Clinicopathological and molecular predictors of [F]FDG-PET disease detection in HER2-positive early breast cancer: RESPONSE, a substudy of the randomized PHERGain trial.

Background: The PHERGain study (NCT03161353) is assessing early metabolic responses to neoadjuvant treatment with trastuzumab-pertuzumab and chemotherapy de-escalation using a [Fluorine]fluorodeoxyglucose-positron emission tomography ([F]FDG-PET) and a pathological complete response-adapted strategy in HER2-positive (HER2+) early breast cancer (EBC). Herein, we present RESPONSE, a PHERGain substudy, where clinicopathological and molecular predictors of [F]FDG-PET disease detection were evaluated.

Methods: A total of 500 patients with HER2 + EBC screened in the PHERGain trial with a tumor size > 1.

3-year invasive disease-free survival with chemotherapy de-escalation using an F-FDG-PET-based, pathological complete response-adapted strategy in HER2-positive early breast cancer (PHERGain): a randomised, open-label, phase 2 trial.

Background: PHERGain was designed to assess the feasibility, safety, and efficacy of a chemotherapy-free treatment based on a dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab in patients with HER2-positive early breast cancer (EBC). It used an fluorine-fluorodeoxyglucose-PET-based, pathological complete response (pCR)-adapted strategy.

Methods: PHERGain was a randomised, open-label, phase 2 trial that took place in 45 hospitals in seven European countries.

Optimal [F]FDG PET/CT Cutoff for Pathologic Complete Response in HER2-Positive Early Breast Cancer Patients Treated with Neoadjuvant Trastuzumab and Pertuzumab in the PHERGain Trial.

The PHERGain trial investigated the potential of metabolic imaging to identify candidates for chemotherapy deescalation in human epidermal growth factor receptor 2 (HER2)-positive, invasive, operable breast cancer with at least 1 breast lesion evaluable by [F]FDG PET/CT. [F]FDG PET/CT responders were defined as patients with an SUV reduction (ΔSUV) of at least 40% in all of their target lesions after 2 cycles of trastuzumab and pertuzumab (HP) (with or without endocrine therapy). In total, 227 of 285 patients (80%) included in the HP arm showed a predefined metabolic response and received a total of 8 cycles of HP (with or without endocrine therapy).

Molecular imaging predicts lack of T-DM1 response in advanced HER2-positive breast cancer (final results of ZEPHIR trial).

Efficacy of the human epidermal growth factor receptor (HER)2-targeting trastuzumab emtansine (T-DM1) in breast cancer (BC) relies on HER2 status determined by immunohistochemistry or fluorescence in-situ hybridization. Heterogeneity in HER2 expression, however, generates interest in "whole-body" assessment of HER2 status using molecular imaging. We evaluated the role of HER2-targeted molecular imaging in detecting HER2-positive BC lesions and patients unlikely to respond to T-DM1.

copy-number gain and inhibitors of the PI3K/AKT/mTOR pathway in triple-negative breast cancer.

As wider insights are gained on the molecular landscape of triple-negative breast cancer (TNBC), novel targeted therapeutic strategies might become an option in this setting as well. Activating mutations of represent the second most common alteration in TNBC after the mutation, with a prevalence of ∼10%-15%. Considering the well-established predictive role of mutations for response to agents targeting the PI3K/AKT/mTOR pathway, several clinical trials are currently evaluating these drugs in patients with advanced TNBC.

[18F]FDG and [18F]FES PET/CT Imaging as a Biomarker for Therapy Effect in Patients with Metastatic ER+ Breast Cancer Undergoing Treatment with Rintodestrant.

Purpose: PET with 16α-[18F]-fluoro-17β-estradiol ([18F]FES) allows assessment of whole body estrogen receptor (ER) expression. The aim of this study was to investigate [18F]-fluorodeoxyglucose ([18F]FDG) and [18F]FES PET/CT imaging for response prediction and monitoring of drug activity in patients with metastatic ER-positive breast cancer undergoing treatment with the selective estrogen receptor downregulator (SERD) rintodestrant.

Experimental Design: In this trial (NCT03455270), PET/CT imaging was performed at baseline ([18F]FDG and [18F]FES), during treatment and at time of progression (only [18F]FES).

Serum thymidine kinase activity in patients with hormone receptor-positive and HER2-negative metastatic breast cancer treated with palbociclib and fulvestrant.

Background: Biomarkers for cyclin-dependent kinase 4/6 inhibitors, such as palbociclib, for patients with hormone receptor-positive/HER2-negative metastatic breast cancer are lacking. Thymidine kinase is a proliferation marker downstream of the cyclin-dependent kinase 4/6 pathway. We prospectively investigated the prognostic role of serum thymidine kinase activity (sTKa), in patients treated with Palbociclib + fulvestrant.

FDG positron emission tomography imaging and ctDNA detection as an early dynamic biomarker of everolimus efficacy in advanced luminal breast cancer.

Biomarkers to identify patients without benefit from adding everolimus to endocrine treatment in metastatic breast cancer (MBC) are needed. We report the results of the Pearl trial conducted in five Belgian centers assessing F-FDG-PET/CT non-response (n = 45) and ctDNA detection (n = 46) after 14 days of exemestane-everolimus (EXE-EVE) to identify MBC patients who will not benefit. The metabolic non-response rate was 66.

Chemotherapy de-escalation using an F-FDG-PET-based pathological response-adapted strategy in patients with HER2-positive early breast cancer (PHERGain): a multicentre, randomised, open-label, non-comparative, phase 2 trial.

Background: Several de-escalation approaches are under investigation in patients with HER2-positive, early-stage breast cancer. We assessed early metabolic responses to neoadjuvant trastuzumab and pertuzumab using F-fluorodeoxyglucose (F-FDG)-PET (F-FDG-PET) and the possibility of chemotherapy de-escalation using a pathological response-adapted strategy.

Methods: We did a multicentre, randomised, open-label, non-comparative, phase 2 trial in 45 hospitals in Spain, France, Belgium, Germany, the UK, Italy, and Portugal.

How COVID-19 pandemic affected cancer progression: Three different scenarios evidenced by PET imaging.

COVID-19 pandemic is having a strong impact on healthcare providers around the world, by refocusing and reducing non-essential medical activities. Nuclear medicine departments among others, have been reorganizing and reprioritizing diagnostic and theragnostic procedures. This reorganizing had a negative impact on the supply of positron emission tomography (PET) services to oncologic patients, whose health was affected.

Mechanisms of resistance to trastuzumab emtansine (T-DM1) in HER2-positive breast cancer.

The HER2-targeted antibody-drug conjugate trastuzumab emtansine (T-DM1) is approved for the treatment of metastatic, HER2-positive breast cancer after prior trastuzumab and taxane therapy, and has also demonstrated efficacy in the adjuvant setting in incomplete responders to neoadjuvant therapy. Despite its objective activity, intrinsic and acquired resistance to T-DM1 remains a major clinical challenge. T-DM1 mediates its activity in a number of ways, encompassing HER2 signalling blockade, Fc-mediated immune response and payload-mediated microtubule poisoning.

Added value of para-aortic surgical staging compared to F-FDG PET/CT on the external beam radiation field for patients with locally advanced cervical cancer: An ONCO-GF study.

Objective: Extended field chemoradiation is recommended for patients with locally advanced cervical cancer (LACC) and para-aortic lymph node (PALN) metastases. The radiation planning may be based on PET/CT while others recommend to rely on surgical staging. We report the rate of patients for whom the radiation field defined on PET/CT was modified by the histological PALN status.

Tumor Drug Penetration Measurements Could Be the Neglected Piece of the Personalized Cancer Treatment Puzzle.

Precision medicine aims to use patient genomic, epigenomic, specific drug dose, and other data to define disease patterns that may potentially lead to an improved treatment outcome. Personalized dosing regimens based on tumor drug penetration can play a critical role in this approach. State-of-the-art techniques to measure tumor drug penetration focus on systemic exposure, tissue penetration, cellular or molecular engagement, and expression of pharmacological activity.

Strategies and technical challenges for imaging oligometastatic disease: Recommendations from the European Organisation for Research and Treatment of Cancer imaging group.

Patients with oligometastatic disease (OMD) often have controllable symptoms, and cures are possible. Technical improvements in surgery and radiotherapy have introduced the option of metastasis-directed ablative therapies as an adjunct or alternative to standard-of-care systemic therapies. Several clinical trials and registries are investigating the benefit of these therapeutic approaches across several cancer sites.

N-Acetylcysteine breaks resistance to trastuzumab caused by MUC4 overexpression in human HER2 positive BC-bearing nude mice monitored by Zr-Trastuzumab and F-FDG PET imaging.

Trastuzumab remains an important drug in the management of human epidermal growth factor receptor 2 (HER2) overexpressing breast cancer (BC). Several studies reported resistance mechanisms to trastuzumab, including impaired HER2-accessibility caused by mucin 4 (MUC4). Previously, we demonstrated an increase of Zirconium-89-radiolabeled-trastuzumab (Zr-Trastuzumab) accumulation when MUC4-overexpressing BC-cells were challenged with the mucolytic drug N-Acetylcysteine (NAC).

HER2-positive breast cancer is lost in translation: time for patient-centered research.

No biomarker beyond HER2 itself, which suffers from a low positive predictive value, has demonstrated clinical utility in breast cancer, despite numerous attempts to improve treatment tailoring for the growing number of anti-HER2 targeted therapies. This prompted us to examine the body of evidence, using a systematic approach, to identify putative predictive biomarkers in HER2-positive breast cancer, and discuss the hitherto failure to address the needs of patients. In the future, it is hoped immune-based biomarkers will predict benefit from anti-HER2 treatments in the neoadjuvant and adjuvant settings.

Imaging Diagnostic and Therapeutic Targets: Human Epidermal Growth Factor Receptor 2.

Since the approval of trastuzumab, a humanized monoclonal antibody against the extracellular domain of human epidermal growth factor receptor 2 (HER2), 3 other HER2-targeting agents have gained regulatory approval: lapatinib, pertuzumab, and trastuzumab-emtansine. These agents have revolutionized the management of HER2-positive breast cancer, highlighting the concept that targeted therapies are successful when patients exhibit tumor-selective expression of a molecular target-in this case, HER2. However, response prediction and innate or acquired resistance remain serious concerns.

18F-FDG PET/CT for early prediction of response to neoadjuvant lapatinib, trastuzumab, and their combination in HER2-positive breast cancer: results from Neo-ALTTO.

Unlabelled: Molecular imaging receives increased attention for selecting patients who will benefit from targeted anticancer therapies. Neo-ALTTO (Neoadjuvant Lapatinib and/or Trastuzumab Treatment Optimisation) enrolled 455 women with invasive human epidermal growth factor receptor 2 (HER2)-positive breast cancer and compared rates of pathologic complete response (pCR) to neoadjuvant lapatinib, trastuzumab, and their combination. Each anti-HER2 therapy was given alone for 6 wk, followed by 12 wk of the same therapy plus weekly paclitaxel.

Circulating tumor cells and response to neoadjuvant paclitaxel and HER2-targeted therapy: a sub-study from the NeoALTTO phase III trial.

Background: The role of circulating tumor cells (CTCs) in HER2-positive breast cancer patients receiving neoadjuvant therapy is unclear.

Patients & Methods: We describe the CTC detection rate, HER2 phenotyping and pathological complete response (pCR) in patients enrolled in the NeoALTTO phase III trial. Participation in the CTC sub-study was optional.

New PET imaging agents in the management of solid cancers.

Purpose Of Review: (18)F-fluoro-2-deoxy-D-glucose PET-computed tomography (CT) has a major clinical impact in oncology not only for diagnostics but also for staging, response assessment, and relapse detection. However, several other PET tracers are needed for a more complete molecular characterization of cancers which has great importance in the era of individualized targeted therapies. PET-CT is an exquisite tool for molecular imaging because it allows detection of nanomolar quantities of tracer molecules targeting different hallmarks of cancer.

WITHDRAWN:New PET imaging agents in the management of solid cancers.

Ahead of Print article withdrawn by publisher.