An illustration · invented records · the research is real
The research question and its scope
This question guided the search from the start. The family question that started it is in the question log; the office’s clarification that named the test is here.
The question
For a postmenopausal woman with early-stage, hormone-receptor-positive, HER2-negative, node-negative invasive breast cancer, what can the 21-gene recurrence score test tell clinicians about whether adding chemotherapy to endocrine therapy is likely to help, and what are the limits of that evidence?
Who it is for
Mom and her adult children, none with medical training. It is meant to help them understand what the test is for and prepare their questions for September 15. Whether it would help with Mom’s care is a conversation for her and her clinicians.
What “matches Mom’s situation” means here
Taken from the records in this folder, not from anything else:
| Feature | Mom’s record | Where it is written |
|---|---|---|
| Menopausal status | Postmenopausal | Imaging report |
| Tumor | Invasive carcinoma of no special type, grade 2, about 1.8 cm | Biopsy report |
| Receptors | ER positive, PR positive, HER2 negative | Addendum |
| Lymph nodes | Normal on ultrasound; final status unknown until surgery | Imaging report · Visit summary |
| Surgery | Not yet done | Visit summary |
So the evidence we looked for is about people with hormone-receptor-positive, HER2-negative early breast cancer deciding about chemotherapy after surgery. Evidence about people with one to three positive lymph nodes is included as a boundary, because Mom’s final node status is not known yet. Evidence about premenopausal women is mentioned only where it marks a limit of what applies to postmenopausal women.
Outside this research question
- HER2-positive and triple-negative breast cancer (different tests, different decisions).
- Ductal carcinoma in situ on its own.
- Four or more positive lymph nodes.
- Chemotherapy given before surgery.
- Cost, insurance coverage, and whether a plan pays for the test.
- Other genomic tests (70-gene, EndoPredict, Prosigna, and others), beyond noting that they exist and that this test is not the only one.
- Anything that would amount to a recommendation for Mom.
Where we looked and how far back
PubMed, OpenAlex, and ClinicalTrials.gov, with open-access full text where it exists, from 2004 onward (the year the test was first validated in print). Details, counts, and what was dropped: How we researched this.
What the answer looks like
The summary sorts what we found into three tiers: what is established about the test, what is still being studied, and which questions remain open. Every claim that carries weight links to a source note with a real identifier, a quoted passage where full text was available, and a note on how the quote was checked.