Citations

PURPOSEMore than 80% of patients who undergo sentinel lymph node (SLN) biopsy have no nodal metastasis. Here, we describe a model that combines clinicopathologic and molecular variables to identify patients with thin- and intermediate-thickness melanomas who may forgo the SLN biopsy procedure because of their low risk of nodal metastasis.PATIENTS AND METHODSGenes with functional roles in melanoma metastasis were discovered by analysis of next-generation sequencing data and case-control studies. We then used polymerase chain reaction to quantify gene expression in diagnostic biopsy tissue across a prospectively designed archival cohort of 754 consecutive thin- and intermediate-thickness primary cutaneous melanomas. Outcome of interest was SLN biopsy metastasis within 90 days of melanoma diagnosis. A penalized maximum likelihood estimation algorithm was used to train logistic regression models in a repeated cross-validation scheme to predict the presence of SLN metastasis from molecular, clinical, and histologic variables.RESULTSExpression of genes with roles in epithelial-to-mesenchymal transition (glia-derived nexin, growth differentiation factor 15, integrin-β3, interleukin 8, lysyl oxidase homolog 4, transforming growth factor-β receptor type 1, and tissue-type plasminogen activator) and melanosome function (melanoma antigen recognized by T cells 1) were associated with SLN metastasis. The predictive ability of a model that only considered clinicopathologic or gene expression variables was outperformed by a model that included molecular variables in combination with the clinicopathologic predictors Breslow thickness and patient age (area under the receiver operating characteristic curve, 0.82; 95% CI, 0.78 to 0.86; SLN biopsy reduction rate, 42%; negative predictive value, 96%).CONCLUSIONA combined model that included clinicopathologic and gene expression variables improved the identification of patients with melanoma who may forgo the SLN biopsy procedure because of their low risk of nodal metastasis.

Objectives We compared risk-adjusted short- and long-term outcomes between standard pancreaticoduodenectomy (SPD) and a pylorus-preserving pancreaticoduodenectomy (PPPD). Methods The National Cancer Database was queried for the years 2004 to 2014 to identify patients with adenocarcinoma of the pancreatic head undergoing SPD and PPD. Margin status, lymph node yield, length of stay (LOS), 30- and 90-day mortality, and overall survival were compared. Results A total of 11,172 patients were identified, of whom 9332 (83.5%) underwent SPD and 1840 (16.5%) PPPD. There was no difference in patient age, sex, stage, tumor grade, radiation treatment, and chemotherapy treatment between the 2 groups. Total number of regional lymph nodes was examined, and surgical margin status and overall survival were also comparable. However, patients undergoing PPPD had a shorter LOS (11.3 vs 12.3 days, P < 0.001), lower 30-day mortality (2.5% vs 3.7%, P = 0.02), and 90-day mortality (5.5% vs 6.9%, P = 0.03). On multivariate analyses, patients undergoing SPD were at higher risk for 30-day mortality compared with PPPD (odds ratio, 1.51; 95% confidence interval, 1.07–2.13). Conclusions Standard pancreaticoduodenectomy and PPPD are oncologically equivalent, yet PPPD is associated with a reduction in postoperative mortality and shorter LOS.

Abstract Introduction: Amplification of chromosome 9p24.1 encoding PDL1, PDL2, and JAK2 (the PDJ amplicon) has been detected in 5-25% of triplenegative breast cancers (TNBC), and is associated with poor outcome and activation of the JAK/STAT pathway. Here, we have developed a robust multiplexed fluorescence in situ hybridization (FISH) assay for detection of 9p24.1 amplification, and assessed the frequency and cellular distribution of the PDJ amplicon in a cohort of African American (AA) women with TNBC. Methods: The FISH assay combines three chromosome 9 probes to simultaneously target JAK2 and PD-L1 (9p24.1, PDJ), chromosome 9q22, and the 9q34.1 regions. This enables discrimination of PDJ amplicons from whole chromosome 9p arm gains and from chromosome 9 ploidies that occur in the background of genomic instability in aneuploid cancer genomes. Fifty cells were scored for each probe and the average copy number was obtained. We defined PDJ amplification as PDJ&gt;4, PDJ/9q22 ratio≥2, and/or PDJ/9q34.1 ratio≥2. The assay was benchmarked to array CGH of flow sorted TNBC tissue from Mayo Clinic Arizona (n=14). Tissue microarrays from TNBC PDX tumors (n=20) and from African American women with TNBC (n=87) were assessed. Results: Using selected TNBC tissue with known CGH data, the FISH assay tightly correlated with PDJ copy number in 13/14 cases. The discordant case was negative by CGH on a biopsy with low tumor content, but FISH positive on tissue section (PDJ &gt;7.5 and a PDJ/9q22 ratio=4). Of 20 TNBC PDX tumors, 5 were amplified by FISH. Twelve of 87 (14%) of tumors had PDJ amplification by FISH, of which ten were from breast tissue and two were from lymph node. Of these 12, PDJ&gt;4 (n=0), PDJ/9q22 ratio≥2 (n=6), and PDJ/9q34.1 ratio≥2 (n=10). Significant intratumoral variation was observed with the presence of single cells with &gt;10 PDJ copies in 8/17 (47%) amplified and 0/90 non-amplified total cases. Conclusion: 9p24.1 (PDJ) amplification encoding JAK2, PD-L1, and PD-L2 is detected by three-color FISH in 14% of TNBC from African American women. Individual cells with ≥10 copies of PDJ was seen exclusively in 8/17 amplified cases. We identified 5 PDX tumors which may provide valuable preclinical models for the amplicon. The association of this biomarker with clinical outcome will be presented. Citation Format: Karen S. Anderson, Tammey Naab, Lori K Koslosky, Megan Anderson, Michael Lewis, Yasmine Kanaan, Ali Afsari, Luisel Ricks-Santi, Barbara A. Pockaj, Michael T Barrett. Tissue prevalence and cellular heterogeneity of 9p24.1 amplification in TNBC in African American women [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-10-17.

9034 Background: Routine imaging for staging of early stage cutaneous melanoma is not recommended by National Comprehensive Cancer Network (NCCN) guidelines. Besides the low probability of finding metastatic disease, detrimental aspects include false-positives and additive cost. We sought to investigate the use of imaging for staging of cutaneous melanoma in the United States. Methods: Patients with newly diagnosed clinically node negative cutaneous melanoma between 2000-2007 were identified from the Surveillance Epidemiology End Results-Medicare registry. Any imaging performed within 90 days following diagnosis was considered a staging study. Patients with metastatic disease were excluded. Results: A total of 25,643 patients were identified, of whom 10,775 (42%) underwent imaging. The mean age was 76.1 years, with the majority being male (61.8%) and Caucasian (98.4%). Breakdown by T classification of the primary was as follows: T1 (63%), T2 (17%), T3 (12%), and T4 (8%). A chest Xray was performed for 9,737 (38.0%), while 3,176 (12.4%) underwent advanced staging imaging studies; PET (7.2%), CT (5.9%), MRI (0.6%), and Ultrasound (0.4%). The use of advanced imaging steadily increased over the period of our study from 9.0% in 2000 to 16.3% in 2007 (p<0.001). When stratified by T classification, advanced imaging was used for 8.9% of T1, 14.5% of T2, 18.8% of T3 and 27.0% of T4 tumors (p<0.001). Similarly, node positive patients (4.7%) underwent advanced imaging 33.4% of the time compared to 11.3% for node negative patients (p<0.001). On multivariate analysis, factors predictive of advanced imaging include higher T classification (OR 3.12 T4 vs. T1, CI 2.77-3.52, p<0.001), node positivity (OR 2.70, CI 2.36-3.09, p<0.001), more recent year of diagnosis (OR 2.01 2007 vs. 2000, CI 1.71-2.37, p=0.006), high school education (OR 1.62, CI 1.43-1.83, p<0.001), non-Caucasian race (OR 1.37, CI 1.05-1.77, p=0.018), and male gender (OR 1.12, CI 1.03-1.21, p=0.006). Conclusions: Contrary to current recommendations, performance of advanced imaging for staging of early stage cutaneous melanoma is increasing in the Medicare population. Further research is needed to identify factors driving this increase.

1037 Background: Folate receptor alpha (FRA the product of the FOLR1 gene) has been identified as a potential prognostic and therapeutic target in a number of cancers. A correlation has been shown between intense expression of FRA in breast tumors and poor prognosis, yet little is known about FOLR1/FRA expression across clinically relevant breast cancer subtypes. Methods: 131 breast cancer tumors including 4 benign, 33 ER+, 26 HER2+, and 68 triple negative (TN) were constructed into tissue microarrays (TMAs). FRA expression was analyzed by immunohistochemistry (IHC) using a high affinity FRA antibody. Tumor membrane staining intensity was scored by a pathologist as negative (0), weak (1+), moderate (2+) and strong (3+). The percent of cells within each tissue core stained at each intensity was recorded to calculate an H-score. The H-score is a weighted score that captured both the proportion of positive staining and intensity for each tumor. H-score values can range from zero (no membrane staining) to a maximum of 300 (100% membrane staining at 3+). H-scores for each patient sample were averaged over 3 TMA cores. The mean H-scores for each tumor subtype and the percentage of 3+ staining in >30% of tumor cells were compared by a Mann-Whitney test. The distribution of FOLR1 mRNA was completed using a TCGA RNA-seq dataset from 691 breast tumors classified as ER+, HER2+ and TN. FOLR1 levels of TN versus ER+ and HER2+ were compared by a Mann-Whitney test. Results: The mean H-score for the benign tumors was 0, ER+ (13.31), HER2+ (39.36), TN (119.02). The median H-score for the benign tumors was 0, ER+ (0), HER2+ (7.5), TN (127.5). The TN tumors mean and median H scores were significantly higher than benign, ER+ or HER2+ (p<0.001). The largest percentage of 3+ staining in >30% of tumor cells was observed in TN tumors (36.7%) and lowest in ER+ tumors (0%) (p<0.001). TN tumors had significantly higher levels of FOLR1 mRNA compared to ER+ and HER2+ subtypes (p<0.0001). Conclusions: Our data indicate that expression of FRA is highly prevalent in TN tumors and is supported by FOLR1 mRNA levels. Anti-FRA therapy may represent an important therapeutic intervention in TNBC who to this point have no active targeted treatment options.

8530 Background: RAD-001 (Everolimus) is an oral inhibitor of mammalian target of rapamycin (mTOR). Interim analysis results from a phase II study of RAD-001 in patients with metastatic melanoma (MM) were presented at ASCO 2005. This study was re-opened using a higher dose based on an improvement in the 16 week progression free survival (PFS) rate and good tolerability. Methods: A two- stage, phase II multi-institutional trial was conducted in patients with MM to assess that 16 weeks PFS rate was at least 50%. Inclusion criteria: measurable disease, ECOG performance score of 0–2. Exclusion criteria: presence of intracranial metastases, concurrent use of inducers of cytochrome 3A4 and abnormal organ function. The dose of RAD-001 in the second cohort was increased to 10 mg daily (increased from 30 mg weekly) based on evidence of safety of the higher dose. Results: Twenty-nine patients were enrolled; baseline information is available on 27. Median age was 63 yrs; 15 (56%) had >2 sites of metastatic disease. Most (48%) had stage M1c disease. PS was 0, 1 and 2 in 58%, 38% and 4%. All but 4 (15%) had received prior therapy. Grade 3 adverse events included stomatitis and fatigue (2 each), leukopenia, neutropenia, diarrhea, anorexia, dehydration, dyspnea, hyperglycemia, and hypersensitivity (1 each). Planned interim analysis was done after 20 patients were enrolled. 14 (70%) had progressed 16 weeks, failing to meet the decision rule needed (PFS >30%) to restart accrual. The median PFS for all 29 patients was 56 days. The median overall survival (OS) has not been reached. For the entire cohort of 53 pts treated on this study (at both dose levels), the median PFS, median OS were 59 and 286 days respectively. Conclusion: Interim analysis after enrollment of 20 patients at a higher dose of RAD-001 demonstrated significantly more toxicity and no added clinical efficacy. The 16 week PFS rate target was not reached, and accrual was suspended. No significant financial relationships to disclose.

612 Background: The adoption of new breast surgical techniques has been rapid for early stage breast cancer. The utilization of these techniques in patients with high risk operable breast cancer has not been thoroughly investigated. Methods: Retrospective surgical data was summarized for patients entered into N9831 “Phase III Trial of Doxorubicin and Cyclophosphamide Followed by Weekly Paclitaxel With or Without Trastuzumab as Adjuvant Treatment for Women With HER-2 Over-expressing or Amplified Node Positive or High-Risk Node Negative Breast Cancer.” Results: 3,505 patients were entered into N9831 from 2000–2005 following primary surgery for breast cancer. The median age was 50 and 43% were premenopausal. 93% of patients underwent a diagnostic biopsy prior to their definitive surgical procedure. Whether HER2-neu status was available at time of definitive surgery is unknown. 61% underwent a mastectomy whereas 39% underwent breast conserving surgery (BCS). The rate of BCS was relative stable over the course of the trial. Patients with T1 tumors had a higher rate of BCS (49%) compared to T2 tumors (37%) and T3 tumors (6%). Sentinel lymph node (SLN) biopsy was performed in 54% of the cases. The rate of SLN biopsy increased from 40% in 2000 to 66% in 2005. Patients who underwent mastectomy had a lower rate of SLN biopsy than patients who underwent BCS (44% versus 71%, respectively). Tumor size was also associated with the rate of SLN biopsy: T1 (60%), T2 (53%), and T3 (36%). Data on local and regional recurrences are still maturing. Conclusions: Surprisingly, low numbers of patients on this trial underwent BCS whereas the adoption of the SLN biopsy procedure among the same group of surgeons was relatively high. The relatively low rate of BCS in this study population needs further investigation to determine what surgeon and patient factors impacted the surgical decision. No significant financial relationships to disclose.

The breast is a rare site for metastases, and their molecular characteristics have not been studied yet. Intrinsic molecular genetics, cancer characteristics, and breast tissue immune responses in diverse metastases to the breast have not been previously studied. We identified 64 patients with cancers metastatic to the breast: 51 carcinomas and 13 melanomas. Programmed death ligand 1 (PD-L1), steroid receptors, and HER2/neu expressions were evaluated using immunohistochemistry. Gene sequencing, copy number alterations, microsatellite instability, and tumor mutational burden were performed using next-generation sequencing platforms. The 3 most common primary sites for metastatic carcinomas were lung (37%), ovary (29%), and fallopian tubes/peritoneum (14%). TP53 mutations were commonly (50%) observed among the carcinoma cases, while other mutations were characteristic for the primary cancers (VHL in renal, BRCA1 in the fallopian tube, and BRAF in melanomas). High tumor mutational burden was detected in 5/14 carcinomas and 3/7 melanomas. Tumor cell PD-L1 expression was detected in 6 carcinomas, but not in any of the melanomas, whereas immune cells’ expression of PD-L1 was seen in 17 carcinomas and 6 melanomas. Estrogen receptor status was positive in 13/49 carcinomas including 12 adenocarcinomas originating from the ovary and fallopian tube or peritoneum and 1 duodenal neuroendocrine carcinoma. No carcinoma was HER2/neu positive. Intrinsic genetic characteristics of the metastases to the breast followed the pattern commonly seen in primary tumors. Biomarkers of potential benefit to immune checkpoint inhibition therapy were limited to PD-L1-positive non–small cell lung cancer. No common characteristics of the heterogeneous group of tumor metastases to this organ were identified.

A robust personalized ctDNA test, TARDIS, achieves high accuracy for residual disease after completion of neoadjuvant therapy.