For women whose tumors received a low Oncotype DX score (1-10) or a high one (26 to 100), decisions on post-surgical chemotherapy have been clear. Low scores mean women receive hormonal therapy only to keep cancer from spreading, while patients with a high score get hormonal therapy plus chemotherapy.
But prior to the new trial, “there was uncertainty about the best treatment for women with a mid-range score of 11-25,” Sparano explained. “The trial was designed to address this question, and provides a very definitive answer.”
The new study focused on 6,711 women with early stage, hormone receptor-positive, HER2-negative, axillary node-negative breast cancers. All had received a mid-range Oncotype DX score.
The patients then went on to receive either hormonal therapy alone or the combo of hormonal therapy plus chemotherapy.
The result: After an average follow-up of 7.5 years, the researchers saw no added benefit in this group to adding chemotherapy to the treatment mix. There was no benefit in terms of overall survival, disease-free survival, or cancer spread beyond the breast.
There was some benefit from the chemotherapy for a small subgroup — women with a score of 16 to 25 who were age 50 or younger, Sparano’s team said.
In a separate analysis, hormonal therapy alone did seem very effective in deterring the spread of cancer for women with an Oncotype score of 10 or below. And for those with scores of 26 or above, 13 percent went on to develop metastatic cancer despite receiving both hormonal treatment and chemotherapy, the team said.
Based on all this, Sparano’s team concluded that chemotherapy is now unwarranted in women over 50 with this type of breast cancer who have an Oncotype score under 26. That comprises about 85 percent of women with breast cancer in this age group, the researchers noted.
For women 50 or younger, chemotherapy is unwarranted for those with an Oncotype score under 16 — about 40 percent of breast cancers in this age group, the researchers said.
That’s great news, since the short-term side-effects of chemotherapy can include everything from nausea, hair loss, fatigue and infection, to numbness in hands and feet, and other symptoms. Longer-term effects of chemotherapy include infertility and heart failure.