Use of bilateral prophylactic nipple-sparing mastectomy in patients with high risk of breast cancer

BACKGROUND

Nipple-sparing mastectomy (NSM) is being performed increasingly for risk reduction in high-risk groups. There are limited data regarding complications and oncological outcomes in women undergoing bilateral prophylactic NSM. This study reviewed institutional experience with prophylactic NSM, and examined the indications, rates of postoperative complications, incidence of occult malignant disease and subsequent breast cancer diagnosis.

METHODS

Women who had bilateral prophylactic NSM between 2000 and 2016 were identified from a prospectively maintained database. Rates of postoperative complications, incidental breast cancer, recurrence and overall survival were evaluated.

RESULTS

A total of 192 women underwent 384 prophylactic NSMs. Indications included BRCA1 or BRCA2 mutations in 117 patients (60·9 per cent), family history of breast cancer in 35 (18·2 per cent), lobular carcinoma in situ in 29 (15·1 per cent) and other reasons in 11 (5·7 per cent). Immediate breast reconstruction was performed in 191 patients. Of 384 NSMs, 116 breasts (30·2 per cent) had some evidence of skin necrosis at follow-up, which resolved spontaneously in most; only 24 breasts (6·3 per cent) required debridement. Overall, there was at least one complication in 129 breasts (33·6 per cent); 3·6 and 1·6 per cent had incidental findings of ductal carcinoma in situ and invasive breast cancer respectively. The nipple-areola complex was preserved entirely in 378 mastectomies. After a median follow-up of 36·8 months, there had been no deaths and no new breast cancer diagnoses.

CONCLUSION

These findings support the use of prophylactic NSM in high-risk patients. The nipples could be preserved in the majority of patients, postoperative complication rates were low, and, with limited follow-up, there were no new breast cancers.

Abstract P5-18-01: Risk of contralateral breast cancer (CBC) in women with ductal carcinoma in situ (DCIS) with and without and synchronous lobular carcinoma in situ (LCIS)

Background: LCIS is considered a risk factor for bilateral breast cancer, but the effect of LCIS diagnosed concurrently with DCIS is not known. We sought to compare CBC and ipsilateral breast tumor recurrence (IBTR) rates in women with DCIS with and without synchronous LCIS treated with breast conserving surgery (BCS).

Methods: A prospectively maintained database of DCIS patients undergoing BCS from 2000-2011 was used to identify women with a contralateral breast at risk. Patients with synchronous ipsilateral LCIS found at core needle biopsy or surgical excision were included in the “DCIS + LCIS” group; those with contralateral or bilateral LCIS were excluded. Associations of patient, tumor, and treatment factors with CBC and IBTR were evaluated using logistic regression.

Results: Of the 1888 patients identified, 1475 (78%) had DCIS only and 413 (22%) had DCIS with synchronous LCIS. Median follow-up was 7.5 years (range 0-17 years). 305 patients had a subsequent breast event; 216 IBTR and 89 CBC.

The 5 and 10-year cumulative incidence of IBTR was similar in both groups: 6.3% and 14.4% for DCIS only, compared with 5.9% and 14.0% for DCIS + LCIS (p = 0.94), respectively. The 5 and 10-year cumulative incidence of CBC was significantly greater in the DCIS + LCIS group: 5.7% and 10.0%, compared with 2.4% and 5.0% for DCIS only (p < 0.001).

Table 1 summarizes uni-and multi-variable analyses of risk factors associated with CBC and IBTR among women with DCIS treated with BCS. After adjustment for other factors, CBC risk was more than 2-fold higher in the DCIS + LCIS group compared with the DCIS only group (HR 2.37, 95% CI 1.54-3.65, p < 0.001). There was no difference in IBTR risk based on presence of synchronous LCIS. Younger age and receipt of endocrine therapy were significantly associated with decreased risk of CBC.

Table 1:Risk factors associated with CBC and IBTR in patients with DCIS treated with BCS  Univariate Analysis Multivariate Analysis  Hazard Ratio (95% CI) Hazard Ratio (95% CI)  CBC IBTR CBC IBTRAge (continuous)1.02 (1.01-1.04) *0.99 (0.98-1.0)1.02 (1.0-1.04) *0.99 (0.97-1.0) *Presentation    Radiologic1111Clinical0.36 (0.11-1.14)1.56 (1.05-2.3) *0.41 (0.13-1.31)1.67 (1.12-2.47) *Family history    Yes1.32 (0.87-2.01)1.0 (0.76-1.32)1.33 (0.87-2.03)1.03 (0.78-1.35)Grade    Low1111Intermediate/high1.83 (1.0-3.37)1.32 (0.93-1.88)1.74 (0.92-3.29)1.62 (1.11-2.35) *Radiation    Yes1.16 (0.75-1.8)0.7 (0.54-0.92) *1.14 (0.71-1.82)0.64 (0.48-0.86) *Endocrine Therapy    Yes0.43 (0.23-0.81) *0.51 (0.35-0.74) *0.42 (0.22-0.8) *0.53 (0.36-0.77) *DCIS group    DCIS only1111DCIS + LCIS2.28 (1.49-3.5) *0.99 (0.71-1.36)2.37 (1.54-3.65) *0.99 (0.71-1.37)* p < 0.05

Conclusions: LCIS diagnosed concurrently with DCIS is not associated with IBTR, but increases the risk of CBC two-fold. Endocrine therapy should be considered both for the index DCIS and for prevention of subsequent CBC.

Citation Format: Miller ME, Muhsen S, Zabor EC, Flynn J, Olcese C, Giri D, Van Zee KJ, Pilewskie M. Risk of contralateral breast cancer (CBC) in women with ductal carcinoma in situ (DCIS) with and without and synchronous lobular carcinoma in situ (LCIS) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-18-01.

Abstract P6-13-07: Chemotherapy with and without trastuzumab or no treatment in elderly patients with HER2 amplified breast cancer at a single center

Introduction

Trastuzumab with systemic chemotherapy has shown an improvement in outcomes for patients (pts) with HER2 amplified/overexpressed (HER2+) breast cancer. Pts enrolled onto trials were young with a minority of pts at ≥65 years (yrs) of age. Herein, we report the administration of systemic treatment (ST) (chemotherapy and/or trastuzumab) verus no treatment in elderly pts at a single center.

Methods

Patients ≥65 yrs with stage I-III HER2+ (defined as IHC 3+ or FISH >2.0) breast cancer, treated at Memorial Sloan Kettering Cancer Center between 2000-2012, were retrospectively identified from our database.

Clinicopathologic features were retrieved and co-morbidity indexes (CI) were calculated. Pts were divided by hormone receptor (HR) (defined as ER >10% and/or PR >10%) status into HER2+HR- and HER2+HR+. Each group was further divided by use of ST into: chemotherapy and trastuzumab (CT+T), chemotherapy alone (CT) or no systemic treatment (No Rx). Patients receiving neoadjuvant ST or trastuzumab only as ST were excluded from the KM analysis. Primary objective was to identify patterns of treatment recommendation in the elderly population. We explored disease-free survival (DFS) as estimated using the Kaplan-Meier (KM) method.

Results

We identified 300 pts ≥65 yrs with HER2+ tumors. 128 (42.7%) were HER2+HR- and 172 (57.3%) were HER2+HR+. The median follow-up for all patients was 6.1 years (range, 0.07-16.7).

In the HER2+HR- group, 63 (49.2%) patients received CT+T, 25 (19.5%) CT alone, and 40 (31.3%) had no Rx. Anthracycline based chemotherapy was administered to 57/88 (65%) of patients on CT. Women receiving chemotherapy with or without trastuzumab were younger (65-70 vs >70 years of age) (p=.002) and had more advanced tumor stages (p=.003). Their respective 5-yr DFS KM estimates were 0.84, 0.80, and 0.61 (logrank p=0.06).

In the HER2+HR+ group, 77 (44.8%) patients received CT+T, 22 (12.8%) CT alone, and 73 (42.2%) had no Rx. Anthracycline based chemotherapy was administered to 51/99 (51%) of patients on CT. Endocrine therapy was given to 153/172 (89%) of the total cohort. Women receiving chemotherapy with or without trastuzumab were younger (p<.001), and had higher nuclear grade (NG) (p=.04), more lymphovascular invasion (<.001) and more advanced tumor stages (p=.002). Their respective 5-yr DFS KM estimates were 0.84, 1.00, and 0.83 (log rank p=0.02).

Conclusions

At a single center, in the elderly populations at ≥65 years of age with HER2+ HR- and HER2+HR+ breast cancer, pts who received systemic treatment were younger and had higher stage of disease than those who received no treatment. In an exploratory analysis, there appeared to be a benefit of systemic treatment in pts in the HER+HR- group.

Citation Format: Muhsen S, Dang C, Plitas G, Seier K, Stempel M, Patil S, Morrow M, El-Tamer M. Chemotherapy with and without trastuzumab or no treatment in elderly patients with HER2 amplified breast cancer at a single center [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-13-07.

Abstract P6-13-05: Frequency of delivery of systemic chemotherapy in elderly versus younger patients with triple negative breast cancer

Introduction

Chemotherapy (CT) is the standard of care for most triple negative breast cancer (TNBC). Chemotherapy is less commonly recommended in older than younger patients. We aim to explore the frequency of CT delivered in elderly patients when compared to young patients.

Methods

Patients ≤50yrs and ≥70 yrs with stage I-III TNBC defined as ER <10% PR < 10% HER2 IHC < 3+ or FISH < 2.0 and treated at our institution from 2000-2011 were identified from our institutional breast cancer database. Clinicopathologic features were retrieved and co-morbidity indexes (CI) were calculated. Patients were grouped by age and CT use, and features were compared between groups using chi-square tests. Cause of death was reported as dead of disease (DOD) or dead of other causes (DOC) when available; otherwise, it was recorded as dead of unknown causes (DUC). OS survival was estimated using the Kaplan-Meier (KM) methods. Cumulative incidence functions for competing risks were calculated and compared between groups using Gray's test. Competing risks regression was performed for multivariate analysis.

Results

We identified 901 pts with TNBC; 664 (73.7%) were ≤50yrs and 237 (26.3%) were ≥70 yrs. Median followup is 7 yrs (range, 0-16.8yrs).

Younger women diagnosed with TNBC were more likely to have stronger family history of breast cancer (p<.001), to present with palpable masses (p<.001), higher nuclear grade (NG) (p<.001), larger tumors (p=.04), more involved nodes (p=.01), advanced tumor stage (p=.02) and to receive systemic chemotherapy (<.001). Anthracycline-based chemotherapy was administered to 486 (80.3%) in women ≤50yrs and only to 42 (36.5%) in the ≥70 yrs cohort (p<0.001). Chemotherapy data was missing on 2 pts in ≤50 yrs and 4 pts ≥70 for a total cohort of 662 patients ≤50 yrs and 233 pts ≥70 yrs.

The 5 year rates of DOD were similar between both groups at 10.6% (range, 8.3-13.2) for pts ≤50yrs and 10.8% (range, 7.0-15.4) (p=0.52) for the older group; meanwhile, the 5 year OS rates were significantly different between both groups at 87.5% (range, 84.7-90.0) for pts ≤50yrs and 74.3% (range, 68.2-80.0) (p<.001) for the older group since older women die at higher rates from causes other than disease.

CT was given to 115 (49%) patients of the ≥70 yrs cohort with a selection biased by larger tumors (p<.001) and more advanced stages (p<.001). There was no significant difference however, between tumor size (p=0.47) and stage (p=0.98) when comparing the 609 (92%) pts ≤50 yrs and the 115 (49%) of ≥70 yrs patients who received CT.

When categorized based on age and receipt of CT, in the 662 pts ≤ 50 yrs, 609 (92%) and 53 (8%) received CT vs no CT respectively; in the 233 pts ≥70 yrs, 115 (49%) and 118 (50%) received CT vs no CT; the cumulative incidence curves for DOD were not statistically different for the four groups (p=0.85) at 5 years.

Conclusions

In our series, CT was given to 92% of patients ≤ 50 yrs of age. In the elderly pts ≥ 70 yrs of age, CT was limited to 50% of patients, namely those with worse clinicopathologic features.

Citation Format: Muhsen S, Dang C, Plitas G, Knezevic A, Stempel M, Patil S, Morrow M, El-Tamer M. Frequency of delivery of systemic chemotherapy in elderly versus younger patients with triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-13-05.

Patient characteristics associated with the decision to undergo bilateral prophylactic mastectomy for lobular carcinoma in situ

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Background: Women at increased risk for breast cancer due to a diagnosis of lobular carcinoma in situ (LCIS) have three management options: high risk surveillance +/- chemoprevention (CP) or bilateral prophylactic mastectomy (BPM). Among a large cohort of women with LCIS, we previously reported there were no differences between women choosing CP compared to those choosing surveillance alone. The purpose of this study was to identify patient factors associated with the decision to pursue BPM for LCIS.

Methods: We reviewed our prospectively maintained LCIS database to identify women choosing BPM (1995-2009). Comparisons were made between patients who chose BPM versus those who chose high risk surveillance +/- CP.

Results: Among 995 pts with LCIS, 795 (80%) chose surveillance alone, 149 (15%) chose CP and 51 (5%) chose BPM. Compared to patients electing surveillance +/- CP patients who pursued BPM were younger at age of LCIS diagnosis (48 vs. 52 yrs, p < 0.001), more likely to have bilateral biopsies with LCIS (14% vs. 3%, p = 0.002) and more likely to be premenopausal (82% vs. 57%, p < 0.001). Patients choosing BPM were also more likely to have additional risk factors for breast cancer including: stronger family histories and extremely dense breasts (Table). Occult breast cancer was found in 4 (8%) BPM patients. At a median follow-up of 54 months (range 0-190 mos), 120/944 (13%) patients in the surveillance +/- CP group developed breast cancer.

Conclusions: High-risk surveillance alone is the preferred management option for women with LCIS at our institution. Patients electing BPM are younger and more likely to have other associated risk factors for developing breast cancer. Further research to define how the increased risk imparted by LCIS is augmented by these factors may allow for better risk stratification and more informed discussions with patients.

[Table: see text]

Abstract P4-06-07: PI3K Mutations Are More Common in Low Grade DCIS

Background: DCIS is a non-obligate precursor to invasive breast cancer yet it remains difficult to predict which lesions will progress or over what time interval. Factors associated with a higher risk of progression include high histologic grade and HER2 amplification. HER2 signaling via the PI3K pathway is associated with accelerated invasiveness in laboratory models and mutations in the helical domain of PI3K have been associated with a worse prognosis in invasive cancer. We hypothesized that PI3K pathway mutations are associated with higher risk of progression in DCIS and therefore would be more common in high grade DCIS.

Methods: 195 cases of pure DCIS were identified from the MSKCC breast service database (1999-2003). All cases were reviewed by a single pathologist to assign histologic grade. Sections were obtained from archived formalin-fixed paraffin embedded (FFPE) blocks for manual microdissection to isolate pure DCIS lesions for DNA extraction. Multiplex array (Sequenom®) genotyping for PIK3CA was performed on prePCR amplified DNA. Comparisons were made between high and low grade DCIS using Fisher's exact test.

Results: Among 195 pure DCIS cases, 89 were classified as high grade and 106 as low grade. Sequenom® analysis was informative in all cases. PIK3CA mutations were identified in 4/89 (4%) cases of high grade DCIS and in 24/106 (23%) cases of low grade DCIS (p=0.000). All 4 mutations in high grade DCIS were located in the kinase domain, whereas in low grade DCIS, 9/24 (37%) mutations were in the kinase domain (H1047R) and 15/24 (67%) mutations were in the helical domain (E542K, E545K, N345K).

Conclusion: PI3K mutations were relatively uncommon in pure high grade DCIS as compared to low grade DCIS. PI3K mutations in low grade DCIS were observed in both the kinase and helical domain. These findings support the hypothesis that breast tumorigenesis differs by grade and PI3K mutations may be more prominent in low grade carcinogenesis. The significance of helical domain mutations in low grade lesions requires further investigation.