PAM50 Subtypes in Baseline and Residual Tumors Following Neoadjuvant Trastuzumab-Based Chemotherapy in HER2-Positive Breast Cancer: A Consecutive-Series From a Single Institution

Introduction: HER2-enriched subtype has been associated with higher response to neoadjuvant anti-HER2-based therapy across various clinical trials. However, limited data exist in real-world practice and regarding residual disease. Here, we evaluate the association of HER2-enriched with pathological response (pCR) and gene expression changes in pre- and post-treatment paired samples in HER2-positive breast cancer patients treated outside of a clinical trial.

Methods: We evaluated clinical-pathological data from a consecutive series of 150 patients with stage II-IIIC HER2-positive breast cancer treated from August 2004 to December 2012 with trastuzumab-based neoadjuvant chemotherapy. Expression of 105 breast cancer-related genes, including the PAM50 genes, was determined in available pre-and post-treatment formalin-fixed paraffin-embedded tumor samples using the nCounter platform. Intrinsic molecular subtypes were determined using the research-based PAM50 predictor. Association of genomic variables with total pCR was performed.

Results: The pCR rate was 53.3%, with higher pCR among hormonal receptor (HR)-negative tumors (70 vs. 39%; P < 0.001). A total of 89 baseline and 28 residual tumors were profiled, including pre- and post-treatment paired samples from 26 patients not achieving a pCR. HER2-enriched was the predominant baseline subtype not only in the overall and HR-negative cohorts (64 and 75%, respectively), but also in the HR-positive cohort (55%). HER2-enriched was associated with higher pCR rates compared to non-HER2-enriched subtypes (65 vs. 31%; OR = 4.07, 95% CI 1.65–10.61, P < 0.002) and this association was independent of HR status. In pre- and post-treatment paired samples from patients not achieving a pCR, a lower proportion of HER2-enriched and twice the number of luminal tumors were observed at baseline, and luminal A was the most frequent subtype in residual tumors. Interestingly, most (81.8%) HER2-enriched tumors changed to non-HER2-enriched, whereas most luminal A samples maintained the same subtype in residual tumors.

Conclusions: Outside of a clinical trial, PAM50 HER2-enriched subtype predicts pCR beyond HR status following trastuzumab-based chemotherapy in HER2-positive disease. The clinical value of intrinsic molecular subtype in residual disease warrants further investigation.

Prognostic value of PAM50 in residual breast cancer following neoadjuvant endocrine therapy (NET): A retrospective analysis with long follow-up

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Background: NET is gaining more acceptances for the management of hormonal receptors (HR)-positive breast cancer (BC). To date, the decrease of Ki-67 and PEPI score are the only prognostic factors associated with relapse-free survival after NET. PAM50 is a validated prognostic test in newly diagnosed BC; however, its value in residual tumors after NET is currently unknown. Methods: We took tumor tissues from patients of a retrospective study of 119 postmenopausal women with HR-positive stage II-III BC. Patients were diagnosed from 1997 to 2009 and were treated with NET for a median duration of 8.5 months . Median age was 74 (63-88). After NET all patients underwent surgery (73% conservative). Adjuvant treatment were endocrine therapy in 100%, radiotherapy in 76.5% and chemotherapy 7%. Median follow-up from surgery was 112 months. Median follow-up from surgery was 112 months. We observed 26 (24%) of distant relapses and 75 deaths (44 without cancer). Median overall survival was 134.8 months. RNA was extracted from FFPE tumor tissues of surgical specimens. A panel of 55 BC-related genes, including the research-based PAM50 assay (subtypes, ROR-S and ROR-P pre-defined cutpoints), androgen receptor (AR), immune genes (CD8A, CD4, PDL1 and PD1). Uni- and multi-variable Cox models were used to evaluate the association of each variable with distance recurrence free interval (DRFI). Results: PAM50 subtype distribution: Luminal A 54.3%, Normal-like 24.3%; HER2-enriched 16,5%, Luminal B 1% and basal 1%. Distribution of ROR-S groups was Low 64%, medium 30%and high 6%. Distribution of PEPI score was: 0 in 43%, 3 in 37% and 6 in 20%. Among the different variables explored, PEPI score 0 (HR 0.27 [95%IC 0.09-0.79] p=0.001), low ROR-S (HR 0.39 [95%CI 0.17-0.91] p=0.001) and high AR expression (HR 0.71 [95CI 0.53-0.96] p=0.007) were significantly associated with lower DRFI in univariate analyses. After adjusting for PEPI (with or without Normal-like tumors), ROR-S and AR remained significantly associated with outcome. Conclusions: PAM50 ROR-S and AR expression in residual tumors after NET provide independent prognostic information beyond PEPI. With further validation, these biomarkers could help clinicians in the decision-making of adjuvant chemotherapy.

The C Allele of ATM rs11212617 Associates With Higher Pathological Complete Remission Rate in Breast Cancer Patients Treated With Neoadjuvant Metformin

Background: The minor allele (C) of the single-nucleotide polymorphism (SNP) rs11212617, located near the ataxia telangiectasia mutated (ATM) gene, has been associated with an increased likelihood of treatment success with metformin in type 2 diabetes. We herein investigated whether the same SNP would predict clinical response to neoadjuvant metformin in women with early breast cancer (BC). Methods: DNA was collected from 79 patients included in the intention-to-treat population of the METTEN study, a phase 2 clinical trial of HER2-positive BC patients randomized to receive either metformin combined with anthracycline/taxane-based chemotherapy and trastuzumab or equivalent regimen without metformin, before surgery. SNP rs11212617 genotyping was assessed using allelic discrimination by quantitative polymerase chain reaction. Results: Logistic regression analyses revealed a significant relationship between the rs11212617 genotype and the ability of treatment arms to achieve a pathological complete response (pCR) in patients (odds ratio [OR]_{genotype×arm} = 10.33, 95% confidence interval [CI]: 1.29-82.89, p = 0.028). In the metformin-containing arm, patients bearing the rs11212617 C allele had a significantly higher probability of pCR (OR _A/C,C/C = 7.94, 95%CI: 1.60-39.42, p = 0.011). Conversely, no association was found between rs11212617 and clinical response in the reference arm (OR _A/C,C/C = 0.77, 95%CI: 0.20-2.92, p = 0.700). After controlling for tumor size and hormone receptor status, the rs11212617 C allele remained a significant predictor of pCR solely in the metformin-containing arm. Conclusions: If reproducible, the rs11212617 C allele might warrant consideration as a predictive clinical biomarker to inform the personalized use of metformin in BC patients. Trial Registration: EU Clinical Trials Register, EudraCT number 2011-000490-30. Registered 28 February 2011, https://www.clinicaltrialsregister.eu/ctr-search/trial/2011-000490-30/ES.

Abstract P5-15-09: Impact of oncotype dx genetic signature used in early breast cancer. Clinical and economic analisys of a 110 patient cohort treated in the Catalan Oncologic Institute (ICO), Spain

Introduction

Benefit from adjuvant chemotherapy (CT) is doubtful in a high percentage of patients with early breast cancer. The 21-gene recurrence-score (RS) assay (Oncotype DX, Genomic Health) is one gene-expression assay that provide prognostic and predictive information in hormone-receptor (RH) positive breast cancer. The results of the TAILORx study have confirmed that the majority of patients with tumors RH + and HER2 negative can avoid CT without increasing their risk of relapse. From 2012 to 2015 we used Mammaprint (MMP), in our institution and 60% of cases could avoided CT (communicated in SABCS 2015). Since 2017 we use RS for this purpose.

Primary Objective

To analyze the impact of using RS to change the indication of adjuvant CT.

Secondary Objectives

To analyze the association between different clinical pathological factors and the RS value, and calculate the difference between the cost of all RS test and the cost in direct expense of the treatment with CT of all patients who could avoid it thanks to the RS

Material and methods

We analyzed all RS test performed in the three ICO centers during 2017. We sent 112 tumor samples; in 2 samples adequated RNA for RS was not obtained. We compared the adjuvant treatment initially planned according to institutional treatment protocol with the treatment given after RS. We compared the direct economic costs of CT with the costs of the diagnostic test, and performed a logistic regression analysis of some pathological factors and RS value.

Results

The RS could be determined in 110 of 112 cases, in which there was indication of adjuvant CT. Only 14 patients received CT (12,72%) with the RS value, so CT was avoided in 96 patients (87,28%).

The clinical-pathological characteristics of the series are summarized in the table 1. Of the risk factors analyzed, only grade 3 (p 0.001) and PR &lt;20% (p&lt;0.002) showed a statistically significant relationship with a higher probability of RS&gt; 25. No association was found between age, nodal status, tumor diameter, Ki67, Infiltrating Ductal Carcinoma vs neither Infiltrating Lobular Carcinoma nor Lympho-Vascular invasion.

The cost of the genetic studies was 180000€ (1636€ each). The cost of each CT schedule (EC x 4 followed by paclitaxel x 12) was 7214€ and the total cost of 96 cases 692590€. Direct costs savings estimated from the reduction in CT treatment were 512590€

Conclusion: Our series shows that RS avoided unnecessary CT in 87% of cases and was more cost-effective than a previous series with MMP. G3 and RP &lt;20 were the only pathological factors associated with an increased risk of RS&gt; 25.

Table 1.Patients characteristics and clinical-pathological details from the analyzed tumorsPatient characteristicsAge, mean (range)53,76 (19 – 75)≥50y72 (65.5%)&lt;50y38 (34.5%)HistologyInfiltrating ductal carcinoma88 (80%)Infiltrating lobular carcinoma20 (18,2%)Others2 (1,8%)TNMTumor diameter (mm), mean (range)19,25 (1 – 160)pN058 (52,7%)pN1mic21 (19%)pN131 (28,3%)Hormone receptorsRE 2-100%110 (100%)RP &lt;20%22 (20%)RP ≥20%88 (80%)Ki67 median, mean (range)20, 21 (2-75)Lymphovascular invasionyes9 (8%)no101 (92%)Adjuvant treatmentCT14 (12,72%)Hormonotherapy96 (87,28%)

Citation Format: Ferrer M, Dorcas J, Quiroga V, Margelí M, del Barco S, Stradella A, Petit A, Falo C, Viñas G, Romeo M, Villanueva R, Cirauqui B, Vázquez S, Fernández A, Recalde S, Vethencourt A, Soler T, Pérez-Martín X, Gil-Gil M. Impact of oncotype dx genetic signature used in early breast cancer. Clinical and economic analisys of a 110 patient cohort treated in the Catalan Oncologic Institute (ICO), Spain [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 P5-15-09.

Does multilocus inherited neoplasia alleles syndrome have severe clinical expression?

IMPORTANCE

Genetic testing of hereditary cancer using comprehensive gene panels can identify patients with more than one pathogenic mutation in high and/or moderate-risk-associated cancer genes. This phenomenon is known as multilocus inherited neoplasia alleles syndrome (MINAS), which has been potentially linked to more severe clinical manifestations.

OBJECTIVE

To determine the prevalence and clinical features of MINAS in a large cohort of adult patients with hereditary cancer homogeneously tested with the same gene panel.

PATIENTS AND METHODS

A cohort of 1023 unrelated patients with suspicion of hereditary cancer was screened using a validated panel including up to 135 genes associated with hereditary cancer and phakomatoses.

RESULTS

Thirteen (1.37%) patients harbouring two pathogenic mutations in dominant cancer-predisposing genes were identified, representing 5.7% (13/226) of patients with pathogenic mutations. Most (10/13) of these cases presented clinical manifestations associated with only one of the mutations identified. One case showed mutations in MEN1 and MLH1 and developed tumours associated with both cancer syndromes. Interestingly, three of the double mutants had a young age of onset or severe breast cancer phenotype and carried mutations in moderate to low-risk DNA damage repair-associated genes; two of them presented biallelic inactivation of CHEK2. We included these two patients for the sake of their clinical interest although we are aware that they do not exactly fulfil the definition of MINAS since both mutations are in the same gene.

CONCLUSIONS AND RELEVANCE

Genetic analysis of a broad cancer gene panel identified the largest series of patients with MINAS described in a single study. Overall, our data do not support the existence of more severe manifestations in double mutants at the time of diagnosis although they do confirm previous evidence of severe phenotype in biallelic CHEK2 and other DNA repair cancer-predisposing genes.

A phase 2 trial of neoadjuvant metformin in combination with trastuzumab and chemotherapy in women with early HER2-positive breast cancer: the METTEN study

The METTEN study assessed the efficacy, tolerability, and safety of adding metformin to neoadjuvant chemotherapy plus trastuzumab in early HER2-positive breast cancer (BC). Women with primary, non-metastatic HER2-positive BC were randomized (1:1) to receive metformin (850 mg twice-daily) for 24 weeks concurrently with 12 cycles of weekly paclitaxel plus trastuzumab, followed by four cycles of 3-weekly FE75C plus trastuzumab (arm A), or equivalent regimen without metformin (arm B), followed by surgery. Primary endpoint was the rate of pathological complete response (pCR) in the per-protocol efficacy population. pCR rate was numerically higher in the metformin-containing arm A (19 of 29 patients [65.5%, 95% CI: 47.3-80.1]) than in arm B (17 of 29 patients [58.6%, 95% CI: 40.7-74.5]; OR 1.34 [95% CI: 0.46-3.89], P = 0.589). The rate of breast-conserving surgery was 79.3% and 58.6% in arm A and B (P = 0.089), respectively. Blood metformin concentrations (6.2 μmol/L, 95% CI: 3.6-8.8) were within the therapeutic range. Seventy-six percent of patients completed the metformin-containing regimen; 13% of patients in arm A dropped out because of metformin-related gastrointestinal symptoms. The most common adverse events (AEs) of grade ≥3 were neutropenia in both arms and diarrhea in arm A. None of the serious AEs was deemed to be metformin-related. Addition of anti-diabetic doses of metformin to a complex neoadjuvant regimen was well tolerated and safe. Because the study was underpowered relative to its primary endpoint, the efficacy data should be interpreted with caution.

Tumor xenograft modeling identifies an association between TCF4 loss and breast cancer chemoresistance

Understanding the mechanisms of cancer therapeutic resistance is fundamental to improving cancer care. There is clear benefit from chemotherapy in different breast cancer settings; however, knowledge of the mutations and genes that mediate resistance is incomplete. In this study, by modeling chemoresistance in patient-derived xenografts (PDXs), we show that adaptation to therapy is genetically complex and identify that loss of transcription factor 4 (TCF4; also known as ITF2) is associated with this process. A triple-negative BRCA1-mutated PDX was used to study the genetics of chemoresistance. The PDX was treated in parallel with four chemotherapies for five iterative cycles. Exome sequencing identified few genes with de novo or enriched mutations in common among the different therapies, whereas many common depleted mutations/genes were observed. Analysis of somatic mutations from The Cancer Genome Atlas (TCGA) supported the prognostic relevance of the identified genes. A mutation in TCF4 was found de novo in all treatments, and analysis of drug sensitivity profiles across cancer cell lines supported the link to chemoresistance. Loss of TCF4 conferred chemoresistance in breast cancer cell models, possibly by altering cell cycle regulation. Targeted sequencing in chemoresistant tumors identified an intronic variant of TCF4 that may represent an expression quantitative trait locus associated with relapse outcome in TCGA. Immunohistochemical studies suggest a common loss of nuclear TCF4 expression post-chemotherapy. Together, these results from tumor xenograft modeling depict a link between altered TCF4 expression and breast cancer chemoresistance.

Summary: By modeling chemoresistance in patient-derived breast cancer xenografts, this study shows that adaptation to therapy is genetically complex and that loss of transcription factor 4 (TCF4) is associated with this process.

Abstract P2-09-11: PAM50 intrinsic subtyping as a predictor of pathological complete response to neoadjuvant trastuzumab-based chemotherapy in early HER2-positive breast cancer

Background: HER2-positive breast cancer (BC) is a heterogeneous disease from a clinical and biological perspective. Intrinsic subtype defined by gene expression has an important role in determining response to treatment, as seen in several neoadjuvant trials (e.g. CALGB40601, CherLOB, NeoALTTO and PAMELA). However, limited data exist in an off-trial setting. The objective of this study was to evaluate the association of intrinsic subtypes with pathological completed response (pCR) and survival outcomes of a series of HER2-positive patients (pts) homogeneously treated with trastuzumab-based primary chemotherapy (PC) in a single comprehensive cancer center.

Methods: Clinical-pathological data were evaluated in a series of 150 consecutive stage II-IIIC (T4d included) HER2-positive BC pts treated in ICO-Hospitalet (Spain) from August-2009 to December-2012 with weekly paclitaxel x12 followed by FEC/3w x 4 and concurrent trastuzumab for a total of 24w. HER2-positivity was considered according to ASCO-CAP 2007 guidelines. pCR was defined as ypT0/isypN0. The expression of 105 BC-related genes, including the PAM50 genes, was determined in baseline and residual formalin-fixed paraffin-embedded tumor samples using the nCounter platform. Intrinsic subtypes were determined by the research-based PAM50 gene expression predictor. Association of variables with pCR or disease-free survival (DFS) was evaluated using logistic regression analyses and cox proportional hazard models.All statistical tests were two-sided and considered significant when p≤0.05.

Results: Most pts had T2 (64%) and T4 (20%) tumors and clinically node-positive disease (77%). 53% had hormonal receptor (HR)+ disease. 84 of the 150pts (56%) achieved a pCR; HR-neg was associated with higher pCR rates (72.5%vs 42% in HR+ P&lt;0.001). 90 of the 150 (60%) baseline samples were evaluated. Baseline subtype distribution: HER2-enriched (HER2-E) 63%, Luminal A 11%, Basal-like 8.9%, Normal-like 8.9% and Luminal B 7.8%. Although HER2-E predominated in HR-neg tumors (74%), 53% of HR+ tumors were HER2-E. pCR rates varied according to intrinsic subtype (P&lt;0.001). HER2-E tumors were associated with higher pCR rates compared to non-HER2-E (68.4% vs 33.3%, P&lt;0.001) regardless HR-status. Five of the 8 PAM50 signatures (HER2E, ROR-S, ROR-P, Basal-like and Proliferation score) were associated with pCR, whereas Luminal A was associated with no-pCR (P&lt;0.001). With a median follow-up of 6.6 years, HER2-E subtype was associated with a better DFS compared to non-HER2-E (5-year DFS 92.4% vs 75.9%; HR= 0.27; 95% CI 0.08-0.91; P=0.034). Finally, 28 of the 66 (42.4%) surgical specimens with residual disease were studied. Residual subtype distribution was: Normal-like (50.0%), Luminal A (32.1%), HER2-E (14.3%) and Luminal B (3.5%).

Conclusions: In this consecutive series of HER2-positive BCtreated homogeneously with neoadjuvant trastuzumab-based PC, all of the main intrinsic molecular subtypes were identified with a predominance of HER2-E. HER2-E was significantly associated with pCR and survival outcome. Distribution of the intrinsic subtypes in residual disease differed from untreated tumors.

Citation Format: Pernas S, Petit A, Climent F, Pare L, Perez-Martin J, Ventura L, Galvan P, Falo C, Morilla I, Fernandez-Ortega A, Stradella A, Pascual T, Gil-Gil M, Prat A. PAM50 intrinsic subtyping as a predictor of pathological complete response to neoadjuvant trastuzumab-based chemotherapy in early HER2-positive breast cancer [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 P2-09-11.

Abstract P5-21-23: Evaluation of the drug interaction potential of palbociclib and exemestane – Results from the PEARL pharmacokinetic sub-Study

Background: Palbociclib (PAL) is an oral cyclin-dependent kinase (CDK) 4/6 inhibitor that is under investigation in multiple oncologic clinical trials and is currently approved for use in combination with aromatase inhibitors (AIs) or fulvestrant (FUL) in patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2–) advanced breast cancer (BC).

The PEARL Study is an ongoing international, open label, controlled, randomized Phase 3 study comparing the efficacy and safety of PAL in combination with endocrine therapy (exemestane [EXE] or FUL) versus capecitabine in postmenopausal women with HR+/ HER2– metastatic BC whose disease progressed on AIs. A secondary objective of the study was to evaluate the pharmacokinetics (PK) of PAL (125mg QD, 3 weeks on/1 week off) and EXE (25mg QD, continuously) when coadministered. This is the first study to investigate the drug-drug interaction (DDI) potential of the combination of PAL and the AI EXE.

Methods: Patients (pts) randomized to the PAL+EXE arm of the PEARL Study in seven selected sites had the option of participating in the PK sub-study. Those who enrolled in the PK sub-study received EXE alone in a 7-day lead-in period immediately prior to Cycle 1 Day 1, when both drugs were coadministered on their standard dosing regimens. Sub-study pts were to have 2 pre-dose plasma PK samples drawn at steady-state (ss) during the lead-in period ("EXE Alone") for EXE determination, and 2 ss PK samples drawn for EXE and PAL determination (2 per analyte) during coadministration ("PAL+EXE"). Plasma concentrations of PAL and EXE were measured using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. The withinpatient mean concentration of the PK samples which met ss acceptance criteria (WPM-Ctrough) for each analyte were generated for each treatment period as the input for DDI analyses.

To assess the effect of coadministration of PAL on EXE PK, the WPM-Ctrough of EXE was compared within patients between the "PAL+EXE" (Test) and "EXE Alone" (Reference) treatment periods using a one-way analysis of variance (ANOVA) model with treatment as a fixed effect and patient as a random effect. To assess the effect of coadministration of EXE on PAL PK, the WPM-Ctrough of PAL was compared between the "PAL+EXE" period (Test) and historical data (Reference) using an ANOVA model. Analysis of covariance (ANCOVA) models were used to assess the impact of demographic differences between analysis populations in covariates known to impact PAL PK on the ANOVA model conclusions.

Results: A total of 26 pts randomized to the PAL+EXE arm were enrolled in the PK sub-study and had PK samples analysed, of which 23 meet ss acceptance criteria. The ratio of the adjusted geometric means for EXE WPM-Ctrough was 106.9% (90%CI: 82.4-138.8), when EXE was administered with PAL, compared with its administration alone. Likewise, the models to assess potential for EXE to perpetrate DDI on PAL PK showed ratios of adjusted geometric means of 102.4% (90%CI: 82.0-127.9) and 111.6% (90%CI: 90.3137.8), when adjusted for covariates.

Conclusion: The PK data indicate a lack of a clinically meaningful DDI between PAL and EXE when the 2 drugs are coadministered.

Sponsor: GEICAM

Citation Format: Martín M, Hoffman J, Ruiz-Borrego M, Muñoz M, Calvo L, Crownover P, García-Sáenz JA, Alba E, Wang D, Thallinger C, Stradella A, Montaño Á, Adamo B, Antolín S, Moreno-Antón F, Falo C, Ruiz V, Martín N, Caballero R, Carrasco E, Gil-Gil M. Evaluation of the drug interaction potential of palbociclib and exemestane – Results from the PEARL pharmacokinetic sub-Study [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 P5-21-23.

Efficacy of taxanes followed by anthracyclines as neoadjuvant therapy in HER2-negative breast cancer (BC): Analysis of everyday clinical practice

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Background: Pathological complete response (pCR) after neoadjuvant chemotherapy for BC has been related with survival, and the sequence of anthracyclines followed by taxanes (AT) has been the strategy to achieve this response. Some studies suggest that the reverse sequence (TA) might improve cancer outcomes. The aim of our study was to compare clinical response, toxicity and efficacy in terms of pCR rate (ypT0/pTis, ypN0) between both sequences Methods: A retrospective cohort study was designed. TA cohort received Docetaxel (100 mg/m2) x 4, followed by AC (60/600 mg/m2) x 4. AT cohort received the reverse sequence at the same doses. To be included, it was necessary to have received at least one cycle in the planned sequence. Logistic regression analysis was performed to obtain a model adjusted by age, menopausal status, tumor size, nodal status, grade, estrogen receptor (ER), progesterone receptor, and Ki67 Results: From June 2008 to December 2015, 135 consecutive patients with stage II – III HER2 negative BC were treated: TA (n = 48) and AT (n = 87). No significant differences in patient characteristics between groups were found, except for histological grade 3 (63.2% to AT vs. 35.4% to TA), and ER negative (41.4% to AT vs. 22.9% to TA). The pCR rate for TA was 16.7% (8 of 40) vs. 14.9% (13 of 74) for AT. Multivariate logistic regression analysis found OR = 3.65 to achieve pCR for TA (95%CI 1.03 – 12.94; p = .045). We also performed the same analysis for two clinical parameters of response: Neoadjuvant response index (NRI) with cut-off > 0.5 (OR 3.96, 95%CI 1.42-11.08; p = .009) and Clinical response (CR) > 50% (OR 3.65, 95%CI 1.03 – 12.94; p = .045). These parameters were correlated in our series with DFS (p = .011 to NRI and p = .00023 to CR) and OS (p = .034 to NRI and p = .0014 to CR) using the Kaplan-Meier method. No significant differences between rates of either, hospitalizations, neutropenia or dose intensity were found Conclusions: Sequence of T followed by A was slightly significantly more effective to achieve pCR as well as better clinical outcomes in our series of HER2 negative BC than classical sequence of A followed by T, and support the design of large prospective studies to confirm these results

Abstract P4-21-32: Treatment of early HER2-positive breast cancer in trastuzumab era in everyday clinical practice: An overview after 10 years of its approval

Introduction: The addition of Trastuzumab(T) to chemotherapy (CT) revolutionized HER2-positive breast cancer(BC) and changed its natural history. We reviewed the efficacy of T outside clinical trials in a cancer comprehensive center.

Methods: Ambiespective and descriptive study was conducted in Catalan Institute of Oncology (ICO-Barcelona). Estimates of progression-free survival (PFS) and overall survival (OS) were obtained with the Kaplan-Meier method and compared with LogRank test. The association of clinic-pathological variables and outcome was studied by χ2and Cox proportional hazard analysis.

Results: 430 consecutive early HER2-positive BC patients (pts) were treated with adjuvant/neoadjuvant T and CT from Jan 2005 to Dec 2012. Pt basal characteristics are reported in Table 1. Neoadjuvant treatment was administrated in 230pts (54%) and in 200 (46%) in adjuvancy. Pathological complete response (pCR) in breast and nodes (ypT0/isypN0) was achieved in 48% of pts, with higher rates in hormone receptor (HR)-negative pts (62 vs 37% p=0.0005). Median duration of T: 10.6 months (m). 28%pts treated with neoadjuvant T+CT who achieved a pCR did not receive adjuvant T. Treatment discontinuation: 38pts (8.8%): 27pts due to cardiac toxicity and 4 relapsed during adjuvant T. In 87%pts, neoadjuvant CT was based on anthracyclines(A) and taxanes. Adjuvant CT: A and taxanes in 57.4%; 14%pts FAC, 15.4% A-CMF and 12% TCH. At a median follow-up of 70m (3-135), 44pts (10.4%) had relapsed: 33pts with distant M1, 9pts with only loco-regional disease and 2pts contralateral HER2-positive BC. M1 location: 46% visceral, 34% bone/lymph nodes and 20% in central nervous system (CNS). PFS was 23.4m(0-88); median OS was not reached; estimated 10 years-OS was 86.5%. Pts treated with A and taxanes had a significantly better OS compared to those treated with other CT (113 vs 98m, p= 0.009). Kaplan-Meier curve showed numerically higher relapses at 10 years in HR-positive pts (83 vs 90% p=0.8). Pts with pCR had significantly better OS (113 vs 104m, p=0.006). Pts with CNS-metastases had a significantly worse OS (13 vs 26m,p=0,02) and those with HR-negative (49 vs 24m, p= 0.033).

Conclusion: In everyday clinical practice, recurrences after adjuvant/neoadjuvant trastuzumab in HER2-positive BC were less than described in the T-pivotals trials, with 10% of recurrences at a median of FU of 70m. In our series, estimated 10 years-OS was 86.5%. Pts treated with A and taxanes had a significantly better OS as well as those pts who achieved a pCR. On the contrary, pts with CNS M1 and those with HR-negative had worse prognosis.

Table 1Median age51.9y (27-83)Stage I/II/III106 (25%)/ 226 (52%)/ 97 (23%)HR Positive/ Negative249 (58%)/181 (42%)

Citation Format: Ortega A, Domenech M, Falo C, Gil M, Stradella A, Fernandez A, Morilla I, Villanueva R, Castany R, Vazquez S, Molina K, Bergamino M, Navarro V, Pernas S. Treatment of early HER2-positive breast cancer in trastuzumab era in everyday clinical practice: An overview after 10 years of its approval [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 P4-21-32.

Lytic lesions in a patient with past history of renal cancer

OBJECTIVE

To study lytic lesions in a patient with past history of renal cancer.

METHODS

A 62 year-old man was admitted to hospital for investigation of the cause of polyostotic bone pain.

RESULTS

Brown tumors due to hyperparathyroidism turned out to be the cause of bone pain.

CONCLUSIONS

Differential diagnosis is important in daily practice in order to provide a correct treatment for each condition.

Progressive increasing in the risk of second and subsequent malignant tumors in patients with a head and neck cancer: A validation study with SEER data

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Background: Patients with a head and neck squamous cell carcinoma (HNSCC) index tumor have a increased risk (2-4% per year) for appearance of a second malignant neoplasms (SMN) and higher risk for successive malignant tumors during the follow-up. The objective of our study was to validate this concept with data of patients included in the Surveillance Epidemiology and End Results (SEER) program (1973-2008). Methods: We performed a population-based cohort study of 149.328 patients with a primary oral cavity, oropharynx, hypopharynx and larynx squamous cell carcinoma index tumor, included in the SEER program, to analize the actuarial survival-free of second and successive tumors. A total of 11.948 (8%) patients had one or more malignant tumors before the diagnosis of HNSCC. Results: During the follow-up period, a total of 31.507 new SMN appeared. There was a progressive and significant increase in the risk of SMN. The annual hazard ratio for 2nd to 7th successive SMN was 2.3%, 2.7%, 3.9%, 5.4%, 8.9% and 19.1% annual risk respectively. Additionally 11 patients had 8th SMN. We observed a progressive increase in the risk of appearence of new malignant tumors located in and outside the aerodigestive tract. The increase in the risk of SMN was higher for tumors located in the aerodigestive tract than tumors located outside aerodigestive tract. It was a tendency towards the increase in the proportion of HNSCC with the appearance of new tumors, with a decrease in the proportion of the malignant tumors located in the lung and in locations outside the aerodigestive tract. There were significant differences inthe risk of SMN between second and third, third and fourth, fourth and fifth, and sist and seventh tumors (p<0.0001). Conclusions: In patients with HNSCC there is a progressive increase in the risk of appearance of successive tumors. Previous tobacco and alcohol consumption, persistence in the exposure to carcinogens and individual susceptibility (genetic) could play a role in the increased risk of SMN. We have validated this concept with data from the SEER program.

Prognostic value of BRAF and KRAS mutations in colorectal cancer patients

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Background: KRAS mutation has been established as a predictive marker of resistance to antiEGFR therapy in patients (pts) with colorectal cancer (CRC) but the role of BRAF is not yet clear. Both gene mutations have also been studied as prognostic factors but results are contradictory. AntiEGFR therapies impair evaluation of KRAS and BRAF as prognostic factors when overall survival is an endpoint. We hypothesized that if KRAS or BRAF were prognostic factors, they would influence time to relapse (TTR) after complete tumor resection. Methods: Patients who underwent surgery between 2007 and 2011 for stage II and III CRC were retrieved from our database. Codon 12 and 13 KRAS mutations and V600E BRAF mutation were analyzed. Clinical characteristics and mutation status were correlated with TTR. Results: We analyzed 170 pts with a median age of 66 (26 – 86) years. Tumors were located in the right colon in 27% of pts, in the transverse colon in 3%, in the left colon in 41%, and in the rectum in 29%. Most (55.3%) were stage III; 59% received adjuvant chemotherapy. KRAS and BRAF mutations were present in 66 (38.8%) and 5 (2.9%) pts respectively, and both were mutually exclusive. The most frequent KRAS mutations were: G12D (39.3%), G12V (27.2%), G13D (15.1%). Median TTR was 71 weeks (w) (95% CI 63-79). V600E BRAF mutation was the only factor associated with TTR. TTR was 42 w in tumors with the BRAF mutation and 74 w in wild-type tumors (p=0.041). Among KRAS mutations, KRAS G12V conferred a significantly longer TTR (100w) than the other subtype mutations (69 w; p=0.05). Conclusions: Our results suggest that V600E BRAF mutation is a negative prognostic factor in CRC, conferring a shorter time to relapse. Additionally, the KRAS G12V determines a different behavior among KRAS mutation tumors.

Testosterone levels as a prognostic factor for survival in patients with castrate-restistant prostate cancer (CRPC)

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Background: To analyze the prognostic value for survival of the absolute levels of serum testosterone in patients under the definition of CRPC (PSA and/or clinical progression with a testosterone level below 50 ng/dL). Methods: 49 patients were included in 4 non-hormonal first line phase II-III trials in our institution since August 2006 until Jan 2012 for metastatic CRPC. Inclusion criteria of those trials uniformly required castrate levels of testosterone. Survival was calculated since the date of entrance in the trial. Results: Median age was 71 years (53-89). 9/49 (18%) of the patients had visceral metastases. Median PSA was 66.7 U/L (0.1-936). Median testosterone level was 11.54 ng/dL (range 0.2-49.9). All patients had metastatic prostate cancer, previous treatment consisted of at least 2 hormonal maneuvers (adding or stopping antiandrogen for a wash-up period of 42 days for bicalutamide). All patients received at least one line of chemotherapy for CRPC as part of the trial or after the completion of the trial. Median survival was 21.85 months. For 26 patients with a serum testosterone level below the median value, median survival was 17 months and 35.45 months for those patients with a testosterone level over 11.51 ng/dL (p value 0.036). Conclusions: Testosterone serum levels even under castration level (below 50 ng/dL) were a prognostic factor for survival in patients with metastatic prostate cancer considered castration resistant.