Mutational Status is Associated with a Higher Rate of Pathologic Complete Response After Neoadjuvant Chemotherapy in Hormone Receptor-Positive Breast Cancer

BACKGROUND

Pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) occurs in up to 20% of hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancers. Whether this differs among BRCA mutation carriers is uncertain. This study compared pCR between BRCA1/2 mutation carriers and matched sporadic control subjects.

METHODS

From November 2013 to January 2022, this study identified 522 consecutive women with clinical stage I to III HR+/HER2- breast cancer treated with NAC and surgery. The study matched BRCA1/2 mutation carriers 1:2 to non-carriers in terms of age, clinical tumor (cT) and nodal (cN) stage, and differentiation. Two-sample non-parametric tests compared baseline characteristics. Multivariable logistic regression assessed pCR (i.e., ypT0/ispN0) by BRCA1/2 mutational status.

RESULTS

Of the 522 women (median age, 50 years), 59 had BRCA1/2 mutations, 78% of which were clinically node positive. Anthracycline-based NAC was administered to 97%. More BRCA1/2 mutation carriers were younger, had cT1 tumors, and had poorly differentiated disease. After matching, 58 BRCA1/2 mutation carriers were similar to 116 non-carriers in terms of age (p = 0.6), cT (p = 0.9), cN stage (p = 0.7), and tumor differentiation (p > 0.9). Among the mutation carriers, the pCR rate was 15.5% for BRCA1/2, 38% (8/21) for BRCA1, and 2.7% (1/37) for BRCA2 versus 7.8% (9/116) for the non-carriers (p < 0.001). After NAC, 5 (41.7%) of the 12 BRCA1 mutation carriers converted to pN0 versus 10 (37%) of the 27 BRCA2 mutation carriers and 19 (20.9%) of the 91 non-carriers (p = 0.3). In the multivariable analysis, BRCA1 mutation status was associated with higher odds of pCR than non-carrier status (odds ratio [OR] 6.31; 95% confidence interval [CI] 1.95-20.5; p = 0.002), whereas BRCA2 mutation status was not (OR 0.45; 95% CI 0.02-2.67; p = 0.5).

CONCLUSIONS

This study showed that BRCA1 mutation carriers with HR+/HER2- breast cancers have a higher rate of pCR than sporadic cancers and may derive greater benefit from chemotherapy. The use of NAC to downstage these patients should be considered.

Does a brief surgeon training in negotiation theory principles decrease rates of contralateral prophylactic mastectomy?

PURPOSE

Despite the lack of any oncologic benefit, contralateral prophylactic mastectomy (CPM) use among women with unilateral breast cancer is increasing. This patient-driven trend is influenced by fear of recurrence and desire for peace of mind. Traditional educational strategies have been ineffective in reducing CPM rates. Here we employ training in negotiation theory strategies for counseling and determine the effect on CPM rates.

METHODS

In consecutive patients with unilateral breast cancer treated with mastectomy from 05/2017 to 12/2019, we examined CPM rates before and after a brief surgeon training in negotiation skills. This comprised a systematic framework for patient counseling utilizing early setting of the default option, leveraging social proof, and framing.

RESULTS

Among 2144 patients, 925 (43%) were treated pre-training and 744 (35%) post-training. Those treated in the 6-month transition period were excluded (n = 475, 22%). Median patient age was 50 years; most patients had T1-T2 (72%), N0 (73%), and estrogen receptor-positive (80%) tumors of ductal histology (72%). The CPM rate was 47% pre-training versus 48% post-training, with an adjusted difference of -3.7% (95% CI -9.4 to 2.1, p = 0.2). In a standardized self-assessment survey, all 15 surgeons reported a high baseline use of negotiation skills and no significant change in conversational difficulty with the structured approach.

CONCLUSION

Brief surgeon training did not affect self-reported use of negotiation skills or reduce CPM rates. The choice of CPM is a highly individual decision influenced by patient values and decision styles. Further research to identify effective strategies to minimize surgical overtreatment with CPM is needed.

Do non-classic invasive lobular carcinomas derive a benefit from neoadjuvant chemotherapy?

PURPOSE

Invasive lobular breast cancers (ILCs) respond poorly to neoadjuvant chemotherapy (NAC). The degree of benefit of NAC among non-classic ILC (NC-ILC) variants compared with classic ILCs (C-ILCs) is unknown.

METHODS

Consecutive patients with Stage I-III ILC treated from 2003 to 2019 with NAC and surgery were identified, and grouped as C-ILC or NC-ILC as per the original surgical pathology report, with pathologist (A.G.) review performed if original categorization was unclear. A subset of similarly treated invasive ductal cancers (IDCs) was identified for comparison. Clinicopathologic characteristics and pathologic complete response (pCR) rates were evaluated.

RESULTS

Of 145 patients with ILC, 101 (70%) were C-ILC and 44 (30%) were NC-ILC (IDC cohort: 1157 patients). ILC patients were older, more often cT3/T4 and cN2/N3, and less often high-grade compared to IDC patients. Those with NC-ILC were less often ER+/HER2- (55% versus 93%), and more often HER2 + (25% versus 7%) and TN (21% versus 0%, all p < 0.001). Breast pCR was more common among NC-ILC, but most frequent in IDC. Nodal pCR rates were also lowest among C-ILC patients, but similar among NC-ILC and IDC patients. On multivariable analysis, C-ILC (OR 0.09) and LVI (OR 0.51) were predictive of lack of breast pCR; non-ER+/HER2- subtypes and breast pCR were predictive of nodal pCR. When our analysis was repeated with patients stratified by receptor subtype, histology was not independently predictive of either breast or nodal pCR.

CONCLUSION

NC-ILC patients were significantly more likely to achieve breast and nodal pCR compared with C-ILC patients, but when stratified by subtype, histology was not independently predictive of breast or nodal pCR.

Omission of Intraoperative Frozen Section May Reduce Axillary Overtreatment Among Clinically Node-Negative Patients Having Upfront Mastectomy

BACKGROUND

The growing use of postmastectomy radiation/regional nodal irradiation (PMRT) has resulted in many women receiving both axillary dissection (ALND) and PMRT, increasing lymphedema rates. After developing standardized PMRT criteria, we adopted a policy of ALND omission among cN0 patients with 1-2 positive sentinel nodes (+SLNs) requiring PMRT. We evaluated how often overtreatment with ALND+PMRT was avoided with this approach.

METHODS

A retrospective review of a prospectively maintained database was performed beginning 1 year before policy adoption. Intraoperative SLN evaluation was routine pre- and post-policy. ALND was performed for SLN macrometastasis pre-policy, and selectively performed post-policy for 1-2 +SLNs based on PMRT criteria. ALND+PMRT was required for ≥ 3 +SLNs.

RESULTS

From March 1, 2018 to November 30, 2020, a total of 2207 cT1-3N0 patients had mastectomy and 231 had +SLNs; 109 (47%) were treated pre-policy and 122 (53%) post-policy. Most (81%) had 1-2 +SLNs. There was no change in rates of ALND+PMRT (64% pre-policy vs. 58% post-policy, p = 0.09), including in patients with 1-2 +SLNs (61% vs. 51%, p = 0.20). Post-policy, ALND was omitted in 9 (7%) patients recognized intraoperatively as PMRT candidates; avoidable ALND was performed in 40 (33%) patients not identified as PMRT candidates until receipt of final pathology. Overall, had intraoperative SLN evaluation been deferred, only 5.7% of patients would have required completion ALND: 2.2% (n = 49/2207) for ≥ 3 +SLNs and 3.5% (n = 77/2207) for 1-2 +SLNs without PMRT indication.

CONCLUSIONS

Most patients could have avoided ALND+PMRT if decision making was deferred until final pathology was available. Selective intraoperative SLN evaluation in cN0 patients having upfront mastectomy may reduce avoidable overtreatment.

The Effect of Age on Outcomes After Neoadjuvant Chemotherapy for Breast Cancer

BACKGROUND

Younger women (age ≤ 40 years) with breast cancer undergoing neoadjuvant chemotherapy (NAC) have higher rates of pathologic complete response (pCR); however, it is unknown whether axillary or breast downstaging rates differ by age. In this study, we compared pCR incidence and surgical downstaging rates of the breast and axilla post NAC, between patients aged ≤ 40, 41-60, and ≥ 61 years.

METHODS

We identified 1383 women with stage I-III breast cancer treated with NAC and subsequent surgery from November 2013 to December 2018. pCR and breast/axillary downstaging rates were assessed and compared across age groups.

RESULTS

Younger women were significantly more likely to have ductal histology, poorly differentiated tumors, and BRCA mutations; 35% of tumors were hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-), 36% were HER2-positive (HER2+), and 29% were triple negative (TN), with similar subtype distribution across age groups (p = 0.6). Overall, pCR rates did not differ by age, however among patients with TN tumors (n = 394), younger women had higher pCR rates (52% vs. 35% among those aged 41-60 years and 29% among those aged ≥61 years; p = 0.007) and were more likely to have tumors with high tumor-infiltrating lymphocyte (TIL) concentrations (p < 0.001). Downstaging to breast-conserving surgery (BCS) eligibility post NAC among initially BCS-ineligible patients was similar across age groups; younger women chose BCS less often (p < 0.001). Among cN1 patients (n = 813), 52% of women ≤40 years of age avoided axillary lymph node dissection (ALND) with NAC, versus 39% and 37% in the older groups (p < 0.001).

CONCLUSIONS

Younger women undergoing NAC for axillary downstaging were more likely to avoid ALND across all subtypes; however, overall pCR rates did not differ by age. Despite equivalent breast downstaging and BCS eligibility rates across age groups, younger women were less likely to undergo BCS.

Is local recurrence higher among patients who downstage to breast conservation after neoadjuvant chemotherapy?

BACKGROUND

In early studies, local recurrence (LR) rates were higher after neoadjuvant chemotherapy (NAC) in comparison with upfront surgery. Modern outcomes are uncertain, particularly among those who are initially breast-conserving surgery-ineligible (BCSi) and downstage to being breast-conserving surgery-eligible (BCSe).

METHODS

Among patients with cT1-3 breast cancer treated from 2014 to 2018 who were BCSe after NAC, clinicopathologic characteristics and LR were compared between initially BCSe patients and BCSi patients who downstaged. Breast-conserving surgery (BCS) eligibility was determined prospectively.

RESULTS

Among 685 patients, 243 (35%) were BCSe before and after NAC and had BCS; 282 (41%) were BCSi before NAC, downstaged to BCSe, and had BCS; and 160 (23%) were BCSi before NAC, downstaged to BCSe, and chose mastectomy. The median age was 52 years, and most cancers were cT1-2 (84%), cN+ (61%), and human epidermal growth factor receptor 2-positive (HER2+; 38%) or triple-negative (34%). Those who were BCSe before NAC had a lower cT stage, whereas those who chose mastectomy were younger (P < .05). NAC was usually ACT (doxorubicin, cyclophosphamide, and a taxane)-based (92%), 99% of HER2+ patients received dual blockade, and 99% of BCS patients received adjuvant radiation. At a median follow-up of 35 months, 22 patients (3.2%) had developed LR. The Kaplan-Meier 4-year LR rates were not different among the groups (1.9% for those who were BCSe before and after NAC, 6.3% for those who downstaged to being BCSe and underwent BCS, and 2.7% for those who downstaged and underwent mastectomy; P = .17).

CONCLUSIONS

LR rates are low after NAC and BCS, even among BCSi patients who downstage, and they are not improved in patients who downstage and choose mastectomy. Mastectomy can be safely avoided in BCSi patients who downstage with NAC.

Local Recurrence is Frequent After Heroic Mastectomy for Classically Inoperable Breast Cancers

BACKGROUND

Despite advances in neoadjuvant systemic therapy (NST), some patients with aggressive T4 breast cancers do not respond. The efficacy of 'heroic' mastectomy in maintaining local control is unclear.

METHODS

In consecutive patients with primary or recurrent T4 cancers with < 50% shrinkage on NST who underwent mastectomy from 2007 to 2017, clinicopathologic characteristics and locoregional recurrence (LRR) were examined.

RESULTS

Among 104 patients, 59 (57%) had primary T4M0, 12 (12%) had locally recurrent T4M0, and 33 (32%) had T4M1 disease. Median age was 58.5 years and the majority had high-grade (74%) ductal cancers (85%); 45 (44%) were estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-), 26 (25%) were HER2 positive (HER2+), and 31 (30%) were triple negative (TN). Postoperative complications developed in 41 (39%) patients. At a median follow-up of 37 months, 42 (40%) patients developed LRR. TN (hazard ratio [HR] 7.5) and HER2+ (HR 2.67) subtypes, lymphovascular invasion (LVI; HR 3.80), and positive margins (HR 4.09) were predictive of LRR. The 3-year LRR rate was highest and overall survival (OS) was lowest among patients with TN cancers, at 66% (95% confidence interval [CI] 48-83%) and 30% (95% CI 14-47%), respectively.

CONCLUSIONS

After heroic mastectomy, postoperative complications were frequent and LRR occurred in 40% of patients despite a median OS of 3.8 years. Among TN patients, the 3-year LRR rate of 66% and 3-year OS of 30% suggest limited surgery benefit. Careful patient selection is prudent when considering heroic mastectomy.

Margin Width and Local Recurrence in Patients Undergoing Breast Conservation After Neoadjuvant Chemotherapy

BACKGROUND

A margin of "no ink on tumor" has been established for primary breast conservation therapy (BCT), but the appropriate margin following neoadjuvant chemotherapy (NAC) remains controversial. We examined the impact of margin width on ipsilateral breast tumor recurrence (IBTR) in the NAC-BCT population.

METHODS

Consecutive patients receiving NAC-BCT were identified from a prospective database. The associations between clinicopathologic characteristics, margin width, and isolated IBTR were evaluated.

RESULTS

From 2013 to 2019 we identified 582 patients with 586 tumors who received NAC-BCT. The median age of the cohort was 54 years (IQR 45, 62); 84% of patients had cT1/T2 tumors and 61% were clinically node positive. The majority of tumors were HER2+ (38%) or triple negative (TN) (31%). Pathologic complete response was observed in 29%. Margin width was > 2 mm in 517 tumors (88%) and ≤ 2 mm in 69 (12%). At a median follow-up of 39 months, 14 patients had IBTR as a first event, with 64% occurring within 24 months of surgery. The 4-year IBTR rate was 2% (95% CI 1-4%), and there was no difference based on margin width (3% ≤ 2 mm vs 2% > 2 mm; p = not significant). On univariate analysis, clinical and pathologic T stage and receptor subtype, but not margin width, were associated with IBTR (p < 0.05). On multivariable analysis, TN subtype and higher pathologic T stage were associated with isolated IBTR (both p < 0.05).

CONCLUSION

Pathologic features and tumor biology, not margin width, were associated with IBTR in NAC-BCT patients.

Nodal Recurrence in Patients With Node-Positive Breast Cancer Treated With Sentinel Node Biopsy Alone After Neoadjuvant Chemotherapy-A Rare Event

Importance

Prospective trials have demonstrated sentinel lymph node (SLN) false-negative rates of less than 10% when 3 or more SLNs are retrieved in patients with clinically node-positive breast cancer rendered clinically node-negative with neoadjuvant chemotherapy (NAC). However, rates of nodal recurrence in such patients treated with SLN biopsy (SLNB) alone are unknown because axillary lymph node dissection (ALND) was performed in all patients, limiting adoption of this approach.

Objective

To evaluate nodal recurrence rates in a consecutive cohort of patients with clinically node-positive (cN1) breast cancer receiving NAC, followed by a negative SLNB using a standardized technique, and no further axillary surgery.

Design, Setting, and Participants

From November 2013 to February 2019, a cohort of consecutively identified patients with cT1 to cT3 biopsy-proven N1 breast cancer rendered cN0 by NAC underwent SLNB with dual tracer mapping and omission of ALND if 3 or more SLNs were identified and all were pathologically negative. Metastatic nodes were not routinely clipped, and localization of clipped nodes was not performed. The study was performed in a single tertiary cancer center.

Intervention

Omission of ALND in patients with cN1 breast cancer after NAC if 3 or more SLNs were pathologically negative.

Main Outcome and Measures

The primary outcome was the rate of nodal recurrence among patients with cN1 breast cancer treated with SLNB alone after NAC.

Results

Of 610 patients with cN1 breast cancer treated with NAC (median [IQR] age, 49 [40-58] years), 555 (91%) converted to cN0 and underwent SLNB; 234 (42%) had 3 or more negative SLNs and had SLNB alone. Median age was 49 years. Median tumor size was 3 cm; 144 (62%) were ERBB2 (formerly HER2)-positive, and 43 (18%) were triple negative. Most (212 [91%]) received doxorubicin-based NAC, 205 (88%) received adjuvant radiotherapy (RT), and 164 (70%) also received nodal RT. At a median follow-up of 40 months, there was 1 axillary nodal recurrence synchronous with local recurrence in a patient who refused RT. Among patients who received RT (n = 205), there were no nodal recurrences.

Conclusions and Relevance

This cohort study found that in patients with cN1 disease rendered cN0 with NAC, with 3 or more negative SLNs with SLNB alone, nodal recurrence rates were low, without routine nodal clipping. These findings potentially support omitting ALND in such patients.

Abstract PD4-05: Axillary recurrence is a rare event in node-positive patients. treated with sentinel node biopsy alone after neoadjuvant chemotherapy: Results of a prospective study

Background: Four prospective multi-institutional trials have demonstrated that clinically node-positive patients (cN1) who receive neoadjuvant therapy (NAC) and convert to cN0 can be reliably staged with sentinel lymph node biopsy (SLNB) with false-negative rates (FNRs) of &lt; 10%, when ≥ 3 SLNs are retrieved. Since study patients all had axillary lymph node dissection (ALND), the rate of axillary recurrence after SLNB alone is unknown. Of concern is the possibility that residual chemotherapy-resistant axillary disease could lead to higher recurrence rates than seen in the primary surgery setting for cN0 patients where SLN FNRs of 5-10% result in axillary recurrence in &lt; 1% of cases. Here we report regional recurrence rates in a prospectively defined cohort of cN1 patients receiving NAC, followed by a negative SLNB using a standardized technique, and no further axillary surgery. Methods: From 06/2014 to 02/2019, patients with cT1-3 biopsy-proven cN1 breast cancer who received NAC and converted to cN0 by physical exam were prospectively managed with SLNB with dual tracer mapping and omission of ALND if ≥ 3 SLNs were pathologically negative. Nodes were not routinely clipped, and retrieval of clipped metastatic nodes was not required. Pathologically negative SLNs were defined as the absence of any metastases including isolated tumor cells. Results: Of 610 cN1 patients treated with NAC, 555 (91%) converted to cN0 and had SLNB; 234 (42%) had ≥ 3 negative SLNs and were treated with SLNB alone. Median patient age was 49 years and median tumor size at presentation was 3 cm; 61% were HER2+ and 18% triple negative. Most (91%) received doxorubicin-based NAC and 88% received adjuvant radiotherapy (RT), with 80% (n = 164) of RT patients receiving nodal RT (Table). At a median follow-up of 35 months, there was only 1 (0.4%) axillary recurrence for the entire cohort, synchronous with a breast recurrence, in a patient who refused RT. Among patients who received RT (n = 205), there were no axillary recurrences. The 4-year rate of distant recurrence for all patients was 6.1% (95% CI, 3.4-10.7%) and 4-year overall survival was 93.9% (95% CI, 87.6-97.1%). Conclusion: In cN1 patients treated with NAC, rates of axillary recurrence in patients with ≥ 3 pathologically negative SLNs treated with SLNB alone were low, without routine nodal clipping. Although further follow-up is needed, multiple studies have shown that nodal recurrence is an early event, particularly in HER2+ and triple negative patients, who comprised the majority of the population. Our findings support omitting ALND in cN1 patients after NAC when the SLNs are negative using an optimal SLNB technique.

Table. Patient PopulationOverall cohort (n = 234)Age, years (median, IQR)49 (40, 58)Tumor size at presentation, cm (median, IQR)3.0 (2.2, 5.0)Number SLNs retrieved (median, IQR)4 (3, 5)Palpable nodes at presentation (n, %)179 (76%)HistologyDuctal211 (90%)Lobular and mixed7 (3%)Micropapillary and mixed10 (4%)Other3 (1%)Occult3 (1%)DifferentiationWell1 (0.5%)Moderate36 (15%)Poor196 (84%)Unknown1 (0.5%)Receptor StatusHR+/HER2-47 (20%)HR+/HER2+80 (34%)HR-/HER2+64 (27%)HR-/HER2-43 (18%)Breast SurgeryBCS118 (50%)Mastectomy116 (50%)Breast pCR¥Yes161 (70%)No70 (30%)NAC regimenAC-T197 (84%)AC-T + carbo15 (6.4%)TC8 (3.4%)Other14 (6%)Neoadjuvant anti-HER2 treatmentHP (dual-therapy)144 (100%)Adjuvant RTYes205 (88%)No*29 (12%)¥3 patients had occult primary breast cancer and were not included in breast pCR calculation; *6/29 patients who did not receive RT enrolled in NSABP B-51

Citation Format: Andrea V Barrio, Giacomo Montagna, Anita Mamtani, Varadan Sevilimedu, Hiram S Cody, III, Mahmoud El-Tamer, Mary L Gemignani, Alexandra S Heerdt, Tracy-Ann Moo, Melissa Pilewskie, George Plitas, Lisa Sclafani, Kimberly J Van Zee, Monica Morrow. Axillary recurrence is a rare event in node-positive patients. treated with sentinel node biopsy alone after neoadjuvant chemotherapy: Results of a prospective study [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 PD4-05.

Adoption of SSO-ASTRO Margin Guidelines for Ductal Carcinoma in Situ: What Is the Impact on Use of Additional Surgery?

BACKGROUND

Historically, more than one-third of patients with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery (BCS) underwent additional surgery. The SSO-ASTRO guidelines advise 2 mm margins for patients with DCIS having BCS and whole-breast radiation (WBRT). Here we examine guideline impact on additional surgery and factors associated with re-excision.

PATIENTS AND METHODS

Patients treated with BCS for pure DCIS from August 2015 to January 2018 were identified. Guidelines were adopted on September 1, 2016, and all patients had separately submitted cavity-shave margins. Clinicopathologic characteristics, margin status, and rates of additional surgery were examined.

RESULTS

Among 650 patients with DCIS who attempted BCS, 50 (8%) converted to mastectomy. Of 600 who had BCS as final surgery, 336 (56%) received WBRT and comprised our study group. One hundred twenty-eight (38%) were treated pre-guideline and 208 (62%) were treated post-guideline. Characteristics and margin status were similar between groups. The re-excision rate was 38% pre-guideline adoption and 29% post-guideline adoption (p = 0.09), with 91% having only one re-excision. Re-excision for ≥ 2 mm margins was uncommon (6% pre-guideline vs. 5% post-guideline). On multivariate analysis, younger age (OR 0.97, 95% CI 0.94-0.99, p = 0.02) and larger DCIS size (OR 1.43, 95% CI 1.2-1.8, p < 0.001) were predictive of re-excision; guideline era was not. Younger age (OR 0.93, 95% CI 0.9-0.97, p < 0.001) and larger size (OR 1.64, 95% CI 1.3-2.1, p < 0.001) were predictive of conversion to mastectomy, but residual tumor burden was low.

CONCLUSIONS

The SSO-ASTRO guidelines did not significantly change re-excision rates for DCIS in our practice, likely since re-excision for margins ≥ 2 mm was uncommon even prior to guideline adoption, dissimilar to historically observed variations in surgeon practices. Younger age and larger DCIS size were associated with additional surgery.

Selecting Node-Positive Patients for Axillary Downstaging with Neoadjuvant Chemotherapy

BACKGROUND

Axillary lymph node dissection (ALND) can be avoided in node-positive patients who receive neoadjuvant chemotherapy (NAC) if three or more negative sentinel lymph nodes (SLNs) are retrieved. We evaluate how often node-positive patients avoid ALND with NAC, and identify predictors of identification of three or more SLNs and of nodal pathological complete response (pCR).

METHODS

From November 2013 to July 2019, all patients with cT1-3, biopsy-proven N1 tumors who converted to cN0 after NAC received SLN biopsy (SLNB) with dual mapping and were identified from a prospectively maintained database.

RESULTS

630 consecutive N1 patients were eligible for axillary downstaging with NAC; 573 (91%) converted to cN0 and had SLNB, and 531 patients (93%) had three or more SLNs identified. Lymphovascular invasion (LVI; odds ratio [OR] 0.46, 95% confidence interval [CI] 0.24-0.87; p = 0.02) and increasing body mass index (BMI; OR 0.77, 95% CI 0.62-0.96 per 5-unit increase; p = 0.02) were significantly associated with failure to identify three or more SLNs. 255/573 (46%) patients achieved nodal pCR; 237 (41%) had adequate mapping. Factors associated with ALND avoidance included high grade (OR 2.51, 95% CI 1.6-3.94, p = 0.001) and receptor status (HR+/HER2- [referent]: OR 1.99, 95% CI 1.15-3.46 [p = 0.01] for HR-/HER2-, OR 3.93, 95% CI 2.40-6.44 [p < 0.001] for HR+/HER2+, and OR 8.24, 95% CI 4.16-16.3 [p < 0.001] for HR-/HER2+). LVI was associated with a lower likelihood of avoiding ALND (OR 0.28, 95% CI 0.18-0.43; p < 0.001).

CONCLUSIONS

ALND was avoided in 41% of cN1 patients after NAC. Increased BMI and LVI were associated with lower retrieval rates of three or more SLNs. ALND avoidance rates varied with receptor status, grade, and LVI. These factors help select patients most likely to avoid ALND.

Extranodal Tumor Deposits in the Axillary Fat Indicate the Need for Axillary Dissection Among T1-T2cN0 Patients with Positive Sentinel Nodes

BACKGROUND

The American College of Surgeons Oncology Group (ACOSOG) Z0011 trial demonstrated the safety of omitting axillary lymph node dissection (ALND) in T1-T2cN0 patients with fewer than three positive sentinel nodes (SLNs) undergoing breast-conservation therapy. While microscopic extracapsular extension (mECE) > 2 mm is associated with increased nodal burden, the significance of extranodal tumor deposits (ETDs) in the axillary fat is uncertain.

METHODS

Consecutive patients with T1-T2cN0 breast cancer undergoing sentinel node biopsy and ALND for SLN metastases from January 2010 to December 2018 were identified. ETDs were defined as intravascular tumor emboli or metastatic deposits in the axillary fat. Clinicopathologic characteristics and nodal burden were compared by ETD status.

RESULTS

Among 1114 patients, 113 (10%) had ETDs: 81 (72%) were intravascular tumor emboli and 32 (28%) were soft tissue deposits. Patients with ETDs had larger tumors (median 2.2 vs. 2.1 cm; p = 0.033) and more often had mECE (83% vs. 44%; p < 0.001). On univariable analysis, presence of ETDs (odds ratio [OR] 9.66, 95% confidence interval [CI] 6.36-14.68), larger tumors (OR 1.47, 95% CI 1.25-1.72), and mECE (OR 10.73, 95% CI 6.86-16.78) were associated with four or more additional positive non-SLNs (NSLNs; all p < 0.001). On multivariable analysis, ETDs remained associated with four or more positive NSLNs (OR 5.67, 95% CI 3.53-9.08; p < 0.001). ETDs were strongly associated with four or more positive NSLNs (OR 7.15, 95% CI 4.04-12.67) among patients with one to two positive SLNs (n = 925).

CONCLUSIONS

Among T1-T2cN0 patients with SLN metastases, ETDs are strongly associated with four or more positive NSLNs at ALND. Even among those who may otherwise meet the criteria for omission of ALND, the presence of ETDs in axillary fat warrants consideration of ALND.

Is Clinical Exam of the Axilla Sufficient to Select Node-Positive Patients Who Downstage After NAC for SLNB? A Comparison of the Accuracy of Clinical Exam Versus MRI

BACKGROUND

The National Comprehensive Cancer Network (NCCN) endorses sentinel lymph node biopsy (SLNB) in patients with clinically positive axillary nodes who downstage after neoadjuvant chemotherapy (NAC). In this study, we compared the accuracy of post-NAC MRI to clinical exam alone in predicting pathologic status of sentinel lymph nodes in cN1 patients.

METHODS

We identified patients with T0-3, N1 breast cancer who underwent NAC and subsequent SLNB from March 2014 to July 2017. Patients were grouped based on whether a post-NAC MRI was done. MRI accuracy in predicting SLN status was assessed versus clinical exam alone.

RESULTS

A total of 450 patients met initial study criteria; 269 were analyzed after excluding patients without biopsy-confirmed nodal disease, palpable disease after NAC, and failed SLN mapping. Median age was 49 years. Post-NAC MRI was done in 68% (182/269). Patients undergoing lumpectomy vs mastectomy more frequently received a post-NAC MRI (88 vs 54%, p < 0.001). All other clinicopathologic parameters were comparable between those who did and did not have a post-NAC MRI. Thirty percent (55/182) had abnormal lymph nodes on MRI. Among these, 58% (32/55) had a positive SLN on final pathology versus 42% (53/127) of patients with no abnormal lymph nodes on MRI and 52% (45/87) of patients who had clinical exam alone (p = 0.09). MRI sensitivity was 38%, specificity was 76%, and overall SLN status prediction accuracy was 58%.

CONCLUSIONS

Post-NAC MRI is no more accurate than clinical exam alone in predicting SLN pathology in patients presenting with cN1 disease. Abnormal lymph nodes on MRI should not preclude SLNB.

Was Reexcision Less Frequent for Patients with Lobular Breast Cancer After Publication of the SSO-ASTRO Margin Guidelines?

BACKGROUND

The Society of Surgical Oncology and American Society for Radiation Oncology consensus guidelines defined a negative margin for breast-conserving surgery (BCS) as no ink on tumor, and implementation has reduced rates of additional surgery for patients with invasive ductal cancer (IDC). The outcomes for invasive lobular cancer (ILC) patients are uncertain.

METHODS

This study identified patients who had stage 1 or 2 ILC treated with BCS from January 2010 to February 2018. The guidelines were adopted 1 January 2014. Clinicopathologic characteristics, margin status, and reexcisions were compared before and after adoption of the guidelines and with those of IDC patients treated from May 2013 to February 2015.

RESULTS

Among 745 early-stage ILC patients undergoing BCT, 312 (42%) were treated before the guidelines and 433 (58%) after the guidelines. Most clinicopathologic characteristics were similar between the two groups, with differences in lobular carcinoma in situ, lymphovascular invasion, and node-positivity rates. The overall rates of additional surgery declined significantly after the guidelines (31.4 to 23.1%; p = 0.01), but the difference did not reach significance for reexcisions (19.9 to 15.2%; p = 0.12) or conversions to mastectomy (11.5 to 7.9%; p = 0.099) individually. Between eras, no difference in incidence or number of tumor on ink or ≤ 2 mm margins was observed (all p = 0.2). Larger tumors, younger age, and pre-guideline era were independently associated with additional surgery. Only younger age was predictive of mastectomy. Among 431 pre-guideline and 601 post-guideline IDC patients, reexcisions declined from 21.3 to 14.8% (p = 0.008), and conversion to mastectomy was rare (0.6%). The magnitude of reduction in any additional surgery (interaction, p = 0.92) and reexcisions (interaction, p = 0.56) was similar between ILC and IDC.

CONCLUSIONS

Despite differences in growth pattern and conspicuity, guideline adoption significantly reduced additional surgery among ILC patients, with a magnitude of benefit similar to that among IDC patients.

Impact of Age on Locoregional and Distant Recurrence After Mastectomy for Ductal Carcinoma In Situ With or Without Microinvasion

BACKGROUND

Locoregional recurrence (LRR) after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) is increased in young women. We examined the impact of age on LRR and distant disease after mastectomy for DCIS ± microinvasion.

METHODS

We identified consecutive patients with DCIS ± microinvasion treated with mastectomy from 1995 to 2017. LRR was defined as recurrence at the ipsilateral chest wall or regional nodes.

RESULTS

Overall, 3121 cases were identified, of which 421 (13.5%) had DCIS + microinvasion. Median age was 49 years and median follow-up was 6.4 years; 821 were followed for 10 or more years. Thirty-four LRRs were observed: 33 (97%) were invasive, and 23 (68%) were in the chest wall alone. Cumulative 10-year LRR incidence was 1.4%. Age < 50 years, high grade, and DCIS + microinvasion were associated with LRR (p ≤ 0.001); however, margin status was not (p = 0.14). Adjusting for grade and DCIS + microinvasion, age < 50 years (hazard ratio [HR] 14.7, 95% confidence interval [CI] 3.5-61.5; p < 0.001) was associated with LRR. Compared with women ≥ 50 years of age, women age < 40 years had the highest risk (HR 27.0, 95% CI 6.0-121), and women age 40-49 years had intermediate risk (HR 11.8, 95% CI 2.8-50.5). The cumulative 10-year LRR incidence was 4.2% for women < 40 years of age, 2.0% for women 40-49 years of age, and 0.2% for women ≥ 50 years of age. Women age < 40 years had a 10-year distant disease rate of 1.6% versus women age 40-49 years (0.7%) and women age ≥ 50 years (0.7%) (log-rank p = 0.051). Grade, DCIS + microinvasion, and margins were unassociated with distant disease.

CONCLUSIONS

LRR after mastectomy for DCIS ± microinvasion is uncommon, but is more frequent among women < 50 years of age, particularly in those < 40 years of age. The 10-year LRR rate in this youngest group remains low at 4.2%. Young age is an independent risk factor for LRR after BCS or mastectomy.

Lobular Histology Does Not Predict the Need for Axillary Dissection Among ACOSOG Z0011-Eligible Breast Cancers

BACKGROUND

The American College of Surgeons Oncology Group (ACOSOG) Z0011 trial demonstrated that axillary lymph node dissection (ALND) may be omitted for women with two or fewer positive sentinel nodes (SLNs) undergoing breast-conservation therapy (BCT). Lobular histology comprises a minority of patients, and applicability to these discohesive cancers has been questioned.

METHODS

From August 2010 to March 2017, patients undergoing BCT for cT1-2N0 cancer with positive SLNs were prospectively managed with ALND for three or more positive SLNs or gross extracapsular extension (ECE). In this study, clinicopathologic characteristics and nodal burden were compared between pure/mixed invasive lobular cancer (ILC) and invasive ductal cancer (IDC) patients.

RESULTS

Among 813 consecutive patients, 104 (12.8%) had ILC and 709 (87.2%) had IDC. ILC was more often multifocal and low grade, and less frequently had lymphovascular invasion (all p < 0.001). ILC more often had SLN macrometastases (81.7% ILC vs. 69.4% IDC; p = 0.01) and more than 2 mm of ECE (30.8% ILC vs. 19.5% IDC; p = 0.03), but the proportions of cases with three or more positive SLNs were similar in the two groups (14.4% ILC vs. 9.9% IDC; p = 0.2). The ALND procedure was performed for 20 ILC patients (19.2%) compared with 97 IDC patients (13.7%) (p = 0.2). Additional positive nodes were found in 80% of the ILC patients versus 56.7% of the IDC patients (p = 0.09). The ALND and nodal burden rates were similar in the estrogen receptor-positive (ER+) subset analysis. In the multivariable analysis, lobular histology (p = 0.03) and larger tumors (p = 0.03) were associated with additional positive nodes. During a median follow-up period of 42 months, there were no isolated axillary recurrences.

CONCLUSIONS

Despite a higher proportion of SLN macrometastases and association with more positive nodes at ALND, lobular histology does not predict the need for ALND. ALND is not indicated on the basis of histology among patients otherwise meeting Z0011 criteria.

Unplanned readmissions following breast cancer surgery

BACKGROUND

Understanding the underlying factors associated with unplanned readmissions is an important first step toward interventions designed to improve quality of care. This study aimed to identify predictors of unplanned 30-day readmission using a national breast surgery cohort.

STUDY DESIGN

Using the National Cancer Database, we performed a review of patients undergoing surgery for breast cancer from 2006 to 2014. A multivariatble logistic regression model was generated to assess predictors of 30-day unplanned readmission.

RESULTS

Of 944,092 patients identified, 15,695 (1.7%) had an unplanned readmission within 30 days. Significant predictors of readmission included: increased procedure complexity, high co-morbidity score, Medicaid or lack of insurance, and low annual hospital volume; p < 0.0001.

CONCLUSION

Unplanned readmission following breast surgery is an uncommon event. However, our results demonstrate risk factors associated with higher rates of readmission following surgery. Understanding the underlying causes for readmission allows for identification of high-risk individuals and the design of targeted intervention programs.

Lobular Breast Cancer: Different Disease, Different Algorithms?

Invasive lobular carcinoma (ILC) is the second most common type of breast cancer, with a unique pathogenesis and distinct clinical biology. ILCs display a characteristic loss of E-cadherin, are largely estrogen receptor positive, HER2 negative, and low to intermediate grade. These features portend a favorable prognosis, but there is a tendency for late recurrences and atypical metastases. ILCs tend to be insidious and infiltrative, which can pose a challenge for diagnosis, and emerging data suggest they may have a propensity for a differing response to standard therapies.

Treatment Strategies in Octogenarians with Early-Stage, High-Risk Breast Cancer

BACKGROUND

Octogenarians with early-stage breast cancer often have low-risk tumor biology. However, optimal treatment strategies for those with high-risk biology remain unclear.

METHODS

We reviewed the records of women ages 80-89 years with biopsy-proven, Stage I-II invasive breast cancer who were referred for surgical evaluation from January 2001 through December 2010. High-risk was defined as human epidermal growth factor receptor-positive (HER2+), triple-negative (TN), or histologic grade 3 disease.

RESULTS

Among 178 patients, 40 (22%) were high-risk: 12 were grade 1-2 (10 HER2 + , 2 TN); 28 were grade 3 (7 HER2+, 6 TN, 15 estrogen receptor-positive (ER+)/HER2-). The high-risk group had larger tumors and more often had ductal histology and lymphovascular invasion than the low-risk group and was more likely to undergo mastectomy (18 vs. 5%, p = 0.02), radiotherapy (55 vs. 36%, p = 0.03), and chemotherapy (10 vs. 0%, p = 0.002). Endocrine therapy use was similar among ER+ patients in both groups. The four patients in the high-risk group given chemotherapy were HER2+ and received trastuzumab-based regimens, without any reported toxicities. At median follow-up of 67 months, 10% of the high-risk group had a recurrence (3 distant-only, 1 simultaneous locoregional and distant in a patient treated with mastectomy without radiotherapy).

CONCLUSIONS

Tailored locoregional and systemic therapy resulted in low incidence of failure in these octogenarians with high-risk cancers with low morbidity. Modern adjuvant therapies should be considered for elderly women with high-risk cancers in the absence of significant comorbidities.

Axillary Micrometastases and Isolated Tumor Cells Are Not an Indication for Post-mastectomy Radiotherapy in Stage 1 and 2 Breast Cancer

BACKGROUND

Randomized trials demonstrate equivalent locoregional control with sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND) for T1-2 micrometastatic breast cancer, but include few mastectomy patients. Consensus is lacking on indications for post-mastectomy radiotherapy (PMRT) in this population. Herein, we evaluate locoregional recurrence (LRR) in an unselected, modern cohort of T1-2 breast cancer patients with micrometastases or isolated tumor cells (ITCs; N0i+/N1mi) having a mastectomy.

METHODS

We identified patients with T1-2N0i+/N1mi breast cancer treated with mastectomy from January 2006 to December 2011. Recurrent, bilateral, and neoadjuvant cases were excluded. The primary outcome of interest was LRR.

RESULTS

Overall, 352 patients [211 (60%) with ITCs and 141 (40%) with micrometastases] were identified. 162 (46%) patients had SLNB alone and one node was positive in 295 (84%) cases; 31 (9%) patients had PMRT and 95% had systemic therapy. At a median 6 years of follow-up, the overall crude LRR rate was 2.8% (n = 9), with no axillary recurrences, and the crude LRR rate was 3.9% among those who had SNB alone. Those with LRR had a median age of 55 years, median tumor size of 1.7 cm, and ductal histology; the majority were high-grade (89%) and estrogen receptor positive (78%), with one positive node (89%). There was no association between LRR and receipt of PMRT (p = 0.4), SLNB versus ALND (p = 0.2), or number of positive nodes (p = 0.7) using the log-rank test.

CONCLUSIONS

LRR was infrequent among T1-2N0i+/N1mi patients treated with mastectomy without PMRT, with no axillary failures, suggesting that PMRT or nodal radiotherapy are not routinely indicated in this population.

The Optimal Treatment Plan to Avoid Axillary Lymph Node Dissection in Early-Stage Breast Cancer Patients Differs by Surgical Strategy and Tumor Subtype

BACKGROUND

Strategies to reduce the likelihood of axillary lymph node dissection (ALND) include application of Z0011 or use of neoadjuvant chemotherapy (NAC). Indications for ALND differ by treatment plan, and nodal pathologic complete response rates after NAC vary by tumor subtype. This study compared ALND rates for cT1-2N0 tumors treated with upfront surgery versus those treated with NAC.

METHODS

The ALND rates for cT1-2N0 breast cancer patients were compared by tumor subtype among women undergoing upfront surgery to NAC. Multivariable analysis with control for age, cT stage, and lymphovascular invasion, and stratification by subtype was performed.

RESULTS

The study identified 1944 cancers in 1907 women who underwent sentinel lymph node (SLN) biopsy with or without ALND (669 upfront breast-conserving surgeries [BCSs], 1004 upfront mastectomies, 271 NACs). Compared with the NAC group, the ALND rates in the BCS group were lower for estrogen receptor (ER), progesterone receptor-positive (PR⁺), human epidermal growth factor 2-negative (HER2^-) tumors (15 vs 34%; p < 0.001). The ALND rates in the upfront mastectomy group were higher than in the NAC group for HER2⁺ or TN tumors. In the multivariable analysis, receipt of NAC compared with upfront BCS remained significantly associated with higher odds of ALND in the ER/PR⁺ HER2^- subtype (hazard ratio [HR], 3.35; p < 0.001), whereas NAC versus upfront mastectomy remained significantly associated with lower odds of ALND in the HER2⁺ and TN subtypes (HR for HER2⁺, 0.19, p < 0.001; HR for TN, 0.25, p = 0.007).

CONCLUSION

The study showed that ALND rates differ according to surgery type and tumor subtype secondary to differing ALND indications and nodal response to NAC. These factors can be used to personalize treatment planning to minimize ALND risk for patients with early-stage breast cancer.

Pleomorphic lobular carcinoma in situ of the breast: a single institution experience with clinical follow-up and centralized pathology review

PURPOSE

The natural history of pleomorphic lobular carcinoma in situ (PLCIS) remains largely unknown.

METHODS

A pathology database search (1995-2012) was performed to identify patients diagnosed with an LCIS variant. Patients with synchronous breast cancer and/or no evidence of pleomorphism were excluded. Original slides were re-evaluated by three pathologists to identify a consensus cohort of PLCIS. Borderline lesions with focal atypia were classified as LCIS with pleomorphic features (LCIS-PF). Clinical data were obtained from medical records.

RESULTS

From 233 patients, we identified 32 with an LCIS variant diagnosis and no concurrent breast cancer. Following review, 16 cases were excluded due to lack of pleomorphism. The remaining 16 were classified as PLCIS (n = 11) and LCIS-PF (n = 5). 12/16 patients were treated with surgical excision ± chemoprevention. Patients with a prior breast cancer history and those having mastectomy were excluded from outcome analysis. Among the remaining 7 patients with PLCIS/LCIS-PF, 4/7 (57%) developed ipsilateral breast cancer at a median follow-up of 67 months. Median age at the time of breast cancer diagnosis was 56 years old and median time from PLCIS/LCIS-PF to cancer diagnosis was 59 months (range 45-66 months). The four cancers included 1 invasive lobular carcinoma (ILC), 1 microinvasive ILC, 1 invasive ductal carcinoma, and 1 ductal carcinoma in situ.

CONCLUSIONS

We confirm that PLCIS in isolation is indeed a rare entity, further contributing to the difficulty in determining the actual risk conferred by this lesion. Long-term follow-up data on larger cohorts are needed to define standardized management and outcomes for patients with PLCIS.

Do Calcifications Seen on Mammography After Neoadjuvant Chemotherapy for Breast Cancer Always Need to Be Excised?

BACKGROUND

This study aimed to determine the relationship between mammographic calcifications and magnetic resonance imaging (MRI) tumoral enhancement before and after neoadjuvant chemotherapy (NAC) and to assess the impact of these findings on surgical management.

METHODS

This Institutional Review Board-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study involved breast cancer patients who underwent NAC between 2009 and 2015. The study cohort comprised 90 patients with pre- and posttreatment MRI and mammograms demonstrating calcifications within the tumor bed either at presentation or after treatment. The data gathered included pre- and post-NAC imaging findings and post-NAC histopathology, particularly findings associated with calcifications. Comparisons were made using Fisher's exact test, with p values lower than 0.05 considered significant.

RESULTS

Complete resolution of MRI enhancement occurred for 44% of the patients, and a pathologic complete response (pCR) was achieved for 32% of the patients. No statistically significant correlation between changes in mammographic calcifications and MRI enhancement was found (p = 0.12). Resolution of enhancement was strongly correlated with pCR (p < 0.0001). The majority of the patients with pCR demonstrated complete resolution of enhancement (79%, 23/29). No statistically significant relationship was found between changes in calcifications and rates of pCR (p = 0.06). A pCR was achieved most frequently for patients with resolution of enhancement and new, increasing, or unchanged calcifications (p < 0.0001).

CONCLUSIONS

Although calcifications seen on post-NAC mammography may be associated with benign disease, loss of MRI enhancement does not predict the absence of residual tumor with sufficient accuracy to leave calcifications in place. Complete excision of tumor bed calcifications remains standard practice and a substantial limitation to NAC use for downstaging patients to be eligible for breast conservation treatment.

Are there patients with T1 to T2, lymph node-negative breast cancer who are "high-risk" for locoregional disease recurrence?

BACKGROUND

Indications for postmastectomy radiotherapy (PMRT) in patients with T1 to T2, lymph node-negative (N0) breast cancer with "high-risk" features are controversial. The European Organization for Research and Treatment of Cancer (EORTC) 22922 and National Cancer Institute of Canada Clinical Trials Group MA20 trials reporting improved 10-year disease-free survival with lymph node irradiation included patients with high-risk N0 disease, but, to the authors' knowledge, benefits in patients receiving modern systemic therapy are uncertain.

METHODS

The authors retrospectively identified patients with T1 to T2N0 disease who were treated with mastectomy from January 2006 through December 2011. High-risk features included age <40 years, multifocality/multicentricity, lymphovascular invasion, medial/central tumor location, and high nuclear grade.

RESULTS

Among 672 eligible patients, only 15 received PMRT and were excluded. Of the remaining 657 patients, 187 (28%) had 1 high-risk feature and 449 patients (68%) had ≥ 2 high-risk features. A total of 36 patients with unknown tumor grade were excluded from risk analysis. Approximately 98% of patients underwent sentinel lymph node biopsy alone and 86% received adjuvant systemic therapy. At a median of 5.6 years of follow-up, the locoregional disease recurrence (LRR) rate was 4.7% (31 patients). Increasing tumor size was found to be associated with LRR (hazard ratio, 1.70; P = .006), whereas other high-risk features were not (all P > .05). Receipt of systemic therapy decreased the LRR rate (hazard ratio, 0.40; P = .03). Although crude LRR rates increased from 3.8% to 9.4% with 1 versus ≥ 4 high-risk features, the number of risk factors was not found to be significantly associated with LRR (P = .54).

CONCLUSIONS

In the current study, a low crude LRR rate (4.7%) was observed in a large unselected cohort of patients with T1 to T2N0 breast cancer with high-risk features who were treated with mastectomy and systemic therapy without PMRT. Although increasing tumor size and the omission of systemic therapy were found to be predictive, other features did not confer a higher LRR risk either independently or together, and do not by themselves mandate the use of PMRT in this patient population. Cancer 2017;123:2626-33. © 2017 American Cancer Society.

Abstract P3-13-07: Are there patients with T1-T2, node-negative breast cancer who are high-risk for locoregional recurrence?

Background: Indications for post-mastectomy radiotherapy (PMRT) in T1-T2, node negative (N0) breast cancer patients with “high-risk” features are controversial based on lack of consensus as to what constitutes “high-risk”, and variable results of small retrospective studies. The EORTC 22922 and MA20 trials reporting improved 10-year disease-free survival with nodal irradiation included high-risk N0 patients but these patients were not analyzed separately and did not receive modern systemic therapy. We sought to evaluate long-term locoregional control in T1-T2N0 patients with high-risk features undergoing mastectomy in the contemporary era.

Methods: We retrospectively identified patients with T1-T2N0 breast cancer with ≥1 high-risk feature treated with mastectomy from 1/2006-12/2011. High-risk features were defined as age &lt;40 years, multifocal/multicentric disease, lymphovascular invasion (LVI), medial or central tumor location, and high nuclear grade. The primary outcome of interest was rate of LRR.

Results: Among 672 patients meeting inclusion criteria, 187 (28%) had 1 risk factor: 21 (3%) were age &lt;40 years, 132 (20%) were multifocal/multicentric, and 34 (5%) had LVI; 449 (67%) patients had ≥2 high-risk features, and 36 patients with unknown grade were excluded from risk analysis. PMRT was received by only 15 (2%) patients. Clinicopathologic characteristics of the 657 patients treated without PMRT are shown in Table 1.

Table 1: Clinicopathologic characteristics, n = 657 Median (Range)Age, years49 (24-89)Tumor size, cm1.4 (&lt;0.1-5.0) n (%)Ductal histology566 (86%)High nuclear grade*266 (40%)LVI232 (35%)Multifocal/multicentric447 (68%)Medial/central tumor226 (34%)Receptor status** ER+/HER2-438 (67%)HER2+123 (19%)ER-/HER2-70 (11%) n (%)Rate of LRR# of risk factors*  1183 (28%)3.8%2265 (40%)5.3%3143 (22%)4.9%4 or 532 (5%)9.4%*Unknown grade in 34 cases, excluded from risk analysis **Unknown receptor status in 26 cases

Sentinel node biopsy alone was performed in 98% of these patients. A median of 4 lymph nodes were retrieved (range 1-15). Adjuvant systemic therapy was received by 86% of patients. At median 5.6 years of follow-up, overall LRR rate was 4.7% (n = 31), with the majority (55%) of events involving the chest wall. Increasing tumor size was associated with LRR (HR 1.70, 95% CI 1.26–2.29, p = 0.006), while age, histology, grade, subtype, LVI, multifocality/multicentricity, and tumor location were not (all p &gt; 0.05). Although rate of LRR increased from 3.8% to 9.4% with 1 vs. ≥4 high-risk features, a comparison of 1 vs. 2 vs. 3 vs. ≥4 risk factors was not significant by Kaplan-Meier estimation (p = 0.54).

Conclusions: A low LRR rate of 4.7% was seen in this large unselected cohort of T1-T2N0 cancers with "high-risk" features treated by mastectomy and systemic therapy without PMRT. While increasing tumor size was predictive, other features did not confer a higher risk of LRR either independently or together, and do not by themselves mandate the use of PMRT in this population.

Citation Format: Mamtani A, Patil S, Stempel M, Morrow M. Are there patients with T1-T2, node-negative breast cancer who are high-risk for locoregional recurrence? [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 P3-13-07.

Pathologic Complete Response with Neoadjuvant Doxorubicin and Cyclophosphamide Followed by Paclitaxel with Trastuzumab and Pertuzumab in Patients with HER2-Positive Early Stage Breast Cancer: A Single Center Experience

OBJECTIVES

Trastuzumab (H) and pertuzumab (P) with standard chemotherapy is approved for use in the neoadjuvant setting for human epidermal growth receptor 2 -positive patients. A retrospective analysis was performed of patients treated with dose-dense (dd) doxorubicin and cyclophosphamide (AC) followed by paclitaxel (T), trastuzumab, and pertuzumab (THP) in the neoadjuvant setting. Here, the pathologic complete response (pCR) rates are reported.

METHODS

An electronic medical record review was conducted of patients treated with HP-based therapy in the neoadjuvant setting from September 1, 2013, to March 1, 2015. Data on patient demographics, stage of breast cancer, pathology reports, surgical data, and information on systemic therapy were collected. The pCR was defined as total (tpCR, ypT0/is ypN0), German Breast Group (GBG) pCR (ypT0 ypN0), breast pCR (bpCR) with in situ disease (ypT0/is) and without in situ disease (ypT0), and explored axillary pCR (ypN0).

RESULTS

Charts from 66 patients were reviewed, and 57 patients were evaluable for pCR. Median age was 46 years (range 26-68 years). Median tumor size was 4 cm. Of 57 patients, 53 (93%) had operable breast cancer (T1-3, N0-1, M0). Three patients (5.3%) had locally advanced disease (T2-3, N2-3, M0 or T4a-c, any N, M0), and 1 (1.7%) had inflammatory breast cancer (T4d, any N, M0). Overall, 44 (77%) and 13 (23%) had hormone receptor (HR)-positive and negative diseases, respectively. Median numbers of cycles of neoadjuvant treatment were as follows: AC (4, range 1-4), T (4, range 1-4), trastuzumab (6, range 3-8), and pertuzumab (6, range 2-8). In these 57 patients, the rates of tpCR and bpCR with in situ disease were demonstrated in 41/57 (72%) patients, and the rates of GBG pCR and bpCR without in situ disease were found in 30/57 (53%) patients. Of 26 patients with biopsy-proven lymph nodal involvement, axillary pCR occurred in 22 (85%) patients.

CONCLUSION

At a single center, the tpCR and GBG pCR rates of dd AC followed by THP are high at 72% and 53%, respectively. The Oncologist 2017;22:139-143Implications for Practice: This is the first study describing the role of doxorubicin and cyclophosphamide followed by paclitaxel and dual anti-HER2 therapy with trastuzumab and pertuzumab (ACTHP) in patients with early stage HER2-positive breast cancer. Total (breast + lymph node) pathological complete remission (pCR) remission (ypT0/is ypN0) and German Breast Group pCR rates (ypT0/ ypN0) were high at 72% and 53%, respectively, with the ACTHP regimen. Rate of axillary clearance in patients with known axillary involvement was high at 85%, which may translate into less extensive axillary surgeries in this subset in the future.

Is Routine Axillary Imaging Necessary in Clinically Node-Negative Patients Undergoing Neoadjuvant Chemotherapy?

BACKGROUND

The National Comprehensive Cancer Network guidelines recommend axillary imaging prior to neoadjuvant chemotherapy (NAC) in breast cancer patients who are clinically node negative (cN0) by physical examination. However, the benefit of this approach remains uncertain. The purpose of this study was to determine whether abnormal axillary imaging pre-NAC predicts nodal metastases post-NAC (ypN+) in cN0 patients.

METHODS

cN0 patients undergoing NAC followed by axillary surgery were identified. Rates of ypN+ were compared among patients with abnormal pre-treatment axillary imaging vs. normal or no pre-treatment imaging using Fisher's exact test.

RESULTS

From May 2008 to March 2016, 402 eligible cN0 patients were identified. The median age of the patients was 49.5 years, and the median tumor size was 4 cm. Of these patients, 38% were estrogen receptor-positive (ER+) and human epidermal growth factor receptor 2-negative (HER2-), 30% were HER2+ , and 32% were triple negative. All had pre-NAC mammograms, 40% axillary ultrasound, 83% MRI, and 51% PET. Abnormal nodes on imaging were seen in 208 patients (52%); 128 had pre-NAC node biopsy, and 75 were positive. Overall, 28% of the patients (n = 111) were ypN+ post-NAC. Although the incidence of ypN+ was significantly higher in patients with abnormal nodes on pre-NAC imaging (p = 0.001), 54% did not require axillary lymph node dissection (ALND) post-NAC. Among the patients with normal nodes on pre-NAC imaging, 20% were ypN+ post-NAC.

CONCLUSIONS

Half of patients with abnormal nodes on pre-NAC imaging did not require ALND post-NAC, while 20% of those with normal pre-NAC nodes had disease post-NAC, indicating that in cN0 patients already selected for NAC, axillary imaging pre-NAC does not predict the need for axillary surgery post-NAC with sufficient accuracy to be clinically useful.

How Often Is Treatment Effect Identified in Axillary Nodes with a Pathologic Complete Response After Neoadjuvant Chemotherapy?

BACKGROUND

False-negative rates (FNR) of sentinel node biopsy (SNB) after neoadjuvant chemotherapy (NAC) in node-positive (N+) breast cancer patients are <10 % when ≥3 negative SNs are obtained. Marking positive nodes has been suggested to reduce FNR. Identification of treatment effect in the nodes post-NAC is an alternative to decrease FNR. We evaluated the frequency of treatment effect in N+ patients after a pathologic complete response (pCR) with NAC.

METHODS

Biopsy-proven N+ patients receiving NAC were identified. Patients with nodal pCR after axillary lymph node dissection (ALND) or SNB with dual mapping and ≥3 SNs removed were evaluated for treatment effect; ALND and SNB patients were compared.

RESULTS

From January 2009 to December 2015, 528 N+ patients received NAC. Of these, 204 had a nodal pCR, 135 had an ALND, and 69 had SNB. Median age was 49 years, 15 % were hormone receptor positive (HR+)/HER2-, 27 % triple negative, and 58 % HER2+. The median number of nodes removed in ALND patients was 17 versus 4 in SNB patients. Treatment effect in nodes was identified in 192 patients (94 %) and was more common in ALND versus SNB patients (97 vs 88 %; p = .02). HR+ patients and patients without a breast pCR were less likely to have treatment effect in the nodes (p = .05). Other characteristics did not differ.

CONCLUSIONS

Following NAC, SNs with treatment effect were retrieved in 88 % of patients without marking nodes, suggesting that nodal clipping may not be necessary to achieve an acceptable FNR. Longer follow-up is needed to determine regional recurrence rates in the SN-only cohort.

Early Adoption of the SSO-ASTRO Consensus Guidelines on Margins for Breast-Conserving Surgery with Whole-Breast Irradiation in Stage I and II Invasive Breast Cancer: Initial Experience from Memorial Sloan Kettering Cancer Center

BACKGROUND

Reexcision rates in patients undergoing breast-conserving surgery (BCS) for early-stage invasive breast cancer are highly variable. The Society of Surgical Oncology (SSO) and American Society for Radiation Oncology (ASTRO) published consensus guidelines to help standardize practice. We sought to determine reexcision rates before and after guideline adoption at our institution.

METHODS

We identified patients with stage I or II invasive breast cancer initially treated with BCS between June 1, 2013, and October 31, 2014. Margins were defined as positive (tumor on ink), close (≤1 mm), or negative (>1 mm), and were recorded for both invasive cancer and ductal carcinoma-in situ (DCIS) components. Reexcision rates were quantified, characteristics were compared between groups, and multivariable logistic regression was performed.

RESULTS

A total of 1205 patients were identified, 504 before and 701 after the guideline adoption (January 1, 2014). Clinical and pathologic characteristics were similar between time periods. Reexcision rates significantly declined from 21.4 to 15.1 % (p = 0.006) after guideline adoption. A multivariable model identified extensive intraductal component (odds ratio [OR] 2.5, 95 % confidence interval [CI] 1.2-5.2), multifocality (OR 2.0, 95 % CI 1.2-3.6), positive (OR 844.4, 95 % CI 226.3-5562.5) and close (OR 38.3, 95 % CI 21.5-71.8) ductal carcinoma-in situ margin, positive (OR 174.2, 95 % CI 66.2-530.0) and close (OR 6.4, 95 % CI 3.0-13.6) invasive margin, and time period (OR 0.5, 95 % CI 0.3-0.9 for post vs. pre) as independently associated with reexcision.

CONCLUSIONS

Overall reexcision rates declined significantly after guideline adoption. Close invasive margins were associated with higher rates of reexcision than negative invasive margins in both time periods; however, the effect diminished in the postguideline adoption period. Thus, we expect continued decline in reexcision rates as adherence to guidelines becomes more uniform.

Early-Stage Breast Cancer in the Octogenarian: Tumor Characteristics, Treatment Choices, and Clinical Outcomes

BACKGROUND

Nodal staging with sentinel node biopsy (SLNB), post-lumpectomy radiotherapy (RT), and endocrine therapy (ET) for estrogen receptor-positive (ER+) tumors is valuable in the treatment of early-stage (stages 1 or 2) breast cancer but used less often for elderly women.

METHODS

This retrospective study investigated women referred for surgical evaluation of biopsy-proven primary early-stage invasive breast cancer from January 2001 to December 2010. Clinicopathologic features, treatment course, and outcomes for women ages 80-89 years and 50-59 years were compared.

RESULTS

The study identified 178 eligible women ages 80-89 years and 169 women ages 50-59 years. The elderly women more often had grade 1 or 2 disease (p = 0.003) and ER+ tumors (p = 0.007) and less frequently had undergone adjuvant therapies (all p ≤ 0.001). Lumpectomy was performed more commonly for the elderly (92 vs. 83 %, p = 0.02), and axillary surgery was less commonly performed (46 vs. 96 %; p < 0.001). Fewer elderly women had undergone post-lumpectomy RT (42 vs. 89 %; p < 0.001) and ET for ER+ tumors (72 vs. 95 %; p < 0.001). During the median follow-up period of 56 months for the 80- to 89-year old group and 98 months for the 50- to 59-year-old group, death from breast cancer was similar (4 vs. 5 %; p = 0.5). The two groups respectively experienced 7 versus 6 locoregional recurrences and 11 versus 13 distant recurrences.

CONCLUSIONS

The octogenarians had disease survivorship similar to that of the younger women despite less frequent use of adjuvant therapies, likely reflecting lower-risk disease features. Whether increased use of axillary surgery, post-lumpectomy RT, and/or ET for ER+ tumors would further improve outcomes is an important area for further study, but treatment should not be deferred solely on the basis of age.

Age and Receptor Status Do Not Indicate the Need for Axillary Dissection in Patients with Sentinel Lymph Node Metastases

BACKGROUND

The American College of Surgeons Oncology Group Z0011 trial demonstrated the safety of omitting axillary lymph node dissection (ALND) for women with fewer than three positive sentinel lymph nodes (SLNs) who are undergoing breast-conservation therapy (BCT). Because most of the women were postmenopausal with estrogen receptor (ER) positive cancers, applicability of ALND for younger patients and those with triple-negative (TN) or human epidermal growth factor receptor 2 (HER2) overexpressing (HER2+) tumors remains controversial.

METHODS

From August 2010 to December 2015, patients undergoing BCT for cT1-2N0 disease and found to have positive SLNs were prospectively followed. Axillary lymph node dissection was indicated for more than two positive SLNs or gross extracapsular extension. Clinicopathologic characteristics, axillary surgery, nodal burden, and outcomes were compared between the high-risk patients (TN, HER2+, or age <50 years) and the remaining patients, termed average risk patients.

RESULTS

Among 701 consecutive patients, 242 (35 %) were high risk: 31 (13 %) with TN, 48 (20 %) with HER2+, 130 (54 %) with age less than 50 years, and 33 (14 %) with more than one high-risk feature. The remaining 459 patients (65 %) were average risk. The high-risk patients were younger, had higher-grade tumors (p < 0.0001), and more often had abnormal nodes imaged (p = 0.02). In this study, SLNB alone was performed for 85 % high-risk versus 82 % average-risk cases (p = 0.39). A median of four versus three SLNs were excised (p = 0.04), and both groups had a median of one positive SLN. Additional positive nodes at ALND were found in 62 % high-risk patients versus 65 % average-risk patients (p = 0.8), with a median of three positive nodes in both groups. During a median follow-up period of 31 months, no patients experienced isolated axillary recurrences.

CONCLUSIONS

Axillary lymph node dissection was no more likely to be indicated for high-risk patients. For patients undergoing ALND, the nodal burden was similar. For patients otherwise meeting the American College of Surgeons Oncology Group (ACOSOG) Z0011 clinical eligibility criteria, ALND is not indicated on the basis of age or subtype.

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.

Diabetes insipidus uncovered during conservative management of complicated acute appendicitis

Diabetes insipidus (DI) arises from impaired function of antidiuretic hormone, characterized by hypovolemia, hypernatremia, polyuria, and polydipsia. This case is a reminder of the rare but challenging obstacle that undiagnosed DI poses in fasting surgical patients, requiring prompt recognition and vigilant management of marked homeostatic imbalances.

Nuclear Stat5a/b predicts early recurrence and prostate cancer-specific death in patients treated by radical prostatectomy

There is an urgent need for reliable markers to identify patients whose prostate cancer (PCa) will recur after initial therapy and progress to lethal disease. Gleason score (GS) is considered the most accurate predictive marker for disease-specific mortality after primary treatment of localized PCa. Most PCas cluster into groups of GS 6 and 7 with considerable variation in the disease recurrence and disease-specific death. In preclinical PCa models, Stat5a/b promotes PCa growth and progression. Stat5a/b is critical for PCa cell viability in vitro and for tumor growth in vivo and promotes metastatic dissemination of cancer in nude mice. Here, we analyzed the predictive value of high nuclear Stat5a/b protein levels in 2 cohorts of PCas: Material I (n = 562) PCas treated by radical prostatectomy (RP), and Material II (n = 106) PCas treated by deferred palliative therapy. In intermediate GS PCas treated by radical prostatectomy, high levels of nuclear Stat5a/b predicted both early recurrence (univariable analysis; P < .0001, multivariable analysis; HR = 1.82, P = .017) and early PCa-specific death (univariable analysis; P = .028). In addition, high nuclear Stat5a/b predicted early disease recurrence in both univariable (P < .0001) and multivariable (HR = 1.61; P = .012) analysis in the entire cohort of patients treated by RP regardless of the GS. Patients treated by deferred palliative therapy, elevated nuclear Stat5a/b expression was associated with early PCa-specific death by univariable Cox regression analysis (HR = 1.59; 95% CI = [1.04, 2.44]; P = .034). If confirmed in future prospective studies, nuclear Stat5a/b may become a useful independent predictive marker of recurrence of lethal PCa after RP for intermediate GS PCas.