Citations

9082 Background: Human tumors, including melanoma, are complex mixtures of individual, molecularly distinct subpopulations, or clones of cancer cells. Effective cancer therapy will likely require targeting of all tumor subsets within a given cancer. Understanding the tumor complexity and the ability to identify points of therapeutic vulnerability within the individual tumor subsets will be essential for development of effective personalized cancer therapies. Methods: We have developed an approach that combines identification of individual tumor subsets using a multiparameter nuclear flow cytometry coupled with a high-resolution genomic analysis using the array-based comparative genomic hybridization (aCGH). Melanoma nuclei were isolated from tumor tissues and subjected to flow cytomery using melanocyte-specific antibodies (to separate melanoma cells from stroma) and DNA content, to separate individual tumor subpopulations. DNA extracted from isolated nuclear subpopulations was extracted and analyzed by aCGH. This approach was adopted for both fresh-frozen and paraffin-embedded clinical specimens. Results: We initially demonstrate the feasibility of the outlined approach by successful separation of melanoma from stromal nuclei and separation of individual melanoma nuclear subpopulations by DNA content. aCGH analysis of the DNA derived from isolated tumor subpopulations allowed successful identification of potentially targetable molecular aberrations in individual subsets of tumor cells. Notably, such aberrations were often not detected in unsorted, bulk tumors analyzed by the same high-resolution aCGH approach. Conclusions: We demonstrate a feasible approach to in-depth molecular analysis of tumor subpopulations within a clinical cancer tissue. This approach allows identification of potentially targetable molecular aberrations within individual tumor subsets, thus opening a possibility for a broad tumor targeting through design of individually-tailored therapeutic approaches. No significant financial relationships to disclose.

623 Background: Neoadjuvant therapy plays an important role in breast cancer treatment. Unlike patients who undergo surgery followed by adjuvant therapy,there are no established guidelines for surgical management following neoadjuvant therapy. Methods: Surgical practice patterns from 50 patients in N0338 “Phase II trial of Docetaxel and Carboplatin administered every two weeks as induction therapy for Stage II and Stage III breast cancer” were reviewed. The protocol did not mandate surgical therapy leaving the decision to the treating surgeon and patient. Results: 66% of patients underwent mastectomy (M) and 33% underwent breast conservation therapy (BCT). Three (9%) had immediate reconstruction. Eight (24%) underwent contralateral prophylactic M. Residual tumor size did not always impact primary surgical therapy. In the M group 4 (12%) had no residual disease, 15 (45%) < 2cm and 14 (42%) > 2cm; whereas, in the BCT group 1 (6%) had no residual disease, 12 (70%) < 2cm and 4 (24%) > 2cm. Axillary lymph node (ALN) staging varied tremendously. Three (6%) patients presented with palpable lymphadenopathy and proceeded to complete axillary lymph node dissection (ALND) after chemotherapy (CT). Fine needle aspiration (8) or core needle biopsy (7) of the axilla was performed in 15 (30%) patients before CT; 1 was negative and went on to have sentinel lymph node biopsy (SLNB) after CT; 14 (94%) were positive with 13 (86%) going on to ALND and 1 SLNB after CT. Five (10%) underwent SLNB prior to CT. One (20%) was positive and went on to have ALND after CT; 4 (8%) were negative and had no further ALN staging. A total of 19 (39%) had SLNB after neoadjuvant therapy; 13 (68%) were positive and underwent ALND; 1 SLNB failed; 2 of 5 that were negative underwent ALND with 1 having a positive lymph node. Ten (20%) underwent ALND with no pre-operative staging with 8 being positive for ALN metastases. Conclusions: Review of study data from multiple institutions revealed no consistent criteria in selection of surgical intervention for the breast tumor or ALN staging. There remains a need for further research in this area to establish standard practice guidelines. Support from NIH, sanofi-aventis, Amgen, Breast Cancer Research Foundation. No significant financial relationships to disclose.

AbstractBackgroundBenign capsular nevi (BCN) are not infrequent in sentinel lymph nodes (SLN) of patients with melanoma. Their prognostic significance is unknown and the literature is limited. This study evaluated the clinical significance of incidentally found BCN in these patients.MethodsA multi‐institutional retrospective review of patients undergoing SLN biopsy for cutaneous melanoma between 2000 and 2016. Patients were divided into the following groups: (a) negative SLN and no BCN, (b) negative SLN and presence of BCN, (c) positive SLN seen only on immunohistochemistry (IHC), and (d) positive SLN via hematoxylin and eosin (H&E). Outcomes measured were overall survival and any recurrence.ResultsA total of 1253 patients were identified (group 1 = 978, group 2 = 56, group 3 = 32, and group 4 = 187). Fifty‐seven percent were male and the mean age was 59.3 years. BCN was identified in 77 patients (6.2%), of which the majority was in the node‐negative group (72%). Multivariable analysis showed that BCN was associated with lower recurrence rates, though not statistically significant (hazard ratio [HR] = 0.5; P = .06). IHC‐ and H&E‐positive SLNs were associated with a higher risk of recurrence (HR = 2.4; P = .02 and 2.0, P < .0001, respectively).ConclusionPatients with BCN and negative SLN had lower recurrence rates than patients with negative SLN and no BCN. Our data suggest a possible protective effect against recurrence.

Linitis plastica (LP), a subset of gastric adenocarcinoma (GA), has been considered as a fatal disease with few management options. Little evidence has been reported regarding the role for surgical therapy in treating LP. A retrospective review of GA patients with LP from the surveillance, epidemiology, and end results database (2004–2009) was performed. 29,440 patients with GA were identified, of whom 948 (3.2%) had LP. After matching for American Joint Commission on Cancer (AJCC) stage, LP patients had significantly worse 5-year disease specific survival (DSS) compared with GA (6 vs 34%, P < 0.001). For potentially resectable LP patients (i.e., stage I–III), 5-year DSS was 0 per cent for no treatment and for radiation therapy alone, 18 per cent for both and surgery and radiation, and 20 per cent for surgery alone(P < 0.001). LP is a marker of poor survival in patients with GA. However, surgical resection provides the best oncologic outcomes in these patients with a 20 per cent 5-year DSS in patients with loco-regional disease.

Excisional biopsy has been recommended for papillary lesions diagnosed on core needle biopsy (CNB) because a significant proportion of cases are upstaged to in situ/invasive cancer after surgical excision. The study goals were to identify patients at lowest risk of upstaging in whom excisional biopsy may potentially be avoided. We retrospectively evaluated 46 patients with a papillary lesion on CNB. Six patients were upstaged overall (13%), to intraductal papillary carcinoma (7%), invasive papillary carcinoma (4%), and mixed invasive ductal/lobular carcinoma (2%). The upstaging rate for patients with atypia on CNB was higher than for patients without atypia (33 vs 3%, P = 0.011). No patient younger than 65 years was upstaged to in situ or invasive carcinoma, and the mean lesion size was also higher among patients who were upstaged ( P > 0.05). Patients younger than 65 years with small papillary lesions lacking atypia on CNB may therefore represent a low-risk group that may be offered close clinical and radiologic follow-up.

Abstract Background: Accurate circulating biomarkers for detecting residual disease can help guide therapy decisions, particularly in early-stage cancer patients. However, currently available methods lack the sensitivity required to confidently assess the presence of residual disease in patients with low tumor burden. To address this need, we have developed TARDIS (Targeted Digital Sequencing), a personalized, multiplexed amplicon sequencing method capable of tracking as many as 100 or more mutations simultaneously. Methods: We obtained tumor biopsies and longitudinal plasma samples from patients with early-stage breast cancer, glioblastoma, and pancreatic cancer. Each tumor biopsy was analyzed whole-exome sequencing. Founder mutations were selected, accounting for copy number alterations (analyzed using sequenza) and a consensus allele fraction approach that combined pyclone and custom in-house methods. Patient-specific TARDIS primers were designed to detect these mutations in plasma cfDNA. Error suppression in TARDIS was achieved using a combination of unique molecular identifiers and fragment sizes to group sequencing reads into read families. Results: In 33 patients with early-stage breast cancer treated with neoadjuvant therapy, we targeted between 3 and 116 (mean 30) mutations per patient and analyzed between 1 and 4 longitudinal plasma samples using TARDIS. Prior to treatment, we detected ctDNA in 100% patients with Stage I-III breast cancer (n=32, 95% CI= 89%-100%). We detected tumor-specific mutations in 100% of baseline breast cancer plasma samples. After completion of neoadjuvant therapy and before surgery, ctDNA levels were significantly lower in patients with pathologic complete response (pathCR, no evidence of disease at surgery) compared to patients with residual disease (median tumor fractions 0.003% and 0.017%, respectively, p=0.0058, AUC=0.83). Conclusions: TARDIS enables highly sensitive detection of ctDNA in patients with nonmetastatic cancers. Analysis of longitudinal plasma samples using TARDIS holds promise for personalizing the extent of treatment in patients with curable disease. Multiple clinical validation studies across cancer types are ongoing to define quantitative thresholds for changes in ctDNA levels that could improve clinical decision making. Citation Format: Bradon R. McDonald, Tania Contente-Cuomo, Stephen-John Sammut, Michelle D. Stephens, Ahuva Odenheimer-Bergman, Brenda Ernst, Nieves Perdigones, Suet-Feung Chin, Maria Farooq, Rosa Mejia, Patricia A. Cronin, Karen S. Anderson, Heidi E. Kosiorek, Donald W. Northfelt, Ann E. McCullough, Bhavika K. Patel, Jeffrey N. Weitzel, Thomas P. Slavin, Carlos Caldas, Barbara A. Pockaj, Muhammed Murtaza. Personalized monitoring of treatment response using Targeted Digital Sequencing of circulating tumor DNA [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A51.

AbstractBackground and ObjectivesNeoadjuvant endocrine therapy (NET) for ER+ breast cancer can downstage primary tumors. We evaluated NET efficacy in node‐positive patients.MethodsNode‐positive patients undergoing NET for ER+ breast cancer from 2012 to 2019 were reviewed. Primary endpoints included rates of axillary lymphadenectomy (ALND), pathologic complete response (pCR), and final nodal staging.ResultsThirty‐nine patients were included. Before NET, all were clinically node‐positive (cN1 = 36, 94%; cN2 = 2, 5%; cN3 = 1, 3%; Stage II = 23, 59%, Stage III = 16, 41%). After NET, nine (23%) had clinically persistent axillary disease necessitating ALND. The remaining 30 (77%) underwent sentinel lymph node biopsy (SLNB). Of these, 25 (83%) were SLNB+ on frozen section, undergoing immediate ALND. Five patients were negative on frozen section: one had a confirmed axillary pCR, and four had residual nodal disease on permanent pathology. One underwent delayed ALND, and for the remaining three patients, decision was made to forgo ALND. Final overall axillary staging was: N0 (pCR) = 1, 3%, pN1mic = 1, 3%, pN1 = 20, 51%, pN2 = 12, 30%, pN3 = 5, 13%; Stage II = 16, 41%, Stage III = 23, 59%.ConclusionsWhile NET is reported to downstage primary tumors, downstaging of the axilla was unsuccessful in the majority of patients.

LBA2 Background: About 6% of newly diagnosed breast cancer patients present with Stage IV disease and an intact primary tumor (IPT). Locoregional treatment (LRT) for the IPT is hypothesized to improve survival based on retrospective analyses, but randomized trials have provided conflicting data. We now report the results of E2108, a Phase 3 trial that examined the worth of LRT for the IPT following initial systemic therapy. Methods: Stage IV patients with IPT were registered, treated with optimal systemic therapy (OST) based on patient and tumor characteristics; those who did not progress during 4-8 months of OST were randomized to LRT for the IPT, or no LRT. The primary endpoint was overall survival (OS), with locoregional disease control as a secondary endpoint. Stratified log rank test and Cox proportional hazard model were used to compare OS between treatment groups. Cumulative incidence of locoregional recurrence/progression was estimated and Gray test was used for treatment group comparisons. The trial was designed to detect an improvement in 3 year OS rate from 30% with OST alone to 49.3% for OST+LRT (power 95%, 1-sided alpha 0.05) with full information expected after 152 deaths; the data monitoring committee recommended data release after 80% of full information. Results: 390 patients were enrolled between 2/8/11 and 7/23/15, and received OST. Of these, 256 eligible patients were randomized to either continued OST alone (N = 131) or OST+LRT (N = 125).There were 121 deaths and 43 locoregional progression events after a median follow up 59 months (range: 0-91). There was no significant difference in OS (3-year OS rate 68.4% in OST+LRT vs. 67.9% OST alone arm, stratified log-rank p = 0.63, HR = 1.09, 90% CI: 0.80, 1.49) or in progression-free survival (p = 0.40). The locoregional recurrence/progression was significantly higher in the OST alone arm (3-year rate 25.6% vs 10.2%, Gray test p = 0.003). Health-related quality of life (HRQOL) measured by FACT-B Trial Outcome Index was significantly worse in the OST+LRT arm than OST alone arm at 18 months post randomization (60% completion, Wilcoxon rank sum test p = 0.01), but no difference was observed at time points 6 months (74% completion) or 30 months (56% completion). Conclusions: Early local therapy does not improve survival in patients with de novo metastatic breast cancer and an IPT. Although there was a 2.5-fold higher risk of local disease progression without LRT, LRT of the IPT did not lead to improved HRQOL. Clinical trial information: NCT01242800 .

Worldwide, millions of women live with breast implants. Therefore, it is important that physicians be aware of an uncommon but possibly serious complication arising from breast implants: breast implant–associated anaplastic large cell lymphoma (BIA-ALCL). Breast implant–associated anaplastic large-cell lymphoma most commonly presents as a delayed fluid collection around a textured breast implant or as a mass in the capsule surrounding the implant. The exact pathogenesis of the disease remains unclear. The neoplastic cells of BIA-ALCL show strong uniform staining for CD30 and are consistently negative for activin receptor-like kinase 1. Patients with confirmed cases should be referred to a lymphoma specialist or breast medical oncologist for a complete oncologic evaluation before any surgical intervention. For disease confined to the fluid accumulation or capsule, or both, surgical removal of the implant and complete capsulectomy is the preferred treatment. Postoperative chemotherapy or radiation, or both, are not considered necessary for patients with limited-stage disease and are reserved for advanced disease stages. Generally, BIA-ALCL is a local disease that follows an indolent course and has an excellent prognosis. Although complete remission of disease has occurred in patients with BIA-ALCL, median overall survival is reduced. As of March 2018, approximately 529 unique, confirmed BIA-ALCL cases had been reported in 23 countries. To date, 16 patients have died from BIA-ALCL, and all had extracapsular involvement. The aim of this article is to summarize the diagnosis, evaluation, and management of BIA-ALCL, based on established guidelines, for all practitioners who may care for patients with breast implants.