Taxanes are a type of chemotherapy and have been a cornerstone of breast cancer therapy for 40 years. So they may be part of your treatment plan, especially if you have HER2-positive breast cancer. About 1 in 5 breast cancers are HER2-positive.
Taxanes, like docetaxel (Taxotere) and paclitaxel (Taxol), treat both early-stage breast cancer and advanced or metastatic breast cancer. About 1 of every 20 women in the United States who are diagnosed for the first time with breast cancer already have metastatic disease.
What Are Taxanes and How Do They Work?
Like most chemotherapy drugs, taxanes stop cancer cells from dividing and growing. Specifically, they're antimicrotubule agents. Microtubules are part of the cell's structure that is used for dividing and replicating itself. Stopping these structures with taxanes results in cell death.
Taxane drugs for early-stage breast cancer can be used to help shrink tumors before surgery. Women who have surgery might continue taking a taxane to keep the cancer from returning.
How Are Taxane Drugs Given?
Researchers are working to find taxanes that can be taken in pill form, which could be more convenient. Now, they are investigating drug combinations of taxanes plus encequidar, a new drug that works in the gastrointestinal tract. In early studies, an oral taxane alone wasn’t effective in slowing down cancer because the body couldn’t absorb enough of the drug. However, when the researchers added encequidar, the gut absorbed the taxane more effectively.
What Can I Expect if I Take Taxanes for Breast Cancer?
Once your doctor decides on taxane therapy, you will be set up on a treatment regimen, visiting the clinic or hospital every certain number of weeks for your treatment. The frequency varies according to the drugs, the dosages, and how the treatment affects you. Docetaxel treatment, for example, is usually given once every 3 weeks and the IV infusion usually takes about an hour each time. On the other hand, paclitaxel is given more frequently, usually every 2 weeks, and it can take up to 2 hours for the infusion. However, some women do get lower-dose paclitaxel once a week.
The drug doses vary according to many factors. These include the type and stage of breast cancer you have, your treatment plan (including which other drugs are added and how often the treatment is given), and even your size.
How long your treatment will last depends on how well the drug works and if you have any reactions. Generally, both docetaxel treatment and paclitaxel treatment last three to six cycles for breast cancer that hasn’t spread (primary breast cancer). Advanced or secondary breast cancers may need longer treatments. But if you have side effects that are serious or make it too hard to tolerate the medication, your doctor may switch you to another treatment.
Do Taxanes Cause Side Effects?
Unfortunately, because chemotherapy drugs attack all cells, including healthy ones, you may have some side effects. Side effects range from minor to quite serious requiring hospitalization. If your side effect is serious, you likely will have to stop this particular treatment. That being said, taxanes are often better tolerated than some other chemotherapy drugs.
Some of the more common taxane side effects are:
- Redness or swelling at the IV site
- Fatigue, which can be extreme
- Muscle aches and pains, called myalgia
- Joint or bone pain
- Nausea and vomiting
- Hair loss
- Skin rashes
- Mouth sores
- Increased risk of contracting an infection
- Pain in the fingers, hands, toes, and feet, called peripheral neuropathy
Serious side effects that should be reported to your doctor right away include:
- Weakness in hands or feet
- Changes in vision, including vision loss
- Unusual bleeding, including nosebleeds, or bruising
- Stomach pain or tenderness
Most of the side effects go away within a few weeks or months after stopping treatment. But some people who had severe neuropathy find that it never goes away completely.
There are also risks associated with combining taxanes with other chemotherapy drugs, like anthracyclines. The combination can cause damage to the heart muscle in some people. This means you may have to go for regular heart tests, such as an electrocardiogram (EKG), so your doctor can monitor your heart function. Blood tests can also tell if there is any damage to your heart tissue.
How Effective Are Taxanes for Breast Cancer Treatment?
For early breast cancer:
Taxanes have been used for many years to treat breast cancer because they can be very effective. A few years ago, researchers reviewed 29 breast cancer treatment studies that included thousands of women. They found that taxanes improved survival rates among women with early breast cancer who would be treated with surgery, and they lowered the rate of returning cancer. The taxanes did, however, increase the risk of some side effects – most commonly low white blood cell counts (neutropenia) and nerve damage that causes weakness and pain or numbness in the hands and feet (neuropathy) – compared with women who had chemotherapy without taxanes.
Given as palliative chemotherapy – that means treatment that extends life but doesn’t cure cancer – taxanes with other chemotherapy drugs can increase chances for survival. Researchers looked at studies evaluating taxanes as treatment for metastatic breast cancer. And they showed that overall, taxanes usually slowed down the cancer’s progress.
Although taxanes are often used for HER-positive breast cancer, they can also be used for women with triple-negative breast cancer. It’s called triple-negative breast cancer, or TNBC, because the cancer cells don’t have estrogen receptors, progesterone receptors, and the HER2 protein.
Taxanes Can Stop Working
As effective as taxanes can be, not all breast cancers respond to the drugs, and you can develop a resistance to them. This can be a particular problem if you have triple-negative breast cancer. Researchers don’t understand why this happens. Sometimes, changing the drug combinations can reverse the resistance, but you may have to change treatment altogether if there is no response.