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By Miriam Mirza

Immunotherapy in cancer treatment was one of the first New Horizons sessions at ECR2024. Ahmed Ba-Ssalamah, Associate Professor at the Medical University of Vienna, initiated the discussion with his presentation on immunotherapy: primers for radiologists. He provided an extensive overview of immunotherapy’s role in cancer treatment and its evaluation using imaging techniques, delving into the mechanisms of immunotherapy and its impact on cancer cells.

This therapy leverages the patient’s immune system to selectively target and eliminate cancer cells. A notable benefit of this approach is the sustained “memory response’’ it creates, Ba-Ssalamah explained. “This is a memory response, i.e., even if you stop the immunotherapy, the antibodies remain and recognize that they are cancer cells and kill them,” he said.

Despite its advantages, assessing immunotherapy morphologically presents challenges. For instance, it requires time for the therapy to manifest its effects, leading to a delayed yet enduring response. Ba-Ssalamah highlighted a paradigm shift in cancer treatment, shifting from traditional methods to leveraging the body’s immune system in selectively combating cancer cells. He underscored the importance of remaining vigilant about new, atypical reaction patterns and the limitations of morphological assessment.

A new approach in the assessment of immunotherapy

Prof. Evis Sala, Professor of Radiology at Università Cattolica del Sacro Cuore and Director at the Advanced Radiodiagnostics Centre of Fondazione Policlinico Universitario Agostino Gemelli IRCCS, then discussed the role of imaging techniques in evaluating immunotherapy responses in cancer patients.

Her talk on assessing immunotherapy response with functional imaging and radiomics, emphasized that conventional assessment criteria often fall short in capturing the unique response patterns of immunotherapy. Thus, functional imaging techniques, such as MRI and PET scans, have gained prominence for their ability to more accurately represent the complex interplay between immunotherapy and tumor cells, especially considering tumor heterogeneity.

Studies indicate that the immune environment differs significantly from conventional tumor parameters, Sala noted. “It turned out that the expression of CD8 cells in the TCG cohort was a stronger independent prognostic factor,” she said, before pointing out the complexity of the tumor microenvironment and coexistence of various tumor environments, which can be visualized through functional imaging and radiomics.

Radiomics, which integrates image features with genetic markers, promises improved predictions of treatment outcomes. This method aids in personalizing treatment plans and enhancing therapy effectiveness. The amalgamation of imaging and biopsy data paves the way for more precise and comprehensive assessments of immunotherapy responses.

‘This integration reinforces the role of radiology in multidisciplinary cancer treatment,’ Sala concluded, emphasizing the necessity of a deep understanding of the immune environment and the integrated application of imaging techniques for accurate immunotherapy response assessment.

The side effects of immunotherapy

Prof. Sandra Baleato-González from the Department of Radiology at Complexo Hospitalario Universitario de Santiago de Compostela, Spain, addressed the side effects of immunotherapy and their imaging.

In her lecture on imaging appearances of immunotherapy adverse effects, she mentioned studies suggesting that 10 to 30 percent of patients experience side effects, the exact causes of which are still not entirely understood. ‘However, these adverse effects are easy to treat or manage and can affect any system and tissue at any time,’ she said.

Particular attention is required for specific side effects like cardiac toxicities (e.g., myocarditis after pembrolizumab) and immune-mediated reactions such as kidney injury or radiation-induced pneumonitis. Understanding and precisely monitoring these side effects is crucial for optimal patient care, she insisted.

In summary, the session demonstrated that immunotherapy represents a significant shift in cancer treatment, offering promising advantages while also introducing new challenges for imaging. As the therapy has the potential to revolutionize cancer treatment, radiologists must be aware of its specific side effects and the need for differentiated assessment. A thorough understanding of immunotherapy and its effects is essential for accurate diagnosis and optimal patient care, the panel concluded.