Abstract P6-16-04: A self-administered geriatric assessment tool for Spanish-speaking older women with breast cancer

Background: Almost a quarter of older adults in the United States will identify themselves as Hispanic/Latino by 2060. Our group has previously developed and validated a self-administered geriatric assessment tool which can be used to identify functional, psychological, social and cognitive impairments among older patients with various types of cancer. Among English-speaking older adults, completing this tool using paper/pencil or a tablet takes a median of 15-21 minutes (min), with < 10% needing assistance to answer it (Hurria, JOP 2016). However, the utilization of this tool among Spanish-speaking older adults has not been tested. We assessed the feasibility of administering a translated and validated Spanish version of our geriatric assessment tool for older Hispanic women with breast cancer, and identified their preferred format (tablet or paper/pencil).

Methods: Spanish-speaking women aged ≥ 65 years with a diagnosis of breast cancer completed the geriatric assessment twice on the same day. Patients were randomized into 3 groups: paper/pencil twice; tablet and paper/pencil in random order; and tablet twice. We assessed the proportion of patients requiring assistance to complete the geriatric assessment, the time needed to complete it, and the proportion of patients who thought the geriatric assessment was difficult/very difficult.

Results: 140 older women with breast cancer completed the geriatric assessment twice and were evaluable. Mean age was 71.6 years (SD 5.8), 53% had ≤ 8th grade education, 43% were married, 45% were retired, 32% were homemakers, and 6% were employed. The participants came from 13 different Spanish-speaking countries, although 70% were born in Mexico. For 90%, Spanish was their primary language, and 75% spoke only in Spanish at home. Regarding computer skills, 64% of the patients said they had none. 39% (n = 54) were unable to complete the geriatric assessment on their own; mean time to complete the geriatric assessment was 29 min (range 8-90); and 28% (n = 39) thought the geriatric assessment was difficult/very difficult. The most common reasons for needing assistance were difficulty understanding questions (39%) and visual problems (31%). Patients with ≤ 8th grade education took longer to complete the geriatric assessment (mean 37.2 vs 29.4 min, p < 0.01), and more often needed help completing the assessment (51% vs 19%, p < 0.01) than those with ≥9th grade education. 53% of the participants preferred using a tablet to answer the geriatric assessment, while 47% preferred paper/pencil.

Conclusions: A substantial proportion of Spanish-speaking older women with breast cancer required assistance to complete our self-administered geriatric assessment tool. This may be a consequence of the low educational level we found among this patient population. Tailoring assessments for diverse populations with particular attention to educational level is needed in multicultural settings.

Citation Format: Soto-Perez-de-Celis E, Vazquez J, Kim H, Sun C-L, Somlo G, Yuan Y, Waisman JR, Mortimer JE, Kruper L, Taylor L, Patel NH, Moreno J, Charles K, Roberts E, Uranga C, Levi A, Katheria V, Paredero-Perez I, Mitani D, Hurria A. A self-administered geriatric assessment tool for Spanish-speaking older women with breast cancer [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 P6-16-04.

Abstract P6-17-18: Pathologic complete response (pCR) in locally advanced HER2+ (HER2+) breast cancer (BC) treated with anthracycline-free neoadjuvant therapy

Background: Response to neoadjuvant therapy is a predictor of progression-free and overall survival in HER2+. To decrease treatment associated toxicities in patients with HER2+ breast cancers we utilized a non-anthracycline regimen with pertuzumab (pert), trastuzumab (trast), and nab-paclitaxel (nab). Pre- neoadjuvant therapy biopsies were procured to evaluated possible biological predictors of pathologic complete response (pCR).

Methods: Women with locally advanced HER2 positive breast cancers were recruited from our breast cancer clinics. After obtaining informed consent for this IRB-approved trial, patients were treated with 6 cycles of pertuzumab (day 1 every 21 days [d]), and weekly trastuzumab 2 mg/kg with and nab-paclitaxel 100 mg/m2. Formalin fixed paraffin embedded (FFPE) or frozen biopsies pre-NT and post-NT were collected, along with blood samples at pre-treatment, and at the end of study for correlative analysis.

Results: Accrual is complete, with 42 of the 45 HER2+ patients assessed for pCR rate (3 too early to evaluate). The median age was 54 yrs (range 31-77 years). 12 patients were stage 3, 26 stage 2, and 1 stage 1 patient. The pCR rate was 64.2% (27/42), with 73.7% (14/19) in ER/PR negative patients and 56.5% (13/23) in ER/PR positive patients. The initial primary tumor size was similar for in those who achieved pCR and non-pCR patients (mean 4.1 cm vs 3.2 cm, respectively). Most patients required dose modifications. Grade 3 AEs reported included 6 patients with hypertension, 3 patients with hematological AEs, 3 patients with elevated LFTs, and 2 patients with diarrhea.

Conclusions: This anthracycline-free regimen in HER2+ BC can achieve promising pCR response rates, with toxicities well-managed with dose modifications. Results of correlative analysis will be presented.

Citation Format: Somlo G, Waisman J, Yuan Y, Kruper L, Frankel P, Jones V, Lusi T, Schmolze D, Yim J, Hurria A, Mortimer J. Pathologic complete response (pCR) in locally advanced HER2+ (HER2+) breast cancer (BC) treated with anthracycline-free neoadjuvant therapy [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 P6-17-18.

Abstract P1-15-07: Phase II trial of neoadjuvant carboplatin and nab-paclitaxel in patients with locally advanced triple negative breast cancer

Background: Response to neoadjuvant therapy (NT) predicts progression-free and overall survival in triple negative breast cancer (TNBC). Carboplatin has shown efficacy in patients with TNBC. The current phase II prospective neoadjuvant trial was designed to decrease toxicities and improve efficacy.

Methods: Patients with TNBC received carboplatin (carb) and nab-paclitaxel (nab). Pre-NT biopsies were procured to evaluate for biological predictors of pathological complete response (pCR). Newly diagnosed stage II-III patients with TNBC were treated with 4 cycles of carb (AUC 6, day 1 of 28 day cycle) and weekly nab 100 mg/m2 x 16. Targeted accrual goal is 70. RNA extracted from formalin fixed paraffin embedded (FFPE) biopsies pre-NT was tested for MammaPrint/BluePrint and custom Agilent full genome microarrays for gene expression (GE, by Agendia Inc). The raw gMeanSignal was log2 transformed and normalized to the 75thpercentile for GE analysis. Association between MammaPrint/ BluePrint results and pCR was tested by Fisher exact test. The linear model from R limma package was applied. Ingenuity Pathway Analysis (IPA) was applied to assess functional pathways associated with pCR. Cellular distribution by CIBERSORT analysis was carried out to estimate the abundance of 22 different cell types in each patient sample, and test whether the distribution of cell types is different between pCR and non-responders.

Results: A total of 64 patients were enrolled. Two patients were deemed ineligible (Her2+), and three were too early, resulting in 59 patients evaluable for pathological response. The pCR rate was 47% (RCB0, 28/59). Eight patients had RCB I. RCB0 plus RCBI reached 61%. Sufficient quality RNA and DNA were available from the first 43 of 55 pts with TNBC. 44/59 (75%) required dose modifications (mostly hematologic), 5 patients had grade 3 peripheral neuropathy (PN), 3 had grade 2 PN, and 3 patients had grade 2 LFTs. In the 53 pts with GE assessment, pCR was inversely associated with luminal BluePrint type (p=0.04). With fold change >1.5 and p-value < 0.05, 36 genes were differentially expressed (DE) in TNBC. CIBERSORT analysis suggested that T-cell regulatory cells (TREGS) were associated with pCR in TNBC, and 5 cell types (plasma cells, TREGS, macrophage, dendritic cells and neutrophils) presented differently between all pCR and non-pCRs with P-value <0.05. TDP analysis to assess correlation with pCR is ongoing.

Conclusions: The combination of carboplatin and nab-paclitaxel given in the neoadjuvant setting reached a promising pCR rate of 47%. The MammaPrint non-luminal BluePrint subtype was predictive of pCR in TNBC. Preliminary analysis suggested that a 36-gene signature for TNBC was associated with pCR. CIBERSORT analysis revealed 5 cell types with different abundance between the pCR and non-responders, suggesting the need to target the tumor microenvironment.

Citation Format: Yuan Y, Frankel P, Li M, Kruper L, Jones V, Treece T, Waisman J, Yim J, Tumyan L, Schmolze D, Hurria A, Yeon C, Mortimer J, Somlo G. Phase II trial of neoadjuvant carboplatin and nab-paclitaxel in patients with locally advanced triple negative breast cancer [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 P1-15-07.

Abstract P6-15-07: Not presented

This abstract was not presented at the symposium.

Abstract P5-22-12: Oncological safety of nipple-areola sparing mastectomy in comparison with skin sparing and total mastectomy: Results from a NCI-designated comprehensive cancer center

Nipple-areola sparing mastectomy (NSM) may be offered to some women with breast cancer as an alternative to skin sparing (SSM) or total mastectomy (TM) with excellent cosmetic results and acceptable recurrence risk. The aim of this study is to determine the local/regional recurrence rate of NSM in comparison to SSM and TM at our institution and to determine the factors that may be associated with risk of recurrence. Women who underwent NSM (n=148), SSM (n=660) or TM (n=443) at City of Hope National Medical Center between May 2007 and December 2014 for Stage 0-III breast cancer were identified retrospectively. Exclusions were: women with inflammatory breast cancer and those who had mastectomy for recurrent breast cancer. Overall survival (OS) and disease free survival (DFS) were analyzed using Cox regression controlling for age, race/ethnicity, stage, histology, grade, hormone receptor and Her2 receptor status. There were total of 165 NSMs, 704 SSMs and 466 TMs performed for cancer, accounting for the patients with bilateral cancers. The median follow up time was 38, 58 and 55 months for NSM, SSM and TM, respectively. Median (range) age at diagnosis was 49 (23-74) for NSM, 51 (23-90) for SSM and 59 (26-92) for TM. In the NSM group, 76% of patients had invasive ductal cancer (IDC) and 15% had ductal carcinoma in-situ (DCIS); this was comparable to 73% and 13% in the SSM group and 78% and 9% in the TM group, respectively. The majority of patients who underwent NSM had Stage II disease (45%), which was similar to SSM (43%) and TM (44%). Only 3% of NSM patients had Stage III disease compared to 17% of SSM patients and 29% of TM patients. Most of the patients in all 3 surgical groups received adjuvant chemotherapy (NSM 59%; SSM 52%; TM 51%). Of patients who underwent NSM, 20% received neoadjuvant chemotherapy, compared with 29% of SSM patients and 35% of TM patients. The local/regional recurrence rate per breast was 12/165 (7.3%) for NSM, 23/704 (3.3%) for SSM and 11/466 (2.4%) for TM (n=11). Median time to recurrence was 20, 26 and 16 months for NSM, SSM and TM, respectively. Of the NSMs performed only 1 recurrence occurred at the nipple-areolar complex (0.6%), 9 recurrences were at the chest wall (5.5%) and 2 were at the axilla (1.2%). Eight recurrences after NSM had DCIS in addition to IDC at the time of initial diagnosis while 2 had pure DCIS, 1 had pure IDC and 1 had invasive lobular cancer. There were 8 recurrences with estrogen receptor (ER) and progesterone receptor (PR) positivity at the time of initial diagnosis, that converted to ER+, PR-. One third of recurrences after NSM had multifocal disease. There was no significant difference found in adjusted overall survival (p=0.49) and adjusted disease free survival (p=0.10) among NSM, SSM and TM patients. Even though there is higher rate of local/regional recurrence with NSM, there is no difference in overall and disease-free survival at our institution. Presence of DCIS may be an important factor for recurrence. From these data we conclude that NSM is an oncologically acceptable alternative to SSM and TM, with excellent cosmetic results.

Citation Format: Bostanci Z, Wang X, Ottesen R, Nikowitz J, Jones VC, Springer L, Lai L, Taylor L, Vito CA, Paz IB, Niland J, Kruper L, Yim JH. Oncological safety of nipple-areola sparing mastectomy in comparison with skin sparing and total mastectomy: Results from a NCI-designated comprehensive cancer 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 P5-22-12.

Abstract P4-21-35: Phase II trial of pertuzumab, trastuzumab, and nab-paclitaxel in patients (pts) with HER2 overexpressing (HER2+) locally advanced or inflammatory breast cancer (LABC) or untreated stage IV metastatic breast cancer (MBC)

Background: Pathologic complete response (pCR) to HER2-targeting neoadjuvant therapy (NT) predicts for improved survival (Cortazar et al, Lancet, 2014). The addition of pertuzumab to trastuzumab and docetaxel increased pCR rates, and, as first line treatment for MBC led to longer overall survival ([OS] Swain et al, NEJM 2015). Avoidance of anthracyclines in the adjuvant setting for HER2+ BC reduced the risk of secondary hematologic malignancies without a detriment to OS (Slamon et al, NEJM, 20111). Finally, nab-paclitaxel (nab) might provide an advantage over other taxanes via decreased use of steroids and may lead to increased response rates (RR). We designed a study of pertuzumab (pert), trastuzumab (trast), and nab, testing the feasibility and efficacy of this regimen in the LABC and metastatic breast cancer settings.

Materials and Methods: Pts with Stages II-III LABC received six cycles of NT with pert (day 1 q 21 days), trast, and nab 100 mg/m2 (both given IV, weekly). Pts with untreated MBC received the same regimen until progression, toxicities, or patient or physician preference led to stopping therapy. Primary endpoints included pCR (LABC) and RR and progression-free survival (PFS) in MBC. Forty pts with LABC and 25 pts with MBC were to be accrued. The study was designed to test whether the pCR rate of Neosphere (Gianni et al, Lancet Oncol, 2012, > 45.8%) and the PFS rate of CLEOPATRA (median of > 18.5 months) can be matched or exceeded. Procurement of serial samples for assessment of tumor gene expression, circulating tumor cells, miRNA, and serum DNA profiling for exploratory biomarker analysis was carried out.

Results:Twenty-two of 28 already enrolled pts with LABC (clinical stage II:15, stage III: 7) completed NT. The median age was 53 (34-77). The pCR rate was 86% (6/7) for hormone receptor negative (HR-) and 40% (6/15) for HR+ pts, with an overall pCR of 55%. Three pts without pCR following NT had residual BC with a HER2 negative phenotype. Eighteen of 22 pts required nab dose modifications. The most frequent toxicities following NT included elevated liver function tests:27%, peripheral neuropathy:23%, hematological toxicities:17%, diarrhea:18%, infusion reactions:18%. In the MBC cohort there were 13 of 16 enrolled pts with > 2 months of follow-up. The median age was 47 (31-65), 62% had HR+ disease. A CR rate of 4/13 (31%) and confirmed RR of 77% were observed. The median number of cycles with pert, trast, nab was 9 (3+ to 41); 11 of 13 pts required dose modifications or delays (3 of the delays were due to primary breast surgery performed upon response to treatment). At a median follow-up of 19 months, PFS and OS estimates are 63% (95% CI 0.09-0.93), and 89% (95% CI 0.61-1.0).

Conclusion: The non-anthracycline-containing regimen of pertuzumab, trastuzumab, and nab-paclitaxel induced a high pCR rate in HER2+ BC. PFS is encouraging in MBC. Outcome of the fully accrued cohorts inclusive of residual cancer burden scores in the LABC cohort, and correlative data with exploratory biomarker analysis will be presented.

Citation Format: Somlo G, Frankel P, Yeon C, Yuan Y, Yim J, Kruper L, Taylor L, Mortimer J, Waisman J, Jones V, Vito C, Paz B, Huria A, Li D, Gaal C, Tong T, Tumyan L. Phase II trial of pertuzumab, trastuzumab, and nab-paclitaxel in patients (pts) with HER2 overexpressing (HER2+) locally advanced or inflammatory breast cancer (LABC) or untreated stage IV metastatic breast cancer (MBC) [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 P4-21-35.

Abstract P1-10-19: Skin, and nail, infections associated with the addition of pertuzumab to trastuzumab-based chemotherapy

Objectives: We have maintained a local registry of skin and nail infections in patients receiving pertuzumab and trastuzumab as treatment for HER2 positive breast cancer. Over the past 16 months, we have continued to observe an increase in infectious complications in patients receiving the combination of pertuzumab and trastuzumab with or without chemotherapy. We expand a series of prospectively identified patients who developed infections while on these regimens. Methods: We became concerned about an increased incidence of infections shortly after the FDA approval of pertuzumab, and created an IRB approved registry of these patients. Results: Twenty-eight women were identified to have 32 separate infections (often at more than one site); 9 after cycle 1; 6 after cycle 2, 9 after cycle 3 and 8 after 4 or more cycles. The median age was 51 (Range 25-67); 14 received pertuzumab, trastuzumab, carboplatin, and docetaxel (PTCH), 5 pertuzumab, trastuzumab, and docetaxel, 7 pertuzumab, trastuzumab, and nab-paclitaxel, and 2 pertuzumab and trastuzumab. Folliculitis of the scalp, abdomen, and/or buttocks was observed in 19 patients, abscesses in 8 patients (4 of whom required incision and drainage) and cellulitis in 2. Severe paronychial infections involving one to 16 digits were observed in 4; 2 pt required surgical removal of 2 nails. Quantitative immunoglobulins were found to be low in 8 of 17 women tested; 2 patient had low total protein but did not have an assessment of quantitative immunoglobulins. All patients were initially treated with oral antibiotics, and 6 required hospitalization. Cultures were obtained in 10 patients; Staphylococcus aureus was identified in 4, methicillin resistant Staphylococcus aureus (MRSA) in 5, Enterococcus faecalis in 1. A 57 year old pt receiving neoadjuvant PTCH died on cycle 2 day 7. Autopsy was consistent with sepsis and gram positive cocci were identified. A 62 year old became septic and developed renal failure. Skin biopsies were performed in 3 patients and are consistent with changes associated with EGFR inhibition.

Conclusions: We believe these infections are a result of combining pertuzumab with trastuzumab as 2 pts received no concurrent chemotherapy. An awareness of this complication is critical as some infections may be life-threatening. We have initiated patient education to ensure awareness of this potential complication.

Citation Format: Mortimer JE, Yuan Y, Jung J, Kruper L, Stewart D, Chung S, Yu WK, Mendelsohn M, D'Apuzzo M, Tegtmeier B, Dadwal S. Skin, and nail, infections associated with the addition of pertuzumab to trastuzumab-based chemotherapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-19.

Abstract P1-14-10: Phase II trial of neoadjuvant chemotherapy with carboplatin and nab-paclitaxel in patients with triple negative locally advanced and inflammatory breast cancer

Background: Pathologic complete response (pCR) and residual cancer burden (RCB scores of 0 [pCR] or 1[near CR]) after neoadjuvant chemotherapy (NCT) may predict for improved survival (Symmans et al. J Clin Oncol 25:4414-22, 2007). We set out to test the pCR rate with an anthracycline-free regimen of carboplatin (carb) and nab-paclitaxel (nab) in patients (pts) with triple negative breast cancer (TNBC).

Materials and Methods: Forty-nine pts with stages II-III BC were to receive carb (AUC 6) on day 1 of a 28 day cycle, and nab 80 mg/m2 weekly, for a total of 4 cycles. Core biopsies were performed prior to NCT. Blood procurement for circulating tumor cell (CTC) analysis using the CellSearch platform was carried out pre-treatment, mid-treatment, and at surgery. We set out to assess the predictive value of Mammaprint (poor vs. good), BluePrint (basal, vs. luminal, vs. HER2) molecular subtype as well as microarray RNA and miRNA profiling, for pCR. Responses were also dichotomized as complete or near complete response (Symmans RCB scores of 0-1) vs. suboptimal response (RCB score > 1).

Results: The median age was 53 (28-75). Pts presented with clinical stages II (63%) and III (37%). So far, 38 of the 49 pts accrued between 2/2012 and 6/2015, have undergone surgery, 68% of whom underwent modified radical mastectomy. The pCR rate (breast and lymph nodes in CR) was 53%, and RCB 0 and 1 were seen in 68% of pts. Toxicites included grade ¾ anemia (45%), thrombocytopenia (13%) and neutropenia (53%,1 pt with neutropenic fever). Dose adjustments were needed in over 80% of pts. Grades 2 or 3 peripheral neuropathy were seen in 8% each, and grades 3-4 fatigue (13%), hypokalemia (3%), and hyponatremia (3%) were observed. The median number of CTCs (pre-NCT) observed in 7 CTC positive pts of the first 27 pts who completed surgery was 1 (0-7), and 2 of the 7 pts continued to have CTCs at the time of surgery (1 CTC each), while 2 pts without CTCs pre-NCT had CTCs (1 each) detected at surgery. The final pt enrolled is expected to complete surgery by 10/2015. Results of sequential CTC assessments, MammaPrint/Blueprint and RNA/miRNA analysis of pre- and post-treatment specimens and their correlation with pCR will be presented.

Conclusion: The non-anthracycline-containing regimen of carb and nab-paclitaxel induced a high pCR rate in TNBC, in preliminary analysis. Ongoing profiling may allow for future subset-specific modification of this regimen to increase pCR across all molecular subtypes of TNBC.

Citation Format: Somlo G, Chung S, Frankel P, Hurria A, Koehler S, Kruper L, Mortimer JE, Paz B, Robinson K, Taylor L, Vito C, Waisman J, Yeon C, Yim J, Yuan Y, Tong T. Phase II trial of neoadjuvant chemotherapy with carboplatin and nab-paclitaxel in patients with triple negative locally advanced and inflammatory breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-14-10.

Abstract P3-03-02: Identification of molecular pathways to define the intake rate of patient-derived hormone receptor positive (HR+) breast cancer xenografts (PDXs) in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice

Background and Purpose: Despite recent progress in our endocrine therapy of hormone receptor positive (HR+) breast cancers, a significant number of patients with primary breast cancer continue to relapse, and those with stage IV disease face a median overall survival of ∼ 3.5 years. Primary or acquired resistance to anti-estrogen-based therapies is an overarching challenge. To guide our treatment selection, there is an essential need to improve our understanding of the biology of HR+ breast tumors responsive to and those resist to anti-estrogens or aromatase inhibitors (AIs). The application of patient-derived xenografts (PDXs) in preclinical studies has begun to open the door to mimicking human disease on the research bench. However, HR+ breast cancer PDXs are difficult to establish. Although preclinical data from DeRose et al [Nat. Med. 2011: 17:1514-1520] indicate that the rate of engraftment serves as an independent predictor for poor outcome, the question which has not yet been adequately addressed is: "why some tumors can grow in mice, and some don't, even when their clinical, pathological stage and subtype (i.e. ER positivity) are same?" Here, we hypothesize that the molecular characteristics of patient HR+ tumors are key determinants to the tumor intake rate in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice. Hence, reverse phase protein array (RPPA) analysis has be performed using human patient tumors to identify driver-pathways that impact tumor intake in NSG mice.

Results and Discussion: We compared the protein expression profile of six HR+ patient tumors (four HR+ and two HR+ HER2+), which were successfully engrafted into NSG mice and established as PDX models, with the patient tumors which we were unable to establish as PDX. Of 90 patient HR+ tumors which failed to transplant, 21 tumors were picked to match the tumor type (all of them were invasive ductal carcinoma or its metastases), clinical stage and pathological grade of engrafted tumors [Table 1]. In addition to patient tumors, six established HR+ PDXs were also submitted for analysis. Quantified expressions of 272 cancer-related proteins and phospho-proteins by RPPA have been performed on these specimens. Pathways identified as predictors of intake rate of PDXs in NSG mice, and tissues from paired PDX from mice with different passages, will be evaluated for the protein expression changes to elucidate the passage effects and generate therapeutic models based on protein expression and tumor growth.

Table 1. Characteristics of the patient tumors which were successfully established as PDX modelsERPgRHER2AgePatient ethnicityClinical stageNottingham histologic scoreSource++-63Hispanic3IIIBreast tumor+--71Hispanic2IIIBreast tumor+--52African-american4N/ABrain mets+--63Caucasian4N/AChest wall mets+-+34Caucasian2IIBreast tumor+++72Caucasian4IIIChest wall metsmets: metastases

Citation Format: Kanaya N, Somlo G, Wu J, Frankel P, Wu SV, Nguyen D, Kai M, Chan N, Meng-Yin H, Kirschenbaum M, Kruper L, Vito C, Yuan Y, Hurria A, Mortimer J, Chen S. Identification of molecular pathways to define the intake rate of patient-derived hormone receptor positive (HR+) breast cancer xenografts (PDXs) in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-03-02.

Abstract PD08-02: Disparities in the Utilization of Reconstruction after Mastectomy: The California Teachers Study

Background: For breast cancer patients undergoing mastectomy, factors such as insurance status, race/ethnicity, age, and type of hospital influence whether post-mastectomy reconstruction (PMR) is performed. This study was undertaken to determine if additional patient variables and clinicopathologic features also influence the utilization of PMR using the California Teachers Study (CTS).

Methods: Patients were identified from the CTS, a cohort of approximately 133,000 female public school teachers and administrators, followed prospectively from 1995 forward to investigate exposures associated with incident cancer and other outcomes. All in situ and invasive breast cancers were identified through linkage with the California Cancer Registry, as well as with the California Office of Statewide Health Planning and Development (OSHPD) hospital discharge database to determine the rates of mastectomy with and without reconstruction. Patterns in PMR rates were examined by calendar year, age, race/ethnicity, type of insurance, type of hospital, tumor stage, body mass index (BMI), family history of breast cancer (FH), smoking history, physical activity, and prior breast implant status using a chi-square test. Univariable and multivariable-adjusted odds ratios (OR) with 95% confidence intervals (CI) were estimated for relative odds of immediate reconstruction vs. mastectomy only.

Results: During follow-up, 1,253 CTS participants with incident breast cancer underwent mastectomy with (N = 368) and without (N = 885) reconstruction. In multivariable stepwise logistic regression analyses, calendar year, age, type of insurance, tumor stage, and prior breast implant were statistically significantly associated with use of reconstruction. The proportion of patients undergoing immediate PMR increased from 21.8% during 1995–1999 to 26.4% during 2005–2009. A statistically significant dose-response was apparent between older age at surgery and decreased likelihood of post-mastectomy reconstruction (Ptrend<0.001). Race/ethnicity was not significantly associated with the use of PMR because the majority of patients were non-Hispanic white (89.5%). Most participants either had private insurance (56.8%) or Medicare (42.4%); those with private insurance were twice as likely to undergo PMR compared to patients with Medicare (OR 2.23: 95%CI 1.25–4.00, p = 0.01). Compared to participants with in situ and stage I breast cancer combined, participants with stage II or stage III breast cancer had one-third to one-half lower odds of postmastectomy reconstruction relative to mastectomy only (ORstageII = 0.67, 95% CI = 0.49–0.90, p = 0.01; ORstageIII=0.47, 95% CI=0.29–0.77, p = 0.002). Participants with a prior history of a breast implant were 7 times more likely to undergo PMR than participants with no such history (OR 7.14: 95%CI 2.38–21.41, p < 0.001).

Conclusions: In the CTS population, having a prior breast implant and lower tumor stage were additional variables associated with increased odds of PMR. This study validates previous studies which have shown that private insurance and younger age are associated with the use of reconstruction after mastectomy. Patient and health care provider education is warranted to ensure that all patients undergoing mastectomy are offered and have access to PMR.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD08-02.

Basal-, Luminal-, and HER2- Molecular Subtype, and the MammaPrint 70-Gene Signature as Predictors of Response to Neoadjuvant Chemotherapy (NCT) with Docetaxel, Doxorubicin, Cyclophosphamide (TAC), or AC and Nab-Paclitaxel and Carboplatin +/- Trastuzumab in Patients (Pts) with Stage II-III and Inflammatory Breast Cancer (BC)

Background: Pathologic complete response (pCR) and minimal residual cancer burden (RCB scores of 0 [pCR]-1[near CR]) after NCT may predict for improved survival (Symmans et al. J Clin Oncol 25:4414-22, 2007). Hence, improved NCT regimens in conjunction with molecular markers that predict for both response and/or resistance are needed. Materials and Methods: 115 pts with stages II-III BC were to be prospectively randomized to receive 6 cycles of docetaxel 75 mg/m2, doxorubicin 50 mg/m2, cyclophosphamide 500 mg/m2 with filgrastim support (TAC, arm A) versus a novel regimen of A 60 mg/m2 and C 600 mg/m2 given every 2 weeks x 4, followed by 3 weekly doses of carboplatin (AUC 2) and nab-paclitaxel 100 mg/m2 repeated as 28 day cycles x 3 (arm B). Pts with HER2 + BC received NCT similar to arm B, but with the addition of 12 weekly doses of trastuzumab given together with carboplatin and nab-paclitaxel (arm C). Core biopsies were performed prior to NCT and were preserved fresh frozen. 70-gene (MammaPrint™) profiling and 80-gene profiling (van de Vijver et al. NEJM 347:1999-2009, 2002) to categorize all tumors for basal-, HER2-, and luminal subtypes were carried out. We set out to assess the predictive value of Mammaprint scores (poor vs. good), as well as basal, vs. luminal, vs. HER2 molecular subtype profiling, for response to treatment on arms A vs. B vs. C. Responses were dichotomized as complete or near complete response (Symmans RCB scores of 0-1) vs. suboptimal response (RCB score > 1). Results: Sufficient amount of BC tissue and good quality RNA for gene array assessment were procured in 64% of the first 90 patients who have undergone pre-treatment core biopsies, and then proceeded to NCT, followed by definitive surgery. Here we report on the first 50 pts with complete set of data analyzed. The median age was 50 years (range:31-69). Pts were treated for stage II (49%) and III locally advanced (41%), and inflammatory BC (10%). By gene profiling, 28% of the tumors were HER2-type (vs. 38% by IHC 3+, or FISH, representing all pts treated on arm C), 26% basal-type, 42% luminal-type, and 4% borderline luminal-type. Poor-prognosis signature by the 70-gene (MammaPrint) assay was observed in 74% of pts: 92% of HER2-type, 100% of basal-type, and 52% of luminal-type tumors were characterized as poor-risk by the 70-gene assay. Following NCT, Symmans RCB scores of 0-1 were observed in 71% of pts with HER2-type, in 38% with basal-type, and 28% of pts with luminal-type molecular subtype characteristics. Conclusion: BC with HER2- and basal-molecular subtypes are more likely to respond to NCT and is frequently associated with poor-risk characteristics as determined by the 70-gene assay. The complete analysis of correlations among response to specific sets of NCT, molecular subtype, and 70-gene assay results in the entire pt population will be presented.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2026.