Early-stage breast cancer: Does it make sense to have chemotherapy?
Women who have had surgery to remove early-stage breast cancer are often worried that the cancer will return. Chemotherapy can reduce the likelihood of a recurrence. But this treatment isn’t always a good idea because the disadvantages sometimes outweigh the advantages.
If breast cancer is discovered at an early stage, surgery can often remove all of the tumor. Many women have radiotherapy too. But some cancer cells might be left in the body. These can start growing again after a while, even years later. The medical term for this is “recurrence” or “relapse.”
The tumor may grow back in the breast or in nearby tissue (a local recurrence) or spread to a different part of the body (distant recurrence). If breast cancer comes back, the chances of a full recovery are usually much lower.
When deciding about treatment, it’s important to know how high the risk of recurrence is: The higher a woman's risk of recurrence, the more likely she is to benefit from chemotherapy. Because of this, doctors routinely determine the women’s risk of recurrence after breast cancer surgery.
How is the risk of recurrence determined?
Doctors determine a woman’s risk of recurrence after breast cancer surgery based on various clinical criteria:
- Involvement of lymph nodes: Has the cancer spread to lymph nodes? If so, how many lymph nodes?
- Hormone sensitivity: Does the tumor have receptors for hormones such as estrogen and progesterone (hormone-receptor-positive breast cancer)?
- Grade of differentiation: How different are the tumor cells to normal breast cells?
- Size of the tumor: How big is the tumor?
- Speed of tumor growth: How fast did the tumor cells grow (Ki67 index)?
- Growth factors: Does the tumor have a lot of receptors for certain growth factors (HER2/neu)?
- Age: How old is the woman? Has she already reached menopause?
A lot of these clinical criteria are determined based on a tissue sample taken from the tumor during surgery.
Doctors use special tables to help them estimate the risk of recurrence.
The risk of recurrence is a measure of how likely it is that a woman will get cancer again. It’s not possible to predict whether the cancer will return in a particular woman.
In some women it also makes sense to do an “oncotype DX” test. This involves looking at other biological characteristics of the tumor in a laboratory.
What does a low risk of recurrence mean?
Women who have a low risk of recurrence are generally advised not to have chemotherapy. Although chemotherapy slightly reduces the risk of their cancer coming back, doctors consider the side effects to outweigh this potential advantage.
Some experts call it a “low risk of recurrence” if the cancer comes back in less than 5 out of 100 women with that risk within 10 years. Others consider the threshold to be 10 out of 100 women.
What does a high risk of recurrence mean?
Women who have a high risk of recurrence are generally advised to have chemotherapy. This treatment will greatly reduce the likelihood of their cancer returning. Doctors consider the advantages of chemotherapy to outweigh the disadvantages here.
Many doctors recommend chemotherapy if more than 15 out of 100 women with that risk of recurrence get breast cancer again within 10 years. Others consider the threshold to be 20 ouf of 100 women.
What does an intermediate risk of recurrence mean?
Some women don't have a clearly low or clearly high risk of recurrence. Their risk of getting breast cancer again lies somewhere in between. This is known as an intermediate risk of recurrence.
Women who have an intermediate risk of recurrence often find it particularly hard to decide whether or not to have chemotherapy. There are two reasons for this:
- The pros and cons of chemotherapy can almost balance each other out: Would you prefer to avoid the distress and potential side effects associated with chemotherapy? Or do you find it more important to try to reduce the risk of recurrence?
- Even without chemotherapy, the cancer will only come back in quite a small number of women. All of the other women will go through this distressing treatment for no reason.
What can you expect from chemotherapy?
Chemotherapy reduces the risk of recurrence (the likelihood of getting breast cancer again) by about one third on average. What this means for a woman will depend on how high her risk of recurrence is. Consider the following three examples:
Risk of recurrence after chemotherapy
What are the disadvantages of chemotherapy?
Chemotherapy can be hard to deal with psychologically and may reduce your quality of life. It can also have various side effects.
The side effects of chemotherapy will depend on the exact drugs used and how many cycles of treatment the chemotherapy involves. They can generally be divided into three categories:
- Side effects that are common but not life-threatening: A lot of women experience the typical side effects of chemotherapy such as nausea, hair loss and exhaustion. These side effects last longer in some people than in others.
- Side effects that can be life-threatening: It is estimated that about 10 out of 100 women have to go to hospital or the emergency room within a year due to their chemotherapy. This is often because the chemotherapy weakens their immune system so much that their body can’t even fight off infections that would usually be harmless. If the typical symptoms are particularly severe, they can also become life-threatening (for instance, extreme nausea or vomiting).
- Side effects and consequences of chemotherapy that can affect your life after the treatment has ended: There's hardly any research on how common these kinds of side effects are. Serious complications following chemotherapy are rare, but can be particularly severe. Nerve damage is one example. Women who experience this side effect might, for instance, not feel anything in their fingers or toes for a long time. Chemotherapy may damage the heart too. It is estimated that this happens in about 3 out of 100 women. Chemotherapy also increases the risk of leukemia developing years later. But this happens in fewer than 1 out of 100 women.
Women who would still like to have children should be aware that chemotherapy can reduce your chances of getting pregnant. It can make your menstrual periods stop or your menopause might start earlier. It’s a good idea for women who would still like to have children to consult their doctor before having chemotherapy. There are various things you can do before chemotherapy to increase your chances of being able to get pregnant afterwards.
Weighing the pros and cons of chemotherapy
The main question is: Do you consider chemotherapy to have more potential advantages or more potential disadvantages? The answer to this question will be different for different women – and different doctors.
The answer will mostly depend on how much the chemotherapy is expected to help: The higher the risk of recurrence, the greater the potential benefit of chemotherapy. If the risk of recurrence is low, the side effects of chemotherapy are more likely to outweigh the potential benefits. But the woman's overall physical condition and life expectancy also play an important role in the decision. For instance, if a woman already has a heart problem or kidney damage, chemotherapy could be too much for her body to handle.
Various individual aspects play a role, too. These include how worried the woman is about the cancer coming back and how distressing that is for her, or how well she thinks she would be able to cope with the side effects of chemotherapy. Her current life circumstances may affect the decision as well. But there’s no right or wrong here.
Although it’s often hard to make a decision, nobody has to do so alone. Doctors are obliged to give every woman the support she needs. It can also be helpful to go to a different doctor and get a second opinion.
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Decision aid for biomarker tests in breast cancer: Addendum to Commission D14-01; Commission P17-03. November 15, 2017. (IQWiG reports; Volume 558).
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