Chemotherapy drugs are a specific class of medications called cytotoxic agents. They’re designed to kill cancer cells.

Cancer cells grow faster than regular cells. These drugs disrupt the growth of fast-growing cells and leave slower-growing cells generally unharmed.

Some chemotherapy (“chemo”) drugs damage the genetic material of the cells. Others interfere with the way the cells divide. However, some also affect other fast-growing cells in the body, such as hair, blood cells, and cells in the stomach lining and mouth. This accounts for some of the more common side effects.

Not all people who receive a diagnosis of breast cancer will need chemotherapy. Cancer can often be effectively treated with local therapies like surgery and radiation, without systemic treatment.

If you’ve received a diagnosis of larger tumors where the cells have spread to nearby lymph nodes, you may need a few rounds of chemo. In these cases, chemo is used as adjuvant therapy, or to prevent cancer from returning after the tumor has been removed.

If you’ve received a diagnosis of a stage 3 cancer and larger tumors, you may go straight to systemic treatment before getting surgery. This is called neoadjuvant treatment.

While the idea of chemotherapy may be intimidating, there have been significant improvements in how side effects are managed. Undergoing chemotherapy is much more tolerable than it used to be.

In cases of early stage cancer, an oncologist can make an informed decision about which drugs are best to use. Your age, the stage of the cancer, and any other health problems will all be taken into consideration before deciding on a chemo regimen.

These drugs are usually injected into a vein, either at your doctor’s office or at a hospital. Locations that provide chemotherapy injections are often called infusion centers.

You may need a port implanted if you have weak veins or are being given a certain type of drug. A port is a device that’s surgically placed in your chest that allows for easy needle access. The port can be removed when therapy is finished.

Typically, a person is given several drugs, often called a regimen. Regimens are designed to attack the cancer at different stages of growth and in different ways. Your chemo drugs will be given on a regular schedule in doses called rounds.

According to the American Cancer Society, the most common drugs and regimens used for breast cancer today are:

Regimen name (drug initials)List of drugs in treatment
CAF (or FAC)cyclophosphamide (Cytoxan), doxorubicin (Adriamycin), and 5-FU
TACdocetaxel (Taxotere), doxorubicin (Adriamycin), and cyclophosphamide (Cytoxan)
AC-Tdoxorubicin (Adriamycin) and cyclophosphamide (Cytoxan) followed by paclitaxel (Taxol) or docetaxel (Taxotere)
FEC-T5-FU, epirubicin (Ellence), and cyclophosphamide (Cytoxan) followed by docetaxel (Taxotere) or paclitaxel (Taxol)
TCdocetaxel (Taxotere) and cyclophosphamide (Cytoxan)
TCHdocetaxel (Taxotere), carboplatin, and trastuzumab (Herceptin) for HER2/neu-positive tumors

While chemotherapy treatments have greatly improved over time, there are often still noticeable side effects of treatment.

Hair loss

Not all chemo drugs cause hair loss, but most of those mentioned above for early stage cancer will have that side effect.

If you’re self-conscious of your hair loss, you can incorporate wigs, hats, and scarves into your wardrobe. This side effect is generally temporary, however. Your hair will likely begin to grow back once you stop chemo treatment.


Some may be concerned about nausea as a chemo side effect. But this side effect is becoming less common as treatment methods progress.

You’ll be given steroids and powerful anti-nausea medications along with your infusion. You’ll also be given some medication to take at home. Many people find that they don’t have any nausea at all and can even gain weight on chemo.


Constipation can be a side effect of chemo drugs. Be sure to incorporate fiber into your diet, and take stool softeners if you need to.

Mouth sores

Mouth sores are an occasional side effect. If they appear, you can ask your oncologist for a prescription for “magic mouthwash,” which has a numbing agent. Also, it’s possible your sense of taste will change with some chemo drugs.


The most common and persistent side effect of chemo is tiredness.

Chemotherapy affects your blood and bone marrow. Often a person undergoing chemo will become anemic, which causes fatigue. The effect on the blood also leaves you potentially susceptible to infection. It’s important to rest as much as possible.

Menstrual and fertility changes

If you have a menstrual cycle, you may find that it changes under chemotherapy. Some people start menopause after completing chemotherapy. This becomes more common the closer you are to menopause, which typically starts around the age of 51.

Periods can return after treatment is completed, but this often depends on your age and what kind of chemotherapy drugs were used. Typically, the younger you are, the greater the chance is that your period will return and you’ll produce fertile eggs.

Talk with your doctor if you hope to get pregnant after chemotherapy. They can help design a treatment plan that least affects your fertility.


While most of these side effects go away when you complete your chemo regimen, a few effects may remain.

One of these is neuropathy. It occurs when the nerves of the hands and feet are damaged. People with this side effect feel tingling, stabbing sensations, and numbness in these areas.


Osteoporosis is another potential lasting side effect. People who’ve undergone chemo should have regular bone density checks.

Increased risk for leukemia

Although rare, receiving chemotherapy can put you at higher risk for developing leukemia down the line. If this is the case, it usually appears within 10 years of receiving chemotherapy.

For most people, the benefits of receiving chemotherapy to help treat breast cancer outweigh the slight risk for developing leukemia.

Cognitive difficulties

Cognitive difficulties that occur with treatment can cause short-term memory loss and problems concentrating. This is known as “chemo brain.”

Usually, this symptom improves shortly after therapy concludes. However, sometimes it can persist for years.

Heart weakening

In some cases, chemo can leave you with a weaker heart.

Rarely, an allergic reaction to chemotherapy drugs can happen as well. Your medical team will monitor you closely for any signs that this may occur.

The prospect of undergoing chemotherapy can be scary, but most people are surprised to find that it’s quite manageable. Many can even keep up with their careers and other regular activities at a reduced level.

While undergoing chemo, it’s important to eat a nutritious diet, rest as much as possible, and take care of your mental health.

Finding out that you must undergo chemo can be difficult, but remember that it won’t last forever.

It may help to talk to others who have gone through the same thing. Explore support groups online, and check out our list of best breast cancer blogs of the year.