The short answer
AC-T is the breast cancer combination NCI lists as doxorubicin hydrochloride, cyclophosphamide, and paclitaxel. It runs in two phases: AC first, then paclitaxel. The heart is watched because of doxorubicin, and numbness in the hands and feet is watched because of paclitaxel.
NCI lists AC-T as doxorubicin hydrochloride (Adriamycin), cyclophosphamide, and paclitaxel (Taxol), and names breast cancer as its use.
The AC phase comes first; the paclitaxel phase follows it.
ACS describes AC every 2 weeks followed by paclitaxel as an example of dose-dense chemotherapy; a 3-week interval is the other schedule.
ACS puts adjuvant and neoadjuvant chemotherapy at 3 to 6 months in total, depending on the medicines used.
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The full explanation.
The short answer
AC-T is a chemotherapy combination for breast cancer. The letters stand for its drugs. Doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan) come first, as "AC." Paclitaxel (Taxol), the "T," follows later. Doctors combine different drugs because they attack cancer in different ways. This usually works better than one drug alone.
How the two parts fit together
AC-T comes in two phases, one after the other. First you get doxorubicin and cyclophosphamide together, often called "AC," for several cycles. After that phase ends, you move to paclitaxel, the "T," for more cycles. Some plans give doses every two weeks, with medicine support to keep blood counts up. Others use a three-week schedule. Ask your oncologist which schedule applies to you. It shapes what side effects to expect and when.
How it is given
All three drugs go into a vein. This is usually through an IV line or a port placed under the skin. Treatment comes in cycles. Each cycle has a dose, then a rest period that lets your body recover. Chemotherapy given after surgery is called adjuvant treatment. Chemotherapy given before surgery is called neoadjuvant treatment. Both commonly run three to six months in total. Your exact plan depends on your cancer's stage and features.
Common side effects
Doxorubicin and cyclophosphamide commonly cause hair loss, nausea, and vomiting. Fatigue is common too. Blood counts often drop for a while, which raises infection risk. Paclitaxel, given in the second phase, commonly causes numbness or tingling in the hands or feet. Doctors call this neuropathy. It can come with fatigue and joint or muscle aches. All three drugs can affect appetite. They can also raise bleeding or bruising risk when platelets drop.
Two side effects that need special watching
Doxorubicin can cause permanent heart damage, called cardiomyopathy. This risk grows with higher total doses. Your team may check your heart with tests before you start. They may check again during treatment. Report new shortness of breath right away. Also report leg swelling or chest discomfort. Do not wait for your next visit.
Paclitaxel's numbness and tingling, called neuropathy, can grow more noticeable as treatment continues. In some people, it does not fully go away after treatment ends. Tell your team as soon as it starts. They can track it and adjust your dose if needed. Do not wait until it makes daily tasks hard, like buttoning a shirt or walking safely.
Which symptoms cannot wait
CDC says to call your doctor immediately if your temperature is 100.4°F (38°C) or higher — at night and at weekends too. When AC-T has thinned your infection-fighting cells, an infection can turn serious within hours, and CDC treats fever during cancer treatment as a medical emergency. If you do end up at an emergency room, tell the person checking you in that you are having chemotherapy. Chest pain means 911 or an emergency department, as does breathlessness that comes on suddenly or is there at rest — doxorubicin can weaken the heart muscle. Call your care team the same day for breathlessness that has built gradually on exertion, or for fast swelling.
What to expect day to day
Most people get AC-T as an outpatient. You go home the same day as each dose. Fatigue and nausea often peak in the days right after a dose. They usually improve before the next one. Anti-nausea medicine prescribed alongside chemotherapy can help a great deal. Speak up if it is not working well enough. Hair loss during the AC phase is common. It often begins two to three weeks after the first dose.
How this fits with the rest of your treatment
AC-T can be given before surgery to shrink a tumor. It can also be given after surgery to lower the chance the cancer returns. Which one fits you depends on your specific situation. Your team will also consider hormone therapy or targeted therapy against HER2. These work through different mechanisms. They are often combined with, or given after, chemotherapy.
What to ask your care team
- Will I get AC and T on a two-week or three-week schedule, and how many cycles of each?
- How will you monitor my heart during the AC phase?
- What should I do if I notice numbness or tingling during the paclitaxel phase?
- What temperature or symptoms should make me call you the same day?
Sources
Words to know
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Common questions
What three drugs make up AC-T?
Doxorubicin hydrochloride (Adriamycin) and cyclophosphamide, given together as the AC phase, then paclitaxel (Taxol) as the T phase.
How long does AC-T take?
ACS says adjuvant and neoadjuvant chemotherapy usually runs 3 to 6 months in total, depending on the medicines used. Your number of cycles and whether you are on a 2-week or 3-week schedule set the exact length.
What is dose-dense AC-T?
ACS uses AC every 2 weeks followed by paclitaxel as its example of dose-dense chemotherapy: the same cycles given closer together, which ACS says can lower the chance of recurrence for some women but needs closer blood count monitoring.
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Sources last checked: 2026-08-13 what this meansLast updated: 2026-08-19Next planned review: 2027-01-20
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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. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Editorial review complete — This page completed Cancer Explained's editorial checks (sources, safety, plain language, duplication). It has not been reviewed by a physician or other healthcare professional.
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.
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