Disease Extent in Stage IV Lobular Carcinoma: the Aid of Imaging and Liquid Biopsy Analyses

Summary

Metastatic invasive lobular carcinoma (ILC) is a distinct breast cancer subtype characterized by loss of E-cadherin and a diffuse growth pattern that makes metastases difficult to detect with standard imaging such as computed tomography (CT) or 18F-Fluorodeoxyglucose Positron Emission Tomography (18F-FDG PET)/CT. As a result, disease burden in patients with ILC is frequently underestimated, progression is identified later than clinically optimal, and many patients are excluded from clinical trials due to insufficiently measurable disease.

Whole-body diffusion-weighted magnetic resonance imaging (WB-DWI/MRI) is a radiation-free imaging technique that has demonstrated improved sensitivity for detecting metastases-including peritoneal, bone, and nodal disease-in ILC. Retrospective studies suggest that WB-DWI/MRI can identify clinically relevant progression not visible on standard imaging. However, prospective evidence in ILC is lacking. Circulating tumor DNA (ctDNA) has also shown promise as a minimally invasive biomarker for monitoring treatment response, with early molecular changes often preceding radiologic progression, but data specific to ILC remain limited.

The DELILA study is a prospective, multicenter clinical trial conducted at University Hospitals Leuven and Institut Jules Bordet. The study aims to enroll 43 patients starting first-line systemic therapy for metastatic hormone receptor positive human epidermal growth factor receptor 2 negative (HR+/HER2-) ILC. Participants undergo serial dual imaging-WB-DWI/MRI and standard-of-care imaging-at baseline, at 1 month, and approximately every 3 months for up to 30 months or until disease progression. At each imaging time point, blood samples are collected for ctDNA analysis and Ca15.3 tumor marker assessment. Patient-reported psychological burden related to repeated imaging and blood sampling is evaluated using validated questionnaires.

The primary objective is to assess the added value of WB-DWI/MRI in detecting disease progression that informs clinical decision-making compared to standard imaging. Secondary objectives include evaluating whether ctDNA or Ca15.3 dynamics reflect disease evolution, assessing measurability of lesions with Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 and MRI-specific criteria, identifying early biomarkers of treatment response using Apparent Diffusion Coefficient (ADC) changes and ctDNA kinetics, and characterizing the psychological impact of trial procedures.

This study will provide the first adequately powered prospective evidence on the clinical utility of WB-DWI/MRI and liquid biopsy monitoring in metastatic ILC. Results may support implementation of WB-DWI/MRI as a routine imaging strategy, guide imaging frequency through biomarker-informed approaches, and improve patient experience and trial eligibility for individuals living with metastatic ILC.

Conditions

• Invasive Lobular Breast Carcinoma

Interventions

DIAGNOSTIC_TEST

whole body diffusion weighted MRI

Frequency: at baseline, after 1 month and every 3 months until 30 months of follow-up or disease progression

DIAGNOSTIC_TEST

ctDNA

Frequency: at baseline, after 1 month and every 3 months until 30 months of follow-up or disease progression

Sponsors & Collaborators

• Jules Bordet Institute

  collaborator OTHER

• KU Leuven

  lead OTHER

Principal Investigators

• Hans Wildiers, MD/PHD · UZ Leuven

• Philippe Aftimos, MD · Jules Bordet Institute

• Elia Biganzoli, PHD · University of Milan

Study Design

Allocation

NA

Purpose

DIAGNOSTIC

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-07-01

Primary Completion

2030-06-30

Completion

2030-06-30