The short answer
Some early breast cancers are tested with a molecular profiling test that estimates the risk of the cancer returning. The TAILORx trial used such a test to identify women who could safely skip chemotherapy. The result changed practice for a large group of patients.
The test is run on tumour tissue and produces a risk estimate, not a diagnosis.
NCI describes TAILORx as showing that a molecular profiling test identifies women with a low risk of recurrence who can be spared chemotherapy.
In the low-risk group, five-year distant relapse-free survival was 99.3% with hormone therapy alone.
In the intermediate group, hormone therapy alone worked as well as hormone therapy plus chemotherapy.
On this page
Choose how you want to read this
The whole article, with every detail and caution.
This page is for people with early breast cancer who have been offered a recurrence score test. It explains what the score measures and what it can and cannot tell you.
The problem the test was built to solve
Chemotherapy after surgery does not help every woman with early breast cancer equally. TAILORx was designed to find out who truly needs it.
That is the gap a recurrence score is meant to fill. It uses a tumor sample to estimate the risk of the cancer coming back, which helps show whether chemotherapy is likely to be needed.
The score is not measuring how bad your cancer is. It is estimating how much a particular treatment would help.
What the TAILORx trial did
The National Cancer Institute describes TAILORx as a study examining whether a molecular profiling test could identify which early-stage breast cancer patients truly need chemotherapy.
Women were grouped by their test result. Treatment was then compared within each group. NCI reports these findings.
Low-risk group. At five years, rates of distant relapse-free survival were 99.3% with hormone therapy alone. NCI's reading is that these patients do not require chemotherapy.
Intermediate-risk group. Adjuvant hormone therapy alone worked as well as hormone therapy and chemotherapy together. After nine years of follow-up, the rates of invasive disease-free survival were 83.3% for hormone therapy alone and 84.3% for hormone therapy and chemotherapy. These figures come from the National Cancer Institute’s “The TAILORx Breast Cancer Trial.”
NCI summarizes the practical consequence. Rather than giving all early-stage breast cancer patients chemotherapy, the trial demonstrated that a molecular profiling test identifies women with a low risk of recurrence who can be spared chemotherapy. This allows treatment to be personalized based on individual risk.
What "spared chemotherapy" does and does not mean
It does not mean spared treatment. In every group described above, hormone therapy was part of the plan. The question the trial answered was about adding chemotherapy on top, not about doing nothing.
It also does not mean the score decides on its own. Your cancer's size, its other features, your age and your own view of the trade-offs all belong in the conversation. A test result is evidence brought into a decision — it is not the decision.
Living with a number that is a probability
Recurrence scores describe likelihood across groups of people. They cannot tell any individual what will happen to them, and it is worth being honest with yourself about that when you receive one.
A low score does not promise safety and a higher one does not promise trouble. What a score does is let you and your oncologist reason about a real choice with better information than a coin toss.
Some people find that clarifying. Others find the probabilistic framing hard to sit with, particularly when they had hoped for a definite answer. Both reactions are normal. Tell your team which one you are having. It can change how they talk you through the options.
Questions that make the conversation better
The most useful thing you can do with a score is turn it into a comparison. Ask your oncologist to walk you through what they would recommend with the result, and what they would have recommended without it. If the answer is the same either way, that is useful to know. If it is different, you learn exactly what work the test is doing.
Then ask about the trade-offs on both sides — what chemotherapy would involve for you, and what the plan without it looks like, including follow-up.
The point of a recurrence score is to make a hard decision more informed. That only happens if the information actually reaches you in a form you can use.

Common questions
Does a low score mean my cancer is not serious?
It means the test estimates a low risk of the cancer returning at a distance, which is what allowed the low-risk group in TAILORx to be treated with hormone therapy alone. It is a statement about likely benefit from chemotherapy, not a statement that treatment is unnecessary.
What did TAILORx actually show for the middle group?
NCI reports that for the intermediate-risk group, adjuvant hormone therapy alone worked as well as hormone therapy and chemotherapy together, with invasive disease-free survival at nine years of 83.3% versus 84.3%.
Does this apply to every breast cancer?
No. TAILORx studied early-stage breast cancer, and testing of this kind is used in specific situations. Your oncologist can tell you whether it is relevant to your particular cancer.
Can I refuse chemotherapy because of my score?
Treatment decisions are always yours to make with your team, and a score is one part of that conversation alongside your cancer's other features and your own priorities. This page cannot tell you what to choose.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Your next step
Turn this topic into questions for your next appointment.
Talk with a trained specialist or navigator
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Sources last checked: 2026-10-02 what this meansLast updated: 2026-08-11Next planned review: 2027-08-11
Review details and limits
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status — Source checked. This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Words to know
Tap any term to see what it means.
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.
