Questions to Ask About Breast Cancer Treatment

This page is for people with breast cancer who want to understand their test results before treatment decisions. It walks through the key results, what NCI says about them, and questions to bring to your care team.

Before any treatment question makes sense, three test results have to be on the table. NCI lists them as the core of molecular profiling in breast cancer. They are estrogen receptor (ER) status, progesterone receptor (PR) status, and HER2 receptor status. HER2 stands for human epidermal growth factor receptor 2.

Those three results sort breast cancer into one of three types:

• Hormone receptor positive.
• HER2 positive.
• Triple negative — ER, PR, and HER2 all negative.

NCI states plainly why this matters. ER, PR, and HER2 status help set the prognosis. They also predict response to endocrine (hormone-blocking) therapy and HER2-directed therapy. A drug that works on one type does nothing for another.

There is also a quality-control question worth asking. The American Society of Clinical Oncology and the College of American Pathologists have published consensus guidelines here. Those standardize how these assays are performed, interpreted, and reported. ER and PR are measured by immunohistochemistry, a stain that shows proteins on the cells. HER2 is measured by immunohistochemistry and in situ hybridization, a test that counts copies of the gene. So it is fair to ask which method produced a result, and whether it was borderline.

Beyond the receptors, gene profile tests estimate recurrence risk and help decide about chemotherapy. NCI names three: MammaPrint, Oncotype DX, and the Breast Cancer Index.

MammaPrint was the first gene profile test approved by the FDA. It is a 70-gene signature. It sorts tumors into high-risk and low-risk categories. The MINDACT trial, registered as NCT00433589, set out to test its usefulness. The question was patient benefit for adjuvant chemotherapy decisions, meaning chemotherapy given after surgery to lower the chance of return.

Oncotype DX has the most extensive clinical validation so far. It applies to HER2-negative, hormone receptor-positive breast cancer. It produces a 21-gene recurrence score. That score comes from the expression levels of those genes.

Those score thresholds are worth knowing exactly, because they are decision points rather than descriptions. For node-negative disease:

• Recurrence score of 11 or less: low risk. Chemotherapy is not indicated.
• Score above 11 and up to 25: intermediate risk. NCI calls the decision here complex and personalized. Age at or under 50 versus over 50 feeds into it. So do clinicopathological features and patient preference.
• Score above 25: high risk. Chemotherapy is indicated.

For postmenopausal node-positive disease the cutoff is simpler. A score of 25 or less is low risk, and chemotherapy is not indicated. A score above 25 is high risk, and chemotherapy is indicated.

The Breast Cancer Index combines two profiles. One is the HOXB13 to IL17BR expression ratio, called the H over I ratio. The other is the Molecular Grade Index. It has been both prognostic and predictive in hormone receptor-positive disease.

One older dataset shows why these scores exist. In the NSABP B-14 trial, tissue was available from 668 patients treated with tamoxifen. The 10-year distant recurrence risk was 7% with a low recurrence score. It was 14% with an intermediate score, and 31% with a high score, at P less than .001. Cutoffs have varied between studies, so ask which cutoffs your report uses.

NCI's PDQ summary has sections on follow-up after treatment and on cancer that returns in the same area. We could not open the full text of those sections during our latest check, so this page does not repeat their details. Ask your team what follow-up you will have, why, and which symptoms should prompt a call before your next visit.

For 2026 in the United States, the American Cancer Society projects 321,910 new cases of invasive breast cancer in women. It projects 42,140 deaths, plus 60,730 cases of ductal carcinoma in situ. These annual counts come from Cancer Facts & Figures. NCI says fewer than one in eight women diagnosed with breast cancer will die of the disease.

Men account for 1% of breast cancer cases and breast cancer deaths.

On inherited risk, 5% to 10% of all women with breast cancer may carry a germline pathogenic variant (a harmful inherited gene change) in BRCA1 or BRCA2. Two risk-estimation tools are in common use. One is the Gail model. The other is the IBIS/Tyrer-Cuzick model, version 8. Ask whether a risk estimate has been done for you.

• What are the ER, PR, and HER2 results, and by which method were they measured?
• Was any of those results borderline or equivocal?
• Which type is this — hormone receptor positive, HER2 positive, or triple negative?
• Is a gene profile test being ordered, and which one?
• If Oncotype DX: what is the recurrence score, and which cutoffs apply given node status and menopausal status?
• For an intermediate score, what specifically tips the chemotherapy decision here?
• What will my follow-up consist of, and why?
• Has germline genetic testing been discussed?

For how stage maps onto treatment, see breast cancer treatment by stage and breast cancer stages. This page is a question list drawn from NCI. It does not recommend a treatment.

• NCI PDQ — Breast Cancer Treatment, health professional version
• NCI — Breast Cancer Treatment by Stage
• American Cancer Society — Cancer Facts & Figures