Understanding the Safety Profile of CEM

Researchers recently presented findings from the TOCEM trial, which evaluated contrast reactions in CEM over three years of annual screening. The prospective study monitored 1,651 women with a personal history of breast cancer who received a total of 3,873 injections of iopamidol. As contrast-enhanced mammography (CEM) becomes a more frequent supplemental screening tool, understanding its safety profile is essential for radiologists and oncologists alike.

Findings on Contrast Reactions in CEM

The results showed that only 38 out of 3,873 injections resulted in a reaction, equating to a low overall rate of 0.98%. Specifically, allergic-like reactions were the most common, appearing in 0.65% of cases. Most of these (80%) were cutaneous, such as hives or rashes. Additionally, the study noted that patients receiving contrast for the first time had a significantly higher risk (1.96%) compared to those with prior uneventful exposure (0.42%).

Furthermore, the study identified five delayed allergic-like reactions. These symptoms appeared between one and seven days after the initial administration. Only two reactions were severe enough to prevent the completion of imaging. However, most reactions were mild, although 60% of those with allergic-like symptoms required medication for management. Consequently, CEM remains a safe supplemental screening tool for high-risk populations. Clinicians should still remain vigilant for delayed cutaneous symptoms even after the patient leaves the clinic.

Frequently Asked Questions

What is the overall incidence of contrast reactions in CEM?

Based on the TOCEM trial data, the overall incidence of contrast reactions is low, at approximately 0.98% across thousands of injections.

Are patients new to contrast agents at higher risk?

Yes. The study found that contrast-naïve patients had a significantly higher reaction rate (1.96%) compared to those with prior uneventful exposure (0.42%).

What types of delayed reactions should clinicians watch for?

Delayed reactions are primarily cutaneous, such as hives or rashes, and can occur between one and seven days after the procedure.

Disclaimer: This content is for informational and educational purposes only and does not constitute medical advice or a professional relationship. Healthcare providers should perform their own independent assessment. Refer to the latest local and national guidelines for clinical practice.

References

Gu L et al. Prevalence of Acute and Delayed Contrast Reactions With Multiple Exposures to Contrast-Enhanced Mammography-Experience From the TOCEM Trial. J Breast Imaging. 2026 Feb 09. doi: undefined. PMID: 41661649.

Zanardo M, et al. Adverse events in contrast-enhanced mammography: a systematic review and meta-analysis. European Radiology. 2023;33(10):6741-6751.

American College of Radiology. ACR Manual on Contrast Media. 2023. URL: https://www.acr.org/Clinical-Resources/Contrast-Manual