BCRF’s guide to the most common side effects of breast cancer, plus expert advice for finding relief
Every person’s experience with breast cancer is unique, but whatever your diagnosis, the disease will almost certainly affect more than your breasts. Understanding the side effects of breast cancer treatment is the first step toward getting relief.
“Years ago, in the initial stages of researching breast cancer, we were primarily focusing on the efficacy of treatment. As long as something worked, that was the most important thing,” says Breast Cancer Research Foundation (BCRF) Scientific Advisory Board Member Dr. Dawn Hershman. “But over time, we’ve developed newer treatments. Now we can focus more on how to measure the side effects of treatment and determine whether the benefits are worth the risks.”
Whether your symptoms are driven by the treatments themselves or the resulting hormonal shifts, you are not alone, and there are proven strategies to help you feel more comfortable.
Key takeaways
- Breast cancer and its treatments affect the entire body, from cognitive function and mood to cardiovascular and sexual health, largely due to hormonal shifts, chemotherapy, and radiation.
- Lifestyle adjustments (like diet and exercise), targeted therapies (such as cognitive behavioral therapy or cold capping), and medication changes can significantly relieve symptoms.
- Managing symptoms is a highly personalized process that requires constant balancing. This is especially vital when navigating the long-term side effects of breast cancer treatment or sustaining quality of life during metastatic breast cancer treatment.
- Maintain open, ongoing communication with your care team so they can adjust your regimen and help you feel better while staying on track.
What are the common side effects of breast cancer treatment?
Because about 80% of diagnoses are hormone receptor-positive, many treatments involve blocking or reducing estrogen. This profound hormonal shift, combined with chemotherapy and radiation therapy, can cause a wide range of physical and emotional changes.
If you’re grappling with unfamiliar physical, cognitive, or emotional struggles, you’re not alone. It’s well worth talking with your doctor about personalized treatment and/or lifestyle changes that can help you feel more comfortable. Because forewarned is forearmed, here are the most common ways breast cancer can affect your body and mind.
Here are the most common ways treatment can affect your body and mind, along with expert advice for finding relief:
Energy Loss and Fatigue
Declining estrogen levels can disrupt neurotransmitters that affect your sleep patterns, mood (more on that later), and temperature regulation. In addition, cancer itself, as well as radiation and chemotherapy treatments, may cause inflammation, leading your body to overproduce cytokines, the chemical messengers of the immune system that can send signals to the central nervous system that result in fatigue, among other symptoms. Cancer and its treatments may also cause anemia, a shortage of the red blood cells that carry energizing oxygen to our tissues and organs. If your weariness is accompanied by symptoms like dizziness, dehydration, heart palpitations, headaches, and/or cold hands or feet, follow up with your doctor.
Finally, let’s state the obvious: The stress of dealing with a cancer diagnosis and making decisions about treatment, along with keeping up your normal life stuff, can be exhausting. Not to mention, you’ve probably strayed from your regular routine, so you may not be getting as much exercise, nutritious food, or quality sleep as you need, all of which can seriously zap your energy.
How to get relief
- Make sure your diet is iron-rich (including fruits and vegetables, beans, and leafy greens), especially if you’re anemic—but talk to your doctor before you take any iron supplements.
- Move regularly, even if a short, gentle walk or yoga session is all you can handle.
- Practice good sleep hygiene: Keep your bedroom cool and dark, avoid afternoon caffeine breaks or screens at bedtime. If you’re really struggling with insomnia, Dr. Hershman suggests considering cognitive behavioral therapy for insomnia (CBT-I).
Cognitive Changes
Perhaps lately you’ve noticed little lapses in memory or concentration. You forget to check items off your grocery list. You accidentally throw away the grocery list. While some of these lapses may naturally occur with age, breast cancer treatments may make the story even more complicated. Research has indicated that some level of cognitive impairment is common among those who have or have had breast cancer, affecting as many as one in three individuals, according to a 2022 review of studies published in Nature Scientific Reports. Researchers theorize this is caused by a combination of declining estrogen, chronic stress, and the physiological changes brought on by treatments.
How to get relief
For many patients, chemo brain (also known as chemotherapy-related cognitive impairment) and other cognitive difficulties will resolve after treatment. That said, the effects can persist for years afterward, so make a follow-up appointment with your doctor if symptoms persist.
- Maintain healthy lifestyle habits: Sleep, movement, and nutritious food are important factors in shoring up cognitive powers.
- Practices like meditation have demonstrably improved both the outlook and cognitive capabilities of breast cancer patients with “chemo brain.”
- Become a unitasker. Research has shown that when we try to do more than one thing at a time, we’re slower and more prone to making errors.
- Track the times and situations when you typically feel sharpest, and save your more thought-intensive tasks for that time of the day.
Mood Changes
“Changing people’s hormonal environment can trigger depression on top of some of the other acute stressors of going through a breast cancer diagnosis,” Dr. Hershman says, adding that both tamoxifen and aromatase inhibitors can trigger mood changes. When we are low on estrogen, we are also low on feel-good neurotransmitters like serotonin. So, in addition to acute stressors, changing your hormonal environment can trigger depression. following a breast cancer diagnosis and treatment.
And if your treatment is over but your spirits are still lagging, that’s normal too. “A lot of times people are just focused on getting through it, and they think that when they’re done, they’re going to feel better,” Dr. Hershman says. “But in the aftermath, you may be dealing with nagging thoughts like: What if it comes back? What if I have to go through this again? And easing back into your regular routine can feel overwhelming.”
How to get relief
- Whether or not you opt for medication, therapy (such as psychodynamic or cognitive behavioral therapy) can also be helpful.
- If you’re able to get back into an exercise routine, the American College of Sports Medicine offers research-based regimens. Studies show that three weekly 30- to 60-minute sessions of moderate-to-vigorous aerobic activity can help alleviate depression.
- Antidepressants can help. Certain antidepressants can not only improve mood but also reduce other side effects like hot flashes or joint pain.
Hair Loss
On top of all the other changes and challenges that come with cancer, the prospect of losing your hair can be particularly distressing. Most cancer-related hair loss is due to chemotherapy drugs, which target rapidly growing cells, including those in your hair follicles. Some medications, Dr. Hershman says, have more significant effects on the scalp, including more hair loss and slower regrowth. Longer-term hair loss may also be related to simultaneous hormonal changes.
A less widely discussed concern is hair loss in areas other than your head. Your eyelashes may grow thin or fall out altogether, leaving your eyes vulnerable to dryness and irritation. You may also gain a new appreciation for your nose hairs. And once the hair on your head grows back, your formerly straight-haired self may be sporting so-called “chemo curls” as a result of the drugs’ changes to the hair follicle, although your new “do” most likely won’t be permanent.
How to get relief
- You may have heard of cold capping, which involves wearing a special cooling cap before, during, and after chemotherapy treatments. “Even if it doesn’t preserve all the hair, there’s some evidence that it can help hair grow back faster afterward,” Dr. Hershman says.
- For hormone-related hair loss, the topical over-the-counter drug may help. Always consult your care team before adding something to your routine.
- There’s also some evidence that after your treatment is over, some supplements may help encourage regrowth of your hair and nails (talk to your doctor before starting any supplements). Cooling gloves and socks may also help prevent nail damage.
Skin Irritation and Dryness
Radiation therapy can damage healthy skin cells, leaving your skin red and irritated (similar to a sunburn), dry, and/or itchy. Like other symptoms, this is typically temporary, healing a month or so after your treatment is over.
It’s possible, however, to experience late-onset irritation, which may appear weeks or months after treatment; if you notice any changes, be sure to loop in your radiation-therapy team.
How to get relief
- Use mild, unscented soap and lotion.
- Avoid antibacterial soaps, which can be drying; moisturizers with lanolin, which can cause an allergic reaction; and products with natural or herbal ingredients, which can also be irritating.
- Stick to loose cotton clothing and keep irritated areas free of deodorants, perfumes, or adhesive bandages.
Gastrointestinal System Troubles
Breast cancer treatments can be unwelcome interlopers in the delicate environment of our gut, for several reasons: Chemotherapy can kill healthy bacteria that aid digestion. Chemo and radiation can inflame our intestine and digestive tract. CDK4/6 inhibitors and other treatments affect hormone levels, which can cause gas, bloating, diarrhea, constipation, or a combination thereof. And let’s not forget stress, which can even further skew the balance of bacteria and other microorganisms in your gastrointestinal (GI) system.
How to get relief
- Give your stressed-out system a break by steering clear of spicy foods, eating smaller meals more frequently, and prioritizing hydration, which can keep everything working more smoothly. I
- If your GI woes are really affecting your quality of life, talk with your care provider about medications or other measures that might help.
Metastatic Breast Cancer Treatment Side Effects
While many acute symptoms resolve after therapy ends, the long-term side effects of breast cancer treatment can persist or emerge years later. Regular monitoring by your healthcare team is essential for catching and managing these symptoms.
Heart and Lung Risks
Some breast cancer medications, particularly anthracyclines and anti-HER2 drugs, may cause physical damage to the heart as well as inflammation, raising your risk of cardiomyopathy and congestive heart failure. “Doctors are now trying to protect the heart by lowering the doses of those drugs or avoiding them altogether,” says Dr. Hershman, who adds that developing safer alternatives is a current area of focus for researchers.
CDK4/6 inhibitors, used to treat hormone receptor-positive types of cancer, as well as certain immunotherapies, may affect the heart’s electrical system, resulting in arrhythmias. They can also cause a rare but serious inflammatory lung condition called pneumonitis. Chemotherapy and radiation can also result in pulmonary inflammation and scarring.
If you start experiencing symptoms such as dizziness, shortness of breath, heart palpitations, chest pressure, sudden swelling of the limbs, or persistent coughing, follow up with your care team immediately.
How to get relief
- Because prevention is everything, regular visits with your doctor are essential. They may keep tabs by regularly administering EKGs, checking your blood pressure, cholesterol, and other factors that could affect your cardiovascular health, as well as monitoring your lung function.
- Make sure you talk to your doctor about heart-healthy lifestyle choices.
Swelling, Pain in Limbs and Joints
If your surgeon had to remove multiple lymph nodes from under the arm and/or deliver radiation to that site, you may experience lymphedema, a buildup of lymph fluid in the tissues that can cause uncomfortable swelling in your arms, hands, or legs.
On anti-estrogen treatments, joints tend to feel the loss of that hormone’s anti-inflammatory powers. “Aromatase inhibitors such as anastrozole are big culprits in terms of increasing joint pain,” Dr. Hershman says. Additionally, common taxane chemotherapy drugs can affect nerve endings, resulting in neuropathy, which can cause tingling, numbness, or other changes in sensation.
How to get relief
- For lymphedema: Light, supervised exercise can help improve circulation of lymphatic fluid, along with specialized physical therapy.
- For joint pain: Exercise can help. Other possibilities include omega-3 fish oil supplements under a doctor’s supervision and non-pharmaceutical treatments such as acupuncture.
- For neuropathy: Some medications can be prescribed for neuropathic pain. The most promising newer treatments involve treating the fingers and toes during chemotherapy infusion, either by compressing them or applying cold packs.
Sexual Health Dysfunction
Whether you’re going through treatments or you’re finished and trying to get back on track, it’s understandable to feel less than lusty. Stress has a way of dimming that internal pilot light, along with fatigue, indigestion, financial issues, and many other factors. And once again, hormones rear their powerful heads: Treatments that lower levels of estrogen and progesterone can also lower levels of lubrication and libido.
As for fertility, Dr. Hershman says, the news is promising: significant BCRF-supported research has shown that certain women of childbearing age who were receiving hormone therapy after breast cancer were able to pause therapy long enough to get pregnant, then safely resume treatment.
How to get relief
- If over-the-counter lubrication products aren’t doing the trick for dryness, you might be a candidate for a vaginal estrogen cream.
- For a non-pharmaceutical option, consider traditional couples’ counseling or joining a support group that focuses specifically on breast cancer and sexuality.
Empowering Your Healing Journey
Experiencing the side effects of breast cancer treatment can feel overwhelming, but you do not have to navigate them in silence. As research advances, so do the personalized strategies for managing both immediate symptoms and the long-term side effects of breast cancer treatment.
“I think the reassuring thing for a lot of patients is that some of these symptoms get better with time and the body adjusts,” says Dr. Hershman. Every person’s body is unique, and so symptoms can be profoundly interconnected. For instance, fatigue can lead to depression, which can then lead to a loss of libido. Finding the right relief often requires a collaborative trial-and-error process with your healthcare provider.
Whether you are adjusting to temporary physical changes or balancing the ongoing needs of metastatic breast cancer treatment side effects, your medical team is your greatest resource. Don’t be shy about sharing what’s bothering you, multiple times if necessary. And ask questions.
The one thing you should never do is pause or stop lifesaving therapies on your own. “These medicines really work,” says Dr. Hershman, “so it’s really important to work together to try to alleviate those side effects so you can stay on them.”
For more expert-backed information about breast cancer, visit BCRF’s About Breast Cancer website.
FAQ on Side Effects of Breast Cancer Treatment
How does managing metastatic breast cancer treatment side effects differ from early-stage treatment?
Since metastatic breast cancer requires ongoing, continuous therapy, side effect management focuses heavily on long-term sustainability rather than just getting through a finite period. Your care team will prioritize balancing disease control effectiveness with maintaining your daily quality of life, which may involve regularly adjusting dosages or integrating palliative care specialists into your routine.
Can long-term side effects of breast cancer treatment appear years after I finish my therapy?
Yes. While many acute symptoms resolve shortly after treatment ends, certain long-term side effects of breast cancer treatment—often referred to as “late effects”—can emerge months or even years later. These can include early-onset osteoporosis, late-onset cardiovascular issues from specific targeted therapies, or persistent neuropathy, making consistent, long-term follow-up care with your doctor essential.
Are natural supplements and vitamins safe for managing the side effects of breast cancer treatment?
You should always consult your oncologist before taking any over-the-counter vitamins or herbal supplements. While some natural remedies might seem like a harmless way to combat the side effects of breast cancer treatment, high doses of certain antioxidants, herbal teas, or supplements may actually interfere with how your body processes chemotherapy and endocrine therapies, potentially making your treatment less effective.
