Added Value of Preoperative Contrast Enhanced Mammography in Staging of Malignant Breast Lesions (PROCEM): A Randomized Controlled Trial

Abstract

Background: Contrast-enhanced mammography (CEM) is increasingly used in breast cancer diagnostics. This is the first randomised trial assessing the additional value of CEM in preoperative staging of breast cancer.Method: This prospective randomised controlled trial, with two arms and a 1:1 allocation ratio, was performed at two hospitals in Sweden. In all, 440 patients with breast cancer, scheduled for primary surgery, were randomised to preoperative CEM or not (control). The primary outcome measure was a 10% treatment change due to CEM findings. Secondary outcome measures included the difference in reoperation/mastectomy rates between the randomisation arms, and estimation of malignant extent by CEM was compared with standard imaging (mammography/tomosynthesis and ultrasound) with histopathological extent as a reference, using Bland-Altman statistics and a concordance analysis. Subgroup analyses were made according to menopausal status, breast density and histopathological type of cancer. This trial was registered with ClinicalTrials.gov, number NCT04437602.Findings: Inclusion was between November 2, 2020, and April 30, 2024. Four hundred and 15 participants completed the trial, 202 in the CEM group, and 213 in the control group. Treatment was changed for 17/202 participants (8·4%) due to CEM findings (95% CI: 5·32 – 13·06). No significant difference between the CEM and control group was seen for mastectomy or reoperation rate. Extent estimation was superior with CEM compared with mammography/tomosynthesis or ultrasound, overall and in the predefined subgroup analysis. Interpretation: The study did not meet its primary endpoint of 10% treatment change but suggests that preoperative CEM might be beneficial for improved extent estimation. Confidence in the method is essential to translate CEM findings into clinically relevant treatment changes.

The authors' abstract, as published at the source. Radiology, 2026 · DOI ↗