Reevaluating Radiation Therapy Benefits in Breast Cancer Treatment Using Molecular Risk Assessment

A recent study published in the International Journal of Radiation Oncology Biology* Physics* highlights that relying solely on clinicopathologic factors (CP) for assessing the benefits of radiation therapy in breast cancer, specifically ductal carcinoma in situ (DCIS), can lead to significant misjudgments. The research demonstrates that traditional risk assessments often fail to accurately predict recurrence risk, resulting in over- or undertreatment of patients when compared to advanced molecular-based testing techniques like DCISionRT.

The study, titled "Limitations in the Application of Clinicopathologic Factors Alone in Predicting Radiation Benefit for Women with Low-Risk Ductal Carcinoma in Situ after Breast Conserving Surgery," evaluated 926 women with DCIS treated with breast-conserving surgery (BCS), with or without radiation therapy. The researchers compared recurrence risks and the potential benefits of radiation therapy based on conventional CP risk criteria against results obtained through DCISionRT, a test that incorporates seven biomarkers and four clinical factors into a complex algorithm.

Findings revealed that more than half of the women initially classified as low-risk based on CP assessments were reclassified as high-risk according to their molecular profile, indicating they could significantly benefit from radiation therapy. For instance, 63% of patients considered low-risk by features like the MSKCC nomogram were actually high-risk based on their molecular biology, and thus, more likely to benefit from additional treatment. Similarly, 57% of patients categorized as low-risk with the Van Nuys Prognostic Index (VNPI) and 51% of those based on the RTOG-9804 criteria were shown to have elevated recurrence risks and derived benefit from radiation.

Conversely, a notable portion of patients deemed high-risk by CP criteria were reclassified as low-risk via molecular testing, highlighting the potential for overtreatment if decisions rely solely on traditional factors. The study emphasizes that patients identified as low-risk through both CP and molecular testing exhibited low recurrence rates and did not significantly benefit from radiation therapy.

Experts underscore the importance of integrating molecular profile assessments like DCISionRT in clinical decision-making. Dr. Patrick Borgen from Maimonides Medical Center and other specialists advocate for enhanced use of personalized medicine to tailor treatment plans, aiming to mitigate unnecessary radiation exposure while ensuring high-risk patients receive appropriate care.

The researchers also anticipate that upcoming clinical trials will further validate the utility of molecular testing in optimizing therapy choices. The ultimate goal is to improve patient outcomes by delivering more precise, individualized treatment recommendations based on comprehensive risk assessments that include both traditional and molecular markers.

Source: https://medicalxpress.com/news/2025-07-therapy-benefits-misjudged-clinical-factors.html