT and sentinel lymph node biopsy (SLNB) from 2013 to 2017. Both node negative and node positive patients were included. The Oncotype® 21-gene recurrence score assay was used in 84%, Mammaprint® in 12%, and Prosigna® in 4%. 97% received hormonal therapy (HT), 18% chemotherapy (CHT), 58% hypofractionated RT, and 96% a surgical bed RT boost. IBTR and LRR were measured from the end of local treatment to IBTR or LRR, with death or last follow up date as censoring events. The Kaplan-Meier method was used to estimate event-time probabilities for the above endpoints. Predictors of IBTR/LRR were analyzed using log rank tests between groups and with Cox regression for continuous variables. P-values &lt;0.05 were considered significant.

Results 686 evaluable patients were identified with median follow-up of 50 months (Interquartile range [IQR] 36-64 months). Median age was 61 years (IQR 53-68 years). 76% had invasive ductal carcinoma, 64% grade 2 disease, and 18% positive SLNB. RS of any type was low in 60% of patients and intermediate or high in 40%. Four-year IBTR was 0.2% (95% Confidence Interval [CI] 0.0-0.6%) for any low risk RS and 1.6% (95% CI 0.0 - 3.2%) for intermediate or high-risk RS (p = 0.01). Tumor grade was also predictive for IBTR (p &lt; 0.01), but age &lt; 50 was not (p = 0.4). For patients younger than 50, four-year IBTR was 0.9% (95% CI 0.0 - 2.6%) and not affected by RS (p = 0.231). On multivariate analysis, grade remained a significant predictor for IBTR (p = 0.04), but RS did not (p = 0.08). Four-year LRR was 0.5% (95% CI 0.0-1.3%) in patients with a low risk RS and 3.8% (95% CI 1.3-6.3%) in those with intermediate or high risk (p &lt; 0.01). Grade (p &lt; 0.01) and pathologic tumor size (p &lt; 0.01) were also correlated with LRR, although only RS (HR 5.14, 95% CI 1.02-25.9, p = 0.047) and pathologic tumor size on (HR 1.05, 95% CI 1.01- 1.09, p = 0.02) remained significant on multivariate analysis. Of the 125 patients with positive SLNB, 47% were treated with high tangents and 42% with comprehensive regional nodal irradiation. For node positive patients, LRR was not correlated with low versus intermediate or high RS (p = 0.07). However, if intermediate risk Oncotype scores were grouped with low risk Oncotype and Mammaprint scores, then LRR was 0.0% for low and intermediate risk and 9.1% for high risk (p &lt; 0.01).

ConclusionsIn this large single institution study, RS did not predict for IBTR in patients with HR positive, HER-2 negative invasive breast cancer in any age group treated with BCT utilizing a surgical bed RT boost and optimal systemic treatment. High RS did predict for high LRR because of higher regional recurrences and can be used as a guide to add comprehensive RT for node positive patients after BCT.

Citation Format: Adam H Richman, Ankur K Patel, Atilla Soran, Emilia J Diego, Priscilla F McAuliffe, Ronald R Johnson, Adam Brufsky, Vikram Gorantla, Jennifer Steiman, Joanna S Lee, Sushil Beriwal. Does genomic recurrence score predict for ipsilateral breast tumor recurrence after breast conservation therapy? [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 PD4-08.

Abstract PS1-10: Outcomes after sentinel lymph node biopsy and radiation therapy in women over 70 years old with ER+, HER2-, clinically node negative breast cancer

Overtreatment of early-stage breast cancer with favorable tumor biology in elderly patients can result in higher rates of complications and morbidities without impacting survival. Guidelines directed towards deimplementation of sentinel lymph node biopsy (SLNB) (Choosing Wisely) and radiation therapy (RT) (National Comprehensive Cancer Network) have been recommended. We sought to describe rates and impact on disease recurrence and survival of SLNB and RT in elderly patients with early breast cancer. Patient data were obtained from the cancer registry and electronic health record from University of Pittsburgh Medical Center, multicenter, single health care system. Consecutive female patients aged ≥ 70 with ER+, HER2- clinically node-negative breast cancer within a health care system from 2010 to 2018 were identified. Rates and patient characteristics associated with receipt of SLNB and RT, as well as local recurrence free survival (LRFS) and disease-free survival (DFS) were compared for patients that were diagnosed between 2010 and 2014 to allow for adequate follow up time. Cox proportional hazards regression was used to estimate hazard ratios (HRs) of mortality. Among 3,361 identified women, 2,195 (65.3%) received SLNB and 1,828 (54.4%) received RT. Rates of SLNB steadily increased (1.0% per year); this trend persisted in 2017 and 2018, even after the Society of Surgical Oncology adopted the Choosing Wisely Guidelines in 2016. During the same time period, rates of RT declined (3.4% per year). To examine outcomes, we limited the analysis to 2109 cases from 2010-2014; median (IQR) follow up time was 4.1 (2.5-5.7) years. Median (IQR) age was 77 (73-82) years. 1373 (65.1%) received SLNB and 1,219 (57.8%) received RT. Patients receiving SLNB were younger (P &lt; 0.001) with smaller (P &lt; 0.0001) and lower stage (P &lt; 0.0001) tumors. They had fewer comorbidities (P &lt; 0.001), longer follow-up times (P &lt; 0.001), were less likely on Medicaid/Medicare (P = 0.0091), and were more often seen at an academic center (P &lt; 0.0001). There was no difference in grade between those that did and did not receive SLNB (P = 0.31) and those that did and did not receive RT (P = 0.13). Multivariate cox proportional hazard analysis showed no effect of SLNB on LRFS (HR = 1.17, 95% CI 0.29-4.75, P = 0.83) or DFS (HR = 0.90, 95% CI 0.44-1.83, P = 0.77). Log rank test showed no difference in 5-year LRFS (P = 0.78) between patients who received (98.5%, 95% CI 97.7%-99.7%) and did not receive (98.1%, 95% CI 96.7%-99.5%) SLNB, but an increase was seen with 5-year DFS (P = 0.023), with 96.2% (95% CI 95.0%-97.4%) of patients disease-free among those who did receive SLNB vs. 93.0% (95% CI 90.6%-95.4%) with no SLNB. Multivariate cox proportional hazard analysis showed that RT was associated with improved LRFS (HR = 0.13, 95% CI 0.03-0.51, P &lt; 0.01) and DFS (HR = 0.32, 95% CI 0.15-0.68, P &lt; 0.01). Log rank test showed a difference in 5-year LRFS (P &lt; 0.0001) for those who received RT (99.4%, 95% CI 98.8%-100%) against those who did not (96.5%, 95% CI 95.0%-98.1%), and a similar difference in 5-year DFS (P &lt; 0.0001) in patients who did (97.0%, 95% CI 95.8%-98.1%) and did not (92.4%, 95% CI 90.2%-94.7%) receive RT. Lower age (OR = 0.89, 95% CI 0.87-0.92) and comorbidities (OR = 0.79, 95% CI 0.66-0.94) were associated with receipt of SLNB, while only age (OR = 0.91, 95% CI 0.88-0.94) was associated with receipt of RT.

We conclude that receipt of SLNB has no impact upon DFS or LRFS. This data supports deimplementation of SLNB for this patient population. Receipt of RT is important for controlling locoregional recurrence, supporting use of RT in this patient cohort.

Citation Format: Priscilla F McAuliffe, Neil M Carleton, Jian Zou, Yusi Fang, Stephen E Koscumb, Osama Shah, Fangyuan Chen, Sushil Beriwal, Emilia J Diego, Adam M Brufsky, Steffi Oesterreich, Steve D Shapiro, Robert Ferris, Leisha A Emens, George Tseng, Oscar C Marroquin, Adrian V Lee. Outcomes after sentinel lymph node biopsy and radiation therapy in women over 70 years old with ER+, HER2-, clinically node negative breast cancer [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 PS1-10.

Metaplastic breast carcinoma: a clinical-pathologic study of 97 cases with subset analysis of response to neoadjuvant chemotherapy

Metaplastic breast carcinoma is a rare heterogeneous category of breast cancer, often associated with a poor prognosis. Clinical-pathologic studies with respect to varied morphologic subtypes are lacking. There is also a dearth of studies assessing the response of metaplastic breast carcinoma to neoadjuvant chemotherapy. Cases of metaplastic breast carcinoma diagnosed between 2007 and 2017 were identified. Various clinical-pathologic variables were tested for association with survival. Patients who underwent neoadjuvant chemotherapy were assessed for pathologic response. Median age at diagnosis with metaplastic breast carcinoma was 64 years. With a median follow-up of 39 months, 26 patients (27%) recurred (24 distant and 2 loco-regional). The overall survival rate of the cohort was 66% (64/97). A number of variables were associated with survival in univariable analysis; however, in multivariable analysis, only lymph node status and tumor size (pT3 vs. pT1/2) were significantly associated with all survival endpoints: recurrence-free survival, distant recurrence-free survival, overall survival and breast cancer-specific survival. Twenty-nine of 97 (30%) patients with metaplastic breast carcinoma received neoadjuvant chemotherapy. Five (17%) patients achieved pathologic complete response. Matrix-producing morphology was associated with higher probability of achieving pathologic complete response (p = 0.027). Similar to other breast cancer subtypes, tumor size and lymph node status are prognostic in metaplastic carcinomas. The pathologic complete response rate of metaplastic breast carcinoma in our cohort was 17%, higher than previously reported. Although the matrix-producing subtype was associated with pathologic complete response, there was no survival difference with respect to tumor subtypes.

Is Multifocal Regression a Risk Factor for Ipsilateral Breast Tumor Recurrence in the Modern Era After Neoadjuvant Chemotherapy and Breast Conservation Therapy?

PURPOSE

Multifocal pattern of regression after neoadjuvant chemotherapy has been identified as a risk factor for ipsilateral breast tumor recurrence (IBTR). We aimed to determine the significance of multifocal regression as a predictor of IBTR after neoadjuvant chemotherapy and breast conservation therapy in the modern era.

METHODS AND MATERIALS

We retrospectively reviewed 346 patients treated between November 2009 and June 2017. Pattern of regression was categorized as pathologic complete response (pCR), unifocal (tumor present as a cohesive mass), limited multifocal (single cells or clusters of cells concentrated in 1 portion of the fibrotic area), or diffuse multifocal (cells spread over entire fibrotic area). IBTR was defined as new ipsilateral invasive or noninvasive breast tumor after breast conservation therapy. Predictive factors were analyzed using Cox regression.

RESULTS

Incidence of multifocal regression was 25.7% for the overall cohort and 12.2% for estrogen receptor (ER) negative/progesterone receptor (PR) negative/human epidermal growth factor receptor 2 (HER2) positive, 17.5% for triple-negative, 36.9% for ER+ or PR+/HER2-, and 38.5% for triple-positive (P < .001). With a median follow-up of 41.1 months, 4-year IBTR-free survival after pCR or unifocal regression versus multifocal regression was 94.1% versus 90.9% (P = .411). Pattern of regression (P = .010; compared to pCR, hazard ratio [HR] of 11.2 for diffuse multifocal regression, 1.65 for limited multifocal regression, and 3.81 for unifocal regression), phenotype (P = .001; compared to ER+ or PR+/HER2-, HR of 30.67 for ER-/PR-/HER2+, 25.30 for triple-negative, and 1.60 for triple-positive), and lack of nodal pCR (P = .004; HR of 3.78) predicted for IBTR on multivariate Cox regression. On multivariate subset analysis, pattern of regression and lymphovascular space invasion predicted for IBTR in hormone receptor-negative patients, but pattern of regression was not associated with IBTR for hormone receptor-positive patients.

CONCLUSIONS

Multifocal regression, hormone receptor-negative phenotype, and lack of nodal pCR predict for increased risk of IBTR after neoadjuvant chemotherapy. Although more common in hormone receptor-positive disease, multifocal regression was associated with worse outcome only in hormone receptor-negative patients.

Low Estrogen Receptor (ER)-Positive Breast Cancer and Neoadjuvant Systemic Chemotherapy: Is Response Similar to Typical ER-Positive or ER-Negative Disease?

OBJECTIVES

Pathologic complete response (pCR) rate after neoadjuvant chemotherapy was compared between 141 estrogen receptor (ER)-negative (43%), 41 low ER+ (13%), 47 moderate ER+ (14%), and 98 high ER+ (30%) tumors.

METHODS

Human epidermal growth factor receptor 2-positive cases, cases without semiquantitative ER score, and patients treated with neoadjuvant endocrine therapy alone were excluded.

RESULTS

The pCR rate of low ER+ tumors was similar to the pCR rate of ER- tumors (37% and 26% for low ER and ER- respectively, P = .1722) but significantly different from the pCR rate of moderately ER+ (11%, P = .0049) and high ER+ tumors (4%, P < .0001). Patients with pCR had an excellent prognosis regardless of the ER status. In patients with residual disease (no pCR), the recurrence and death rate were higher in ER- and low ER+ cases compared with moderate and high ER+ cases.

CONCLUSIONS

Low ER+ breast cancers are biologically similar to ER- tumors. Semiquantitative ER H-score is an important determinant of response to neoadjuvant chemotherapy.

Prognostic Significance of Modified Residual Disease in Breast and Nodes (mRDBN) Algorithm After Neoadjuvant Chemotherapy for Breast Cancer

OBJECTIVES

We hypothesized that prognostic accuracy of the residual disease in breast and lymph nodes (RDBN) method, which is calculated using residual tumor size, nodal involvement, and tumor grade, may be improved by incorporating residual tumor cellularity.

METHODS

Cases included 614 patients who underwent neoadjuvant therapy for breast cancer. Tumor size was adjusted for residual cellularity of invasive carcinoma and used to calculate modified RDBN (mRDBN) and compared with unmodified gross tumor size (gRDBN).

RESULTS

RDBN could be calculated in 428 cases. Relative risks of recurrence and death were significantly higher for RDBN-3 and RDBN-4 compared with RDBN-1. Kaplan-Meier analysis showed significant differences in disease-free survival and overall survival for estrogen receptor (ER)-negative/human epidermal growth factor receptor 2 (HER2)-negative and ER-positive/HER2-negative subgroups (P < .0001).

CONCLUSIONS

Both mRDBN and gRDBN provide prognostic information, particularly in HER2-negative carcinoma; however, mRDBN showed better stratification of RDBN-3 and RDBN-4 patients.

Abstract P6-09-14: Prognostic significance of a modified residual disease in breast and nodes (mRDBN) algorithm after neoadjuvant therapy for breast cancer

Background: Patients achieving pathologic complete response to neoadjuvant chemotherapy have excellent disease free and overall survival. For patients with residual disease, the residual disease in breast and lymph node (RDBN) method provides useful prognostic information. RDBN is calculated as follows: 0.2*tumor size (in cm)+lymph node status (0-3) + tumor grade (1-3). pCR, low, intermediate and high risk of recurrence categories correspond to RDBN index of 0, 0.1 to 2.9, 3 to &lt;4.4, and ≥ 4.4, respectively. We hypothesized that the prognostic accuracy of RDBN may be improved by also taking into account the residual tumor cellularity.

Methods: Retrospective review of 614 consecutive patients who underwent neoadjuvant therapy for breast cancer was performed. At our institution, tumor size/volume reduction in the breast is determined using the equation:

Estimated % tumor size reduction = [(pre-therapy clinical size – “revised” pathology tumor size)/pre-therapy clinical size]*100.

“Revised” pathology tumor size is calculated by multiplying the largest dimension of the gross tumor bed by the invasive tumor cellularity of the tumor bed (in comparison to the pre-therapy core biopsy sample). For example, if a 3 cm tumor bed has only 50% cellularity for invasive cancer (in comparison to pre-therapy core biopsy), the revised tumor size is 1.5 cm. Hence, we were able to use the “revised tumor size” for calculating the modified RDBN index (mRDBN). We also used gross tumor bed size for gross RDBN (gRDBN) to compare with mRDBN. mRDBN and gRDBN could be calculated on 459 of the 514 cases. Chi-Square statistical analysis was performed.

Results: Mean follow up was 33.1 months (median 31, range 4-70).

The results are shown in Table 1 & 2.

Table 1. Overall Recurrence and MortalityRDBN Score Category Overall Recurrence Mortality  nn (%)RR95% CI; pn (%)RR95% CI; pmRDBN (n=459)High5829 (50.0)19.63[7.22, 53.40]; p=&lt;0.000118 (31.0)16.24[4.97, 53.10]; p=&lt;0.0001Intermed16433 (20.1)7.9[2.86, 21.78]; p=&lt;0.000115 (9.1)4.79[1.41, 16.21]; p=0.006Low803 (3.8)1.47[0.34, 6.42]; p=0.694 (5.0)2.62[0.60, 11.41]; p=0.23pCR1574 (2.5)REF 3 (1.9)REF gRDBN (n=459)High8131 (38.3)15.02[5.49, 41.09]; p=&lt;0.000119 (23.5)12.28[3.74, 40.26]; p=&lt;0.0001Intermed14932 (21.5)8.43[3.05, 23.26]; p=&lt;0.000116 (10.7)5.62[1.67, 18.89]; p=0.003Low722 (2.8)1.09[0.20, 5.82]; p=12 (2.8)1.45[0.25, 8.51]; p=1pCR1574 (2.5)REF 3 (1.9)REF 

Table 2; Reclassification of gRDBN categoriesgRDBN mRDBN ReclassificationClassificationnLow (%)Intermed (%)High (%)Low7272 (100)0 (0)0 (0)Intermed1498 (5.4)140 (93.9)1 (0.7)High810 (0)24 (29.6)57 (70.4)

Conclusions: Both mRDBN and gRDBN provide prognostic information; however, separation of categories is improved with mRDBN (Table 1). mRDBN reclassified 30% of the high risk-gRDBN patients into intermediate risk category with a recurrence rate of 20%, leaving the 'true' high risk subgroup with a revised recurrence rate of 50% (Table 2). RDBN index also identified a group of low risk patients who have prognosis similar to patients with pCR.

Citation Format: Farrugia DJ, Landmann A, McAuliffe PF, Diego EJ, Johnson R, Bonaventura M, Soran A, Dabbs DJ, Clark B, Lembersky BC, Puhalla SL, Brufsky A, Jankowitz R, Davidson NE, Ahrendt GM, Bhargava R. Prognostic significance of a modified residual disease in breast and nodes (mRDBN) algorithm after neoadjuvant therapy for breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-14.

Case report of a large lactating adenoma with rapid antepartum enlargement

INTRODUCTION

Lactating adenomas are rare benign breast tumors, most commonly found during pregnancy and lactation. They are usually slow growing and smaller than 3cm in maximal diameter. Rare cases of giant lactating adenomas and rapid postpartum enlargement have been reported, but none have shown a giant lactating adenoma with rapid antepartum enlargement or antepartum surgical management.

CASE PRESENTATION

A 27 year-old pregnant woman presented at 28 weeks gestation with a 5cm left breast mass that doubled to 10cm within six weeks and was increasingly tender. Histopathologic examination of a core biopsy was consistent with a lactating adenoma. The mass was excised at 31 weeks gestation with no complications.

DISCUSSION

Lactating adenomas are common during pregnancy and need to be distinguished from breast cancer, a commonly diagnosed malignancy in pregnancy. They can be distinguished from carcinoma and other benign tumors like fibroadenoma under histopathologic examination. Rare cases of giant lactating adenomas with rapid postpartum enlargement that were managed by postpartum excision have been reported. However, a giant lactating adenoma with rapid antepartum enlargement, managed by excision in the third trimester of pregnancy, has not been reported.

CONCLUSION

Excision of a large, rapidly enlarging lactating adenoma in the third trimester of pregnancy is a safe and feasible management option.

Axillary Staging After Neoadjuvant Chemotherapy for Breast Cancer: A Pilot Study Combining Sentinel Lymph Node Biopsy with Radioactive Seed Localization of Pre-treatment Positive Axillary Lymph Nodes

BACKGROUND

Neoadjuvant chemotherapy (NAC) downstages axillary disease in 55 % of node-positive (N1) breast cancer. The feasibility and accuracy of sentinel lymph node biopsy (SLNB) after NAC for percutaneous biopsy-proven N1 patients who are clinically node negative (cN0) by physical examination after NAC is under investigation. ACOSOG Z1071 reported a false-negative rate of <10 % if ≥3 nodes are removed with dual tracer, including excision of the biopsy-proven positive lymph node (BxLN). We report our experience using radioactive seed localization (RSL) to retrieve the BxLN with SLNB (RSL/SLNB) for cN0 patients after NAC.

METHODS

We performed a retrospective review of a single-institution, prospectively maintained registry for the years 2013 to 2014. Patients with BxLN who received NAC and had RSL/SLNB were identified. All BxLNs were marked with a radiopaque clip before NAC to facilitate RSL.

RESULTS

Thirty patients with BxLN before NAC were cN0 after NAC and underwent RSL/SLNB. Median age was 55 years. Disease stage was IIA-IIIB. Twenty-nine of 30 had ductal cancer (12 triple negative and 16 HER-2 positive). One to 11 nodes were retrieved. Twenty-nine of 30 BxLN were successfully localized with RSL. Note was made of the BxLN-containing isotope and/or dye in 22 of 30. Nineteen patients had no residual axillary disease; 11 had persistent disease. All who remained node positive had disease in the BxLN.

CONCLUSIONS

RSL/SLNB is a promising approach for axillary staging after NAC in patients whose disease becomes cN0. The status of the BxLN after NAC predicted nodal status, suggesting that localization of the BxLN may be more accurate than SLNB alone for staging the axilla in the cN0 patient after NAC.