Abstract PD4-04: Role of breast MRI in predicting pathologically negative nodes after neoadjuvant chemotherapy in cN0 patients in the I-SPY2 trial

Background

In clinically node-negative (cN0) breast cancer patients with triple negative (TN) and HER2+ disease and breast pathological complete response (breast pCR), low rates of nodal positivity after neoadjuvant chemotherapy (NAC) have been demonstrated. In these patients, the omission of surgical axillary staging has been proposed. However, this information is not routinely known preoperatively. We aimed to validate the correlation between pathologic breast response and pathologic nodal status, and evaluate the relationship between response of the breast tumor on MRI and pathologic nodal status after NAC in cN0 patients in the I-SPY2 trial.

Methods

We identified all patients with cT1-4 cN0 breast cancer prior to NAC from graduated arms of the I-SPY2 trial, a prospective neoadjuvant chemotherapy trial. Absence of residual disease post-NAC was defined as longest diameter (LD) of 0 mm on MRI. Breast pCR was defined as the absence of invasive tumor in the breast at surgery. Associations between ypN0 and patient, MRI, and tumor characteristics were assessed using chi-square tests and univariate regression.

Results

Of 365 cT1-4 cN0 patients included, 128 had HR+/HER2- tumors (35%), 60 HR+/HER2+ tumors (16%), 34 HR-/HER2+ tumors (9%) and 143 TN tumors (39%). Overall, 283 patients (78%) were ypN0 after NAC and 152 patients (42%) had a breast pCR. ypN0 rate was higher in patients with a breast pCR than those with residual disease (93% vs 66%, p<0.001). Patients with HR-/HER2+ and TN tumors were more likely to be ypN0 (97% and 87% respectively) than patients with HR+/HER2- and HR+/HER2+ disease (66% and 71% respectively, p<0.001). Other characteristics associated with ypN0 were tumor grade (grade I 57%, grade II 66%, grade III 84%; p=0.002), MammaPrint Classification (High Risk 1 68% and High Risk 2 87%; p<0.001) and absence of residual tumor in the breast on MRI (87% vs 72% in patients with evidence of tumor on MRI post-NAC/pre-surgery; p=0.003).

In patients with HR-/HER2+, HR+/HER2+, HR-/HER2+ or TN disease and a breast pCR, ypN0 rate was respectively 82%, 96%, 96% and 97% (table 1). In patients with HR+/HER2-, HR+/HER2+, HR-/HER2+ or TN disease and with no evidence of residual disease in the breast on MRI, rate of ypN0 was 71%, 80%, 94% and 96% respectively.

Conclusion

In cT1-4 cN0 breast cancer patients with HR+/HER2+, HR-/HER2+ and TN tumors and a breast pCR, ypN0 rates after NAC are extremely high. In patients with HR-/HER2+ and TN tumors with no residual breast disease on MRI after NAC and pre-surgery, ypN0 rates are high enough to consider omission of axillary surgery. In patients with HR+ tumors, MRI is unsufficiently predictive for pathological response and can therefore not be used to select ypN0 patients. Research on the prediction of ypN0 in cN+ I-SPY2 patients is ongoing.

Nodal status in patients with pCR and absence of residual disease on MRI Number of positive nodesBreast Cancer Subtype0123AllBreast pCR     HR+/HER2-27(82)2(6)4(12)033(100)HR+/HER2+24(96)01(4)025(100)HR-/HER2+24(96)1(4)0025(100)TN67(97)2(3)0069(100)Absence of residual disease on MRI     HR+/HER2-24(71)7(21)3(9)034(100)HR+/HER2+16(80)3(15)01(5)20(100)HR-/HER2+15(94)1(6)0016(100)TN54(96)2(4)0056(100)

Citation Format: van der Noordaa ME, Esserman L, Yau C, Mukhtar R, Price E, Hylton N, Abe H, Wolverton D, Crane EP, Ward KA, Nelson M, Niell BL, Oh K, Brandt KR, Bang DH, Ojeda-Fournier H, Eghtedari M, Sheth PA, Bernreuter WK, Umphrey H, Rosen MA, Dogan B, Yang W, Joe B, van 't Veer L, Hirst G, Lancaster R, Wallace A, Alvaredo M, Symmans F, Asare S, Boughey JC, I-SPY2 Consortium. Role of breast MRI in predicting pathologically negative nodes after neoadjuvant chemotherapy in cN0 patients in the I-SPY2 trial [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 PD4-04.

Abstract P2-07-03: Refining neoadjuvant predictors of three year distant metastasis free survival: Integrating volume change as measured by MRI with residual cancer burden

Background: Patients achieving a pathologic complete response (pCR) following neoadjuvant therapy have significantly improved event-free survival relative to those who do not; and pCR is an FDA-accepted endpoint to support accelerated approval of novel agents/combinations in the neoadjuvant treatment of high risk early stage breast cancer. Previous studies have shown that recurrence risk increased with increasing burden of residual disease (as assessed by the RCB index). As well, these studies suggest that patients with minimum residual disease (RCB-I class) also have favorable outcomes (comparable to those achieving a pCR) within high risk tumor subtypes. In this study, we assess whether integrating RCB with MRI functional tumor volume (FTV), which in itself is prognostic, can improve prediction of distant recurrence free survival (DRFS); and identify a subset of patients with minimal residual disease with comparable DRFS as those who achieved a pCR. Imaging tools can then be used to identify the subset that will do well early and guide the timing of surgical therapy.

Method: We performed a pooled analysis of 596 patients from the I-SPY2 TRIAL with RCB, pre-surgical MRI FTV data and known follow-up (median 2.5 years). We first assessed whether FTV predicts residual disease (pCR or pCR/RCB-I) using ROC analysis. We applied a power transformation to normalize the pre-surgical FTV distribution; and assessed its association with DRFS using a bi-variate Cox proportional hazard model adjusting for HR/HER2 subtype. We also fitted a bivariate Cox model of RCB index adjusting for subtype; and assessed whether adding pre-surgical FTV to this model further improves association with DRFS using a likelihood ratio (LR) test. For the Cox modeling, penalized splines approximation of the transformed FTV and RCB index with 2 degrees of freedom was used to allow for non-linear effects of FTV and RCB on DRFS.

Result: Pre-surgical MRI FTV is significantly associated with DRFS (Wald p<0.00001), and more effective at predicting pCR/RCB-I than predicting pCR alone (AUC: 0.72 vs. 0.65). Larger pre-surgical FTV remains associated with worse DRFS adjusting for subtype (Wald p <0.00001). The RCB index is also significantly associated with DRFS adjusting for subtype (Wald p<0.00001). Adding FTV to a model containing RCB and subtype further improves association with DRFS (LR p=0.0007). RCB-I patients have excellent DRFS (94% at 3 years compared to 95% in the pCR group). Efforts are underway to identify an optimal threshold for dichotomizing pre-surgical FTV and FTV change measures for use in combination with pCR/RCB-I class to generate integrated RCB (iRCB) groups as a composite predictor of DRFS.

Conclusion: Pre-surgical MRI FTV is effective at predicting minimal residual disease (RCB0/I) in the I-SPY 2 TRIAL. Despite the association between FTV and RCB, FTV appears to provide independent added prognostic value (to RCB and subtype), suggesting that integrating MRI volume measures and RCB into a composite predictor may improve DRFS prediction.

Citation Format: Hylton NM, Symmans WF, Yau C, Li W, Hatzis C, Isaacs C, Albain KS, Chen Y-Y, Krings G, Wei S, Harada S, Datnow B, Fadare O, Klein M, Pambuccian S, Chen B, Adamson K, Sams S, Mhawech-Fauceglia P, Magliocco A, Feldman M, Rendi M, Sattar H, Zeck J, Ocal I, Tawfik O, Grasso LeBeau L, Sahoo S, Vinh T, Yang S, Adams A, Chien AJ, Ferero-Torres A, Stringer-Reasor E, Wallace A, Boughey JC, Ellis ED, Elias AD, Lang JE, Lu J, Han HS, Clark AS, Korde L, Nanda R, Northfelt DW, Khan QJ, Viscusi RK, Euhus DM, Edmiston KK, Chui SY, Kemmer K, Wood WC, Park JW, Liu MC, Olopade O, Tripathy D, Moulder SL, Rugo HS, Schwab R, Lo S, Helsten T, Beckwith H, Haugen PK, van't Veer LJ, Perlmutter J, Melisko ME, Wilson A, Peterson G, Asare AL, Buxton MB, Paoloni M, Clennell JL, Hirst GL, Singhrao R, Steeg K, Matthews JB, Sanil A, Berry SM, Abe H, Wolverton D, Crane EP, Ward KA, Nelson M, Niell BL, Oh K, Brandt KR, Bang DH, Ojeda-Fournier H, Eghtedari M, Sheth PA, Bernreuter WK, Umphrey H, Rosen MA, Dogan B, Yang W, Joe B, I-SPY 2 TRIAL Consortium, Yee D, Pusztai L, DeMichele A, Asare SM, Berry DA, Esserman LJ. Refining neoadjuvant predictors of three year distant metastasis free survival: Integrating volume change as measured by MRI with residual cancer burden [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 P2-07-03.

Abstract P2-01-01: Impact of California breast density notification law SB 1538 on California women and their health care providers

Purpose: To describe the impact of California Breast Density Notification law (SB 1538) on policy development, policy implementation and supplemental screening strategies within California medical facilities. SB 1538 mandates that breast density information be given to patients but provides no funding for supplemental screening, no guidance on how to triage women for supplemental screening nor which imaging modalities to use.

Methods:

As a result of the law, the California Breast Density Information Group (CBDIG) formed from academic and private practice radiologists and risk assessment experts, reviewing scientific literature and nationally recognized guidelines to provide evidence-based recommendations regarding supplemental screening in women with dense breast tissue. A survey was sent to 6 academic and 3 large private practices in California to record their experience in implementing the law.

Results: CBDIG created a public, institution-neutral, evidence-based website, “breastdensity.info”, that includes information and recommendations regarding supplemental breast screening, with triage for supplemental MRI or US based on breast cancer risk assessment using genetic or family history risk models. CBDIG facilities worked with referring health care providers to inform them of the new law, educated their staff and technologists on implementing policy, and developed notification strategies to comply with legislation.

The survey showed that all 9 facilities recommended supplemental screening based on family history models or genetic testing. 3/9 calculated breast cancer risk in the breast imaging clinic, and 2/9 emailed a risk survey to the patient. 3/9 reported risk in the radiology report, and 1/9 reported risk only if the patient was high risk. Risk assessments were performed by technologists and risk assessment health practitioners. 8/9 facilities estimated breast density by visual methods, and 1/9 by computer. All facilities performed screening breast MRI, 4/9 performed handheld screening US, and 2/9 tomosynthesis. 1/9 obtained tomosynthesis in anticipation of the law, 2/9 are trying to obtain automated whole breast US, and 3/9 are trying to obtain tomosynthesis. Facilities expressed concerns about additional false-positive biopsies produced by supplemental screenings, out-of-pocket expenses for women, and disparities (low income) in notified populations.

Conclusion: SB 1538 resulted in the formation of the CBDIG and the website, “breastdensity.info”. Our survey showed variations in imaging modalities available and policy implementation at each facility. Given that several states currently have breast density laws or have laws that will become effective in the near future, it is important for breast imagers and clinicians to be informed of the current literature, realize the variation in equipment and policies at various facilities, and develop recommendation strategies to guide patients seeking supplemental screening. We plan to follow up this survey with a larger survey of the Society of Breast Imagers at a later date.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-01-01.

Abstract P4-04-15: UC San Diego molecular tumor board: Experience in breast cancer

Background: To realize the promise of personalized medicine, it is important to build the infrastructure to match patients to the most promising therapies using evolving genomic information to inform clinical trial and treatment recommendations.

Methods: A molecular tumor board was established in December 2012 consisting of representatives of medical oncology, surgery, radiation, pathology, radiology, clinical genetics, molecular genetics and diagnostics, basic and translational science, and bioinformatics and pathway analysis. Patients with metastatic breast cancer signed consent for collection of data in a registry format related to clinical history, genomic analysis, treatment recommendations, and response. Tumor specimens from patients with metastatic breast cancer were subjected to a next generation sequencing diagnostic test (Foundation One™) in a CLIA-certified lab (Foundation Medicine) and analyzed for genomic alterations in a 182 gene panel or a 236 gene panel. Clinical cases and genomic alterations were discussed at Molecular Tumor Board where clinical trials and treatment recommendations were considered, with the final decision made by the treating oncologist.

Results: Genomic analyses of metastatic breast cancer specimens from 17 consented patients had at least one genomic alteration and no tumors had the same genomic alterations. 12/17 had ≥ 2 and 4/17 had 6 or 7 genomic alterations. The most common genomic alterations were in PIK3CA observed in tumors from 6/17 patients. 1/17 tumor specimens had only a single genomic alteration for which there are no current targeted drugs in clinical studies or available commercially (GATA3). Radiographic and/or tumor marker response have been observed to date in 3/4 heavily pretreated patients following treatment with a targeted therapy or a targeted therapy informed by the genomic data in combination with other drugs.

Conclusions: The strategy of matching targeted clinical trial and commercially available therapies to genomic alterations of tumor specimens from individual patients with metastatic breast cancer may offer promise to patients with advanced refractory disease. Biopsies of metastatic disease, genomic analysis in CLIA labs, establishment of molecular tumor boards, definition of “matched” versus “non-matched” therapies, capturing data in a registry to create a learning environment, and most importantly, availability of targeted therapies in clinical trials or commercially, are required for this individual patient strategy to inform current and future treatment options for much larger patient populations.

Funding from UC San Diego Moores Cancer Center MyAnswerToCancer philanthropic fund.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-04-15.

Abstract P2-01-06: How much agreement can we expect on BI-RADS mammographic findings? Observer agreement among 10 expert mammographers

Purpose: To determine the agreement between expert readers on mammographic findings and calcification patterns.

Materials and Methods: Ten academic radiologists from 5 centers reviewed 250 de-identified mammographic cases without prior exams which were previously assessed as BI-RADS 4 or 5 with subsequent pathologic diagnosis by percutaneous or surgical biopsy. For benign cases diagnosed by percutaneous biopsy, 1 year of benign or negative imaging follow-up was required. Using standardized forms, each radiologist assessed the presence of any suspicious mammographic findings (microcalcifications, asymmetry (1-vew), focal asymmetry (2-view), architectural distortion), and the morphology (none, round/punctate, amorphous, coarse heterogeneous, fine pleomorphic, fine linear branching) and distribution (none, diffuse, regional, grouped, linear, segmental) of any identified microcalcifications. Agreement between radiologists for presence/absence of findings, morphology, and distribution of calcifications was determined by calculating the Kappa (k) coefficient with 95% confidence interval (95% CI). The kappa coefficient proposed strength of agreement is ≤0 = poor, .01-.20 = slight, .21-.40 = fair, .41-.60 = moderate, .61-.80 = substantial, and .81-1 = almost perfect, as established by Landis and Koch.1

Results: Of the 250 lesions, 156 (62%) were benign and 94 (38%) malignant. Agreement among the 10 expert readers was strongest for recognizing the presence/absence of calcifications (k = 0.82, 95% CI: 0.80-84), “almost perfect”). There was substantial agreement among the readers for the identification of a mass (k = 0.67, 95% CI: 0.66-69), whereas agreement was fair for the presence of a focal (2-view) asymmetry (k = 0.21, 95% CI: 0.1900.23) or architectural distortion (k = 0.28, 95%CI: 0.26-0.30). Agreement for asymmetries (1-view) was slight (k = 0.09, 95%CI: 0.08-0.11). Among the 6 categories of microcalcification distribution and morphology, reader agreement was moderate (distribution k = 0.60, 95%CI:0.59-0.61; morphology k = 0.51, 95%CI: 0.50-0.52).

Conclusion: When asked to characterize suspicious mammographic findings, this sampling of 10 expert academic breast imagers across 5 centers revealed varying strength of agreement for different findings, ranging from slight to almost perfect. Strongest agreement (“almost perfect”) was found for identifying the presence or absence of microcalcifications, although agreement drops to moderate when readers are asked to specify microcalcification morphology and distribution.

1 Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics.1977;33:159-174.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-01-06.

OT2-04-02: Metformin for Breast Cancer Prevention: A Pilot Study

Background

There is a body of accumulating evidence connecting metformin, a biguanide derivative which reduces hepatic gluconeogensis and improves skeletal muscle insulin sensitivity, to reduced breast cancer risk. This, in addition to a well established drug safety record among diabetics and non-diabetics, has provoked an interest in further study of metformin's effects on breast cancer risk indicators. In our study, we examine the effects of metformin on breast density and proliferative cell marker Ki67, both indicators of breast cancer risk. This is a small observational pilot study to determine the feasibility of subject recruitment, data collection through fine-needle aspiration, and breast density measurement.

Trial Design: Recruitment of 10 breast surgery patients with high risk histology to: 1. Undergo peri-areolar fine needle aspiration (RPFNA) used to collect breast cells for analysis of proliferative marker Ki67. 2. Breast density assessment by a) mammography (the standard method) and b) whole-breast ultrasound (an innovative method recently developed at UCSD).

Each subject will undergo a single view mammogram, whole-breast ultrasound, and intra-operative RPFNA. No drug or therapeutic intervention will take place in this pilot study.

Eligibility: Female undergoing excisional high risk breast surgery.

Specific Aims: Aim 1. To determine the feasibility of recruiting high risk breast surgery patients to an observational study involving RPFNA, mammography, and whole-breast ultrasound.

Aim 2. a) To compare mammography and whole-breast ultrasound for measurement of breast density. b) To examine potential for detecting biomarkers of cell proliferation through RPFNA.

Statistical Method: Breast density will be determined by the ratio of fibroglandular tissue to fat measured on mammogram and WBU. Cell proliferation will be assessed by the percentage of positivity for biomarker Ki67 in breast ductal cells.

Accrual and target accrual: Five of ten breast excisional high risk breast surgery subjects have been accrued at this time.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT2-04-02.

Training overweight/obese older women at high risk for breast cancer to use web-based weight loss tools: The HELP pilot study

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Background: Excess weight is one of the few modifiable risk factors for incident breast cancer. Many programs can achieve a 7% weight loss but few can maintain it over time. Training women to use self-help resources over the internet has potential for reducing intervention costs and ensuring program maintenance.

Methods: 50 overweight/obese (BMI≥27.5 kg/m2) women at increased risk of breast cancer (Gail score≥1.7) were identified from a mammography registry and enrolled in the HELP pilot study and randomized with 2:1 probability to a 12-week lifestyle intervention or a comparison group. Twelve telephone-based coaching calls trained participants to use a free, publicly available website to set goals and track performance for dietary intake and physical activity. The comparison group received information but no training. At baseline and 12 weeks, participants were weighed, fitted with an accelerometer for physical activity pattern, and completed questionnaires.

Results: At baseline, participants were 60.9±0.79 years of age with a BMI of 33.1±0.60 kg/m2; 39% were daily internet users. Thirty-three were randomized to the intervention group with 91% completing follow-up. Fifty-four percent were able to use the website reliably and found it to be helpful, including 44% of previously nondaily internet users. At 12 weeks, intervention group participants who found the website helpful had lost 5.6±0.7 kg, or 6.7% of initial weight, intervention participants who did not find it helpful lost 0.8±0.9kg or 1.1% of initial weight and the comparison group gained 1.0±0.94 kg (89% follow-up) The between-group difference weight change was 4.2 kg (p<.0001). 74% of intervention group participants lost weight, compared to only 34% of women assigned to the comparison group.

Conclusions: A 12-session telephone coaching program to train women to use publicly available web-based weight loss programs effectively achieved a large short-term weight loss among the majority of participants. Further follow-up is needed to identify how well the initial weight loss is maintained without further intervention assistance.

Creating a realistic breast: the nipple-areola reconstruction

Breast reconstruction is a multi-stage process, leaving many patients overwhelmed by the surgeries they have had to endure by the time they reach the final stages. Patients, however, are encouraged to complete their new breast by undergoing nipple and areolar reconstruction. These last two procedures improve the aesthetic result by transforming the surgically created breast mount into a more natural-appearing breast. This final touch enhances body image, restoring the patient's feeling of wholeness. These procedures are mostly done in the office under local or no anesthesia, depending on the sensation present in the reconstructed breast.