In the 2025 MOASC Breast Cancer Updates, Evanthia Roussos Torres, MD, delivers a compelling overview of the current challenges and future directions in breast cancer treatment. As a leading researcher and clinician, Dr. Torres emphasizes the critical need for advancements in biomarkers and immunotherapy. These advancements are necessary to improve outcomes for patients with triple-negative breast cancer (TNBC) and hormone receptor-positive subtypes. Below, we dive into her key insights, featuring direct quotes and actionable takeaways from her presentation.
The Urgent Need for Better Biomarkers in Breast Cancer
Dr. Torres opens her discussion by addressing a pressing issue in breast cancer care: the lack of reliable biomarkers. “There’s a real need for better biomarkers for patients with triple-negative breast cancer and other subtypes,” she states. This underscores the importance of identifying which patients will benefit most from existing therapies. Current biomarkers, such as PD-L1 status, are inconsistent. They often change over the course of treatment or vary by biopsy location. For example, she explains, “When you look at PD-L1 status at the beginning of someone’s therapy, it could very well change toward the end.” This variability can mislead treatment decisions, potentially reducing efficacy.
To address this, Dr. Torres advocates for a research-driven approach. “The key to finding these biomarkers is really going to be to study those who are responders and non-responders to the current immunotherapies,” she notes. By analyzing both approved therapies and those in clinical trials, researchers can pinpoint more predictive markers. Ultimately, this can tailor treatments to individual patient needs.
Challenges with PD-L1 and Biomarker Variability
One of the standout challenges Dr. Torres highlights is the inconsistency of PD-L1 as a biomarker. She explains that its reliability depends heavily on where and when a biopsy is taken. “If you’re looking at a patient’s liver met biopsy versus their lung met biopsy, you’re more likely to find PD-L1 positivity in their lung biopsy and a negative result in their liver biopsy,” she says. This discrepancy can dictate treatment choices. It potentially leads to suboptimal outcomes. “That would actually dictate what you choose to move forward with in terms of treatment and very much could mislead you,” Dr. Torres cautions.
This variability underscores the need for more robust tools. Dr. Torres believes the solution lies in continued clinical trial enrollment to collect biospecimens and refine our understanding. “The really important part of this is to continue to enroll patients in clinical trials that are going to allow us to collect biospecimens to do the research,” she emphasizes.
Immunotherapy in Hormone Receptor-Positive Breast Cancer
Shifting focus to hormone receptor-positive breast cancer, Dr. Torres explores the unique challenges and opportunities in this subtype. “Hormone receptor-positive disease is a really big challenge when it comes to treatment with checkpoint inhibition,” she observes. Unlike TNBC, which often responds more readily to immunotherapy, hormone receptor-positive tumors require a deeper understanding of their immune landscape.
Dr. Torres highlights emerging differences within this group: “Patients with luminal B hormone receptor-positive breast cancers actually have more immune-hot tumor microenvironments,” making them prime candidates for immunotherapy. In contrast, luminal A patients need “more of a transformation of their tumor microenvironment to get them to be better responders.” Here, she introduces the potential of CDK4/6 inhibitors as game-changers.
CDK4/6 Inhibitors: A New Frontier in Immune Modulation
A significant portion of Dr. Torres’ update centers on the innovative use of CDK4/6 inhibitors. These are traditionally used as anti-tumor agents. They are now seen as immune modulators. “CDK4/6 inhibitors present us with an opportunity to understand how we can use these drugs as immune modulators,” she says. In luminal A patients, where immune suppression is prevalent, these inhibitors could “transform the tumor microenvironment” to enhance responsiveness to checkpoint inhibitors.
The key, according to Dr. Torres, is sequencing and timing. “This is going to be about understanding how to sequence the drugs and how long to give CDK4/6 prior to coming in with checkpoint inhibitors,” she explains. This approach could unlock new treatment pathways, particularly for hormone receptor-positive patients, where immunotherapy has historically lagged.
Neoadjuvant vs. Adjuvant Immunotherapy: Where’s the Benefit?
Dr. Torres also delves into the debate over neoadjuvant (pre-surgical) versus adjuvant (post-surgical) use of checkpoint inhibitors. She draws from trials like Keynote-522. “It really seems that upfront neoadjuvant treatment with checkpoint inhibitors is where we’re getting the most bang for our buck,” she asserts. She notes that adjuvant benefits appear limited to specific cases, such as patients with residual disease. Trials like Optimize are poised to clarify “who actually needs additional immunotherapy adjuvantly,” she adds.
This distinction is critical for optimizing patient care and minimizing unnecessary exposure to therapies with significant side effects.
Balancing Toxicities in Immunotherapy
A sobering aspect of Dr. Torres’ presentation is her focus on immunotherapy’s toxicities, particularly in curative settings. “It’s a lot to ask of patients to take on the risk of a lifelong autoimmune disease because of a therapy that cured their breast cancer,” she warns. As therapies become more common, toxicities are proving “more abundant than we had anticipated.” This necessitates better prediction and management strategies.
Dr. Torres suggests that measuring initial cytokine levels could help identify patients at risk of severe side effects, allowing clinicians to adjust treatment duration. “If someone has a very reactive immune system, then perhaps we could stop the treatment at an earlier timepoint to prevent subsequent side effects,” she proposes. Until such tools are refined, she urges careful patient selection and close monitoring to catch adverse events early.
The Future of Breast Cancer Research
Looking ahead, Dr. Torres sees immense potential in collaborative research efforts. “The field of research is really tremendous, especially in the community where there are still many opportunities to refer patients for clinical trials,” she says. Breast cancer lags behind other solid tumors in immunotherapy adoption due to its unique immunobiology. However, she remains optimistic. “Once we have a better understanding of that, we will come up with ways to transform our field with these really important therapeutic medications.”
Participation in clinical trials, she stresses, is the linchpin. “It’s really going to be about participation and research so we can better understand it and get to that endpoint,” Dr. Torres concludes.
Conclusion: A Call to Action for 2025
Dr. Evanthia Roussos Torres’ insights at MOASC 2025 paint a picture of a field on the cusp of transformation. From refining biomarkers to leveraging CDK4/6 inhibitors and optimizing immunotherapy, her work highlights the power of research to drive progress. For patients, clinicians, and researchers alike, her message is clear. The future of breast cancer care depends on collective action and innovation. Stay tuned for more updates as these advancements unfold in 2025 and beyond.
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