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 P1-10-20: A multi-center trial of intra-operative electronic brachytherapy during breast conservation surgery for early stage breast cancer: Early results of unplanned boost participants

Objective

To assess the safety and efficacy of single-fraction, intra-operative radiation therapy (IORT) delivered as a boost using the Xoft® Axxent® Electronic Brachytherapy System® (eBx®) immediately following surgical resection for treatment of early stage breast cancer.

Methods

This phase 4, open-label, single-arm, prospective, non-randomized trial is still enrolling participants and is currently being conducted at 26 hospitals in the USA (25) and Portugal (1). 878 participants with biopsy-proven ductal carcinoma in situ (DCIS) or invasive ductal carcinoma who met the inclusion criteria underwent lumpectomy followed by single-fraction IORT to the lumpectomy cavity. Briefly, a small, presterilized lead shield piece was placed on the chest wall to reduce the dose to the ribs, and then a balloon applicator, suitable to the surgical bed, was placed in the lumpectomy cavity and inflated with saline (30-75 cc); skin was temporarily closed over the balloon and ultrasound was used to confirm a balloon surface-to-skin distance ≥ 1.0 cm. The Xoft System was used to deliver the 20 Gy dose at the balloon applicator surface. The balloon was deflated, lead shield and balloon removed and the surgical site sutured. Upon the presence of additional risk factors, 37 participants subsequently received whole breast radiation therapy (WBRT); thus, these participants received an unplanned IORT boost and were removed from the primary analysis but will continue to be followed for the duration of the 10-year study. Cosmesis (Harvard Scale) was assessed in this subset of participants. The primary outcome for the main trial is recurrence of ipsilateral breast tumor at 5 years. Trial Registry: ClinicalTrials.gov; Identifier: NCT01644669.

Early Findings

37 boost participants received WBRT (up to 50 Gy) after IORT (36 received the prescribed 20 Gy dose; one received 14 Gy). Mean follow-up time was 430 days (range 13-1119). Mean age at IORT was 62 years (range 45-78). Boost participants had either DCIS (N=5) or invasive ductal carcinoma (N=32). The DCIS nuclear grade was high (N=3), intermediate (N=1), or low (N=1). Invasive cancers were Grade 1 (N=15), 2 (N=10), 3 (N=6), or unknown (N=1). 29 participants had T1, 3 had T2, and 5 had Tis lesions. Mean tumor size was 13.04 ± 10.26 mm. For the two participants who have reached 3-year follow-up, cosmesis was excellent (N=1) and fair (N=1). For the six participants who have reached 2-year follow-up, cosmesis was excellent (N=4), good (N=1), and fair (N=1). There was one serious adverse event with a Grade 3 for skin necrosis. The most frequent side effects were seroma (10%), edema (9%), pain (9%), erythema (6%), and induration (5%). There have been no deaths, recurrences, or new primary tumors among the boost participants to date.

Conclusions

Early results from this multi-center trial suggest that IORT as a tumor-bed boost using the Xoft Axxent eBx System at the time of breast conservation surgery is safe and has low morbidity. To date, the majority of participants receiving an unplanned IORT boost have had excellent to good cosmetic results and the majority of adverse events have been low-grade.

Funding

Funded by Xoft, Inc., a subsidiary of iCAD, Inc.

Citation Format: Syed AMN, Chang H, Schwartzberg B, Bremner A, Boylan S, Lopez-Penalver C, Vito C, Davis M, Dooley W, Chakravarthy AB, Coomer C, Proulx G, Golder S, Ivanov O, Fernandez K, Farha MJ, Gonzalez V, Wengler C, Bhatnagar A, Neuner GA, Kopkash K, Rahman S, Costa P. A multi-center trial of intra-operative electronic brachytherapy during breast conservation surgery for early stage breast cancer: Early results of unplanned boost participants [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 P1-10-20.

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 P1-14-10: 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 P3-12-11: One-year follow-up results of a multi-center trial of intra-operative radiation therapy using electronic brachytherapy at the time of breast conservation surgery for early stage breast cancer

Objectives: To describe observations of one-year follow-up of subjects treated on a multi-center, non-randomized study with a single fraction of intra-operative radiation therapy (IORT) using the Xoft® Axxent® Electronic Brachytherapy System® (eBx®) immediately following surgical resection of early stage breast cancer.

Methods: Two-hundred forty three (243) subjects were treated at seventeen (17) US hospitals. Upon meeting the inclusion/exclusion criteria, patients underwent partial mastectomy, placement of a balloon applicator suitable to the surgical bed in the lumpectomy cavity and inflated with saline (30 – 75 cc). The skin was temporarily closed over the balloon and ultrasound examination performed to confirm that the balloon surface-to-skin distance was > 1.0 cm. A single fraction of intra-operative radiation therapy was delivered to the lumpectomy cavity using the Xoft System. The prescribed dose was 20 Gy at the balloon applicator surface, and the mean treatment time was 10.2 minutes. After treatment, the balloon was deflated and removed, and skin sutured.

Results: Two-hundred forty two (242) subjects received the prescribed dose of 20 Gy; one subject received 21 Gy. Eighteen (18) subjects were removed from the primary analysis post-IORT due to positive surgical margins (N=2), positive sentinel lymph nodes (N=13), or balloon surface-to-skin distance < 1 cm (N=3). However, these eighteen subjects will continue to be followed for the duration of this 10-year study. The mean follow-up for the two-hundred twenty five evaluable subjects is 494 days (range 300-465 days). The mean patient age was 65 years (41-89). Forty-nine subjects (21.8%) had ductal carcinoma in situ, one-hundred seventy one (76%) had invasive ductal carcinoma, and five (2.2%) had unknown histology. The DCIS nuclear grade was evenly distributed between high (N=18) and low/intermediate (N=23); 5 were unknown. Invasive cancer was Grade 1-2 in 142/171 cases. Two-hundred twelve subjects (94.2%) had T1 lesions, eight (3.6%) had T2 lesions, and five (2.2%) were unknown. The mean tumor size was 10.6 mm ± 6.4 mm. At the time of the last subject visit, 49/318 reported adverse events were Grade 2 or higher, and only 1/100 had serious side effects, i.e. infection. One patient died of aortic aneurism and two developed secondary malignancies, i.e. ovarian cancer and chronic lymphocytic leukemia. The most frequent side effects were seroma (12.5%), erythema (9.1%), and induration (7.5%). Cosmesis was excellent to good in 95% of cases.

Conclusions: IORT using the Xoft System as part of the conservative treatment of breast cancer is safe, with low morbidity. Early results from this multi-center trial demonstrate this short, convenient course of radiation therapy for select patients with early stage breast cancer has excellent-to-good cosmetic results and a low rate of low-grade adverse events.

Citation Format: Syed AMN, Chang H, Schwartzberg BS, Bremner AK, Lopez-Penalver C, Coomer C, Boylan S, Chakravarthy A, Vito CA, Bhatnagar A, Proulx GM, Dooley WC, Davis M, Golder SL, Ivanov O, Fernandez K, Rahman S. One-year follow-up results of a multi-center trial of intra-operative radiation therapy using electronic brachytherapy at the time of breast conservation surgery for early stage 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 P3-12-11.

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.