New Genetic Test Could Spare Millions of Breast Cancer Patients From Chemotherapy
LONDON — In a major breakthrough for personalized medicine, a new international clinical trial suggests that millions of breast cancer patients worldwide can safely bypass the grueling side effects of chemotherapy.
The study reveals that a advanced DNA test can accurately identify individuals who will genuinely benefit from the treatment, versus those who can be successfully treated using hormone therapy alone.
For decades, standard cancer care has relied heavily on chemotherapy to prevent the disease from returning.
However, the trial demonstrates that more than two-thirds of patients with the most common form of breast cancer can completely eliminate the treatment from their recovery plans without compromising their survival rates.
Analyzing Tumor Biology via the Prosigna Test
Led by researchers at University College London (UCL), the sprawling international study evaluated more than 4,000 newly diagnosed breast cancer patients over the age of 40 across the United Kingdom, Sweden, Norway, Australia, New Zealand, and Thailand.
Instead of relying solely on traditional physical indicators—such as tumor size or whether the cancer had reached local lymph nodes—doctors utilized a genomic tool known as the Prosigna test.
How it works: The test examines the molecular activity of 50 specific genes driving cancer growth.
The score: It generates a personalized risk profile calculating the statistical likelihood of the cancer recurring.
Patients who scored in the low-risk bracket—representing roughly 66% of the entire trial group—did not undergo chemotherapy. After five years, the survival rate for the non-chemotherapy group stood at an exceptional 93.7%, nearly identical to the 94.9% survival rate observed among the higher-risk group that did receive the treatment.
Relieving the Physical Burden on Patients
The primary intervention for early-stage breast cancer typically begins with surgery to extract the tumor. Oncologists regularly prescribe subsequent rounds of chemotherapy to destroy any remaining microscopic cells. However, clinicians have long voiced concerns that the systemic treatment offers very little therapeutic value to a vast majority of patients, despite its severe toll on the body.
By substituting chemotherapy with targeted hormone or radiation therapies, eligible patients can avoid devastating short-term and long-term side effects, including:
Severe chronic fatigue and nausea
Complete hair loss
Acute immune system suppression
Permanent fertility complications
Medical experts estimate that within the UK's National Health Service (NHS) alone, over 5,000 patients every year will immediately qualify to skip chemotherapy based on these findings.
A Major Shift Toward Personalized Oncology
The landmark data from the trial is scheduled for official presentation on Saturday at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago—the largest gathering of cancer researchers in the world.
Expert Perspective: "These outcomes represent a monumental milestone toward truly individualized oncology," stated Professor Rob Stein, the trial's chief investigator and a professor of breast oncology at the UCL Cancer Institute. "By allowing tumor biology to dictate clinical decisions, we can spare countless individuals the immense physical and psychological trauma of unnecessary chemotherapy."
Researchers noted that while the data is definitive for women over the age of 40, further trials are still underway to determine if the same genetic testing parameters can be safely applied to patients under 40. Those age-specific results are expected to take several more years to mature.
