In a recent study, researchers find that a 21-gene test performed on tumors could enable most patients with the most common type of early breast cancer to safely forgo chemotherapy.
This means for countless women and their doctors, the days of uncertainty are over.
The researchers from Loyola Medicine examined 21 genes from a patient’s breast cancer biopsy sample to determine how active they are.
The tumor is assigned a “recurrence score” from 0 to 100; the higher the score, the greater the chance the cancer will recur in distant organs and decrease survival.
If patients with higher scores receive chemotherapy, this risk of recurrence will be significantly reduced, enabling more patients to be cured.
Previously, the challenge doctors and patients have faced is what to do if a patient has a mid-range score.
It was uncertain whether the benefit of chemotherapy was great enough to justify the added risks and toxicity.
Previous studies demonstrated that patients with low scores (10 or lower) did not need chemotherapy, while women with high scores (above 25) did require and benefit from chemotherapy.
The current study examined the majority of women who fall in the intermediate range of 11 to 25.
The study enrolled 10,273 women who had the most common type of breast cancer (hormone-receptor positive, HER-2 negative) that had not spread to lymph nodes.
The team examined outcomes of the 69% of patients who had intermediate scores on the 21-gene test.
Patients were randomly assigned to receive chemotherapy followed by hormonal therapy or hormone therapy alone.
The team examined the chemotherapy and non-chemotherapy groups for several outcomes, including being cancer free, having cancer recur locally or to distant sites in the body and overall survival.
They found that for the entire study population with gene test scores between 11 and 25-and especially among women aged 50 to 75, there was no significant difference between the chemotherapy and no chemotherapy groups.
Among women younger than 50, outcomes were similar when gene test scores were 15 or lower.
Among younger women with scores 16 to 25, outcomes were slightly better in the chemotherapy group.
The team suggests that their findings will greatly expand the number of patients who can forgo chemotherapy without compromising their outcomes. More women can avoid the toxic therapy.
The study is published in the New England Journal of Medicine.
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