A recent large-scale clinical study presented at the ASCO conference in Chicago indicates that patients with early-stage, hormone-sensitive breast cancer can safely avoid chemotherapy by using the Prosigna gene expression test. According to researchers at the Radium Hospital, the study shows that personalized genomic testing can identify which patients derive no significant benefit from cytotoxic treatment, potentially sparing them from months of systemic side effects and long-term complications.
How Does the Prosigna Test Reduce Chemotherapy Use?
The study utilized the Prosigna test to categorize breast cancer patients based on the molecular characteristics of their tumors. Participants were divided into two cohorts: one receiving a combination of chemotherapy and hormone therapy, and another where treatment was guided by the gene test result. According to Hege Ohnstad, an oncologist and specialist at the Radium Hospital, the use of this genomic screening reduced the administration of chemotherapy by 68 percent among the study group. Patients who received a “low score” on the test were able to forgo chemotherapy entirely, relying instead on hormone therapy, without compromising their five-year survival outcomes.
Breast cancer is the most common form of cancer among women in Norway, with approximately 4,500 new cases diagnosed annually, according to the Norwegian Cancer Society (Kreftforeningen).
What Are the Clinical Implications for Patients?
The findings provide critical data for patients previously considered high-risk, including those with cancer spread to the lymph nodes. Previously, clinical guidelines often defaulted to recommending chemotherapy for these cases. However, the study results showed that five-year survival rates were nearly identical between the groups—95 percent for those receiving chemotherapy and 94 percent for those who did not, based on the test results. Ohnstad noted that this data fills a significant gap for premenopausal patients and those with multiple lymph node involvement, offering a clearer pathway for clinical decision-making that avoids unnecessary toxicity.
How Might This Change Future Treatment Standards?
The integration of genomic testing into standard care protocols is expected to shift how oncologists approach treatment planning in Norway and beyond. Hege Ohnstad confirmed that these results will likely influence future national treatment recommendations. By replacing a “one-size-fits-all” approach with molecular profiling, healthcare systems can move toward more precise interventions. This shift not only reduces the physical burden on patients—who avoid 4–6 months of intensive treatment—but also allows medical resources to be reallocated toward therapies that are proven to be more effective for specific tumor profiles.
Frequently Asked Questions
- Who is the Prosigna test for? It is designed for patients with hormone-sensitive, early-stage breast cancer to determine the necessity of chemotherapy.
- Does skipping chemotherapy impact survival? In this study, the five-year survival rates for those who skipped chemotherapy based on a low test score were statistically similar to those who underwent the treatment.
- Is this test available for all breast cancer types? The study specifically focused on hormone-sensitive breast cancer; patients should consult their oncologist regarding the applicability of genomic testing for their specific diagnosis.
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