For some younger women with early-stage breast cancer, a middling Oncotype DX score has left the chemotherapy question open. A new look at data from the TAILORx trial offers doctors more to go on. It was presented on June 3, 2019, at the American Society of Clinical Oncology annual meeting and published that day in The New England Journal of Medicine.
The finding applies to women aged 50 and younger with hormone-receptor-positive, HER2-negative cancer that has not reached the lymph nodes, and a score between 16 and 25. For them, researchers found, adding a measure of clinical risk of recurrence can show who is likely to benefit from chemotherapy after surgery.
What the test measures
Oncotype DX looks at the activity of 21 genes that can influence how likely a cancer is to grow and respond to treatment. The result is a Recurrence Score from 0 to 100. A low score means chemotherapy probably will not outweigh its side effects. A high one, 26 and above, points the other way.
TAILORx enrolled 10,273 women. Those scoring 0 to 10, some 1,626 women or 15.9 percent, got hormonal therapy alone. Another 6,897 women (67.3 percent) scored 11 to 25 and were randomly assigned a treatment, and 1,730 (16.9 percent) scored 26 or higher and received chemotherapy plus hormonal therapy.
Earlier results had already cleared some groups. Findings published in 2015 showed that women scoring 0 to 10 can safely skip chemotherapy. The 2018 results added women over 50 scoring 11 to 25, and women 50 and younger scoring 11 to 15.
Adding clinical risk
The new analysis asked whether tumour size and grade could sharpen the picture. Researchers rated a cancer as low clinical risk if it was under 2 cm and intermediate grade, and high risk otherwise. Of 9,427 women with both pieces of information, 70 percent were low risk and 30 percent were high risk.
Across the whole group, the clinical measure added prognostic information but did not show who would benefit from chemotherapy. Among women 50 and younger with scores of 16 to 25, though, it did. Those at low clinical risk gained little from chemotherapy.
“With this new analysis, it is clear that women ages 50 or younger with a Recurrence Score result between 16 and 20 and at low risk, clinically, do not need chemotherapy,” said lead author Dr. Joseph A. Sparano of the Albert Einstein Cancer Center and Montefiore Health System. He added that combining the score with clinical risk could also identify premenopausal women at higher clinical risk who may benefit from ovarian function suppression and more aggressive anti-estrogen therapy.
Treatment plans still rest on many factors beyond any one test. Women weighing chemotherapy should talk it through with their doctor. Consult your doctor for medical advice.
