How Breast Cancer Can Impact You from Head to Toe

BCRF’s guide to the most common side effects of breast cancer, plus expert advice for starting to get relief

Every person’s experience with breast cancer is as individual as they are—but whatever your diagnosis, breast cancer will almost certainly affect more than your breasts. The disease, treatment, and aftermath can cause a wide range of symptoms, both physical and psychological. However, there’s hopeful news too: More research and clinical efforts are being poured into learning about those side effects, determining the risk-benefit ratio of various treatments for each patient, and improving survivorship and quality of life overall.

“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 BCRF Scientific Advisory Board Member Dr. Dawn Hershman. “But over time, we’ve developed newer treatments, and each treatment provides some kind of incremental improvement. Now we can focus more on how to measure the side effects of treatment and determine whether the benefits are worth the risks.”

Why does breast cancer impact other parts of a woman’s body? One major reason may surprise you: As more (and more sophisticated) treatments become available and are offered in various combos with other treatments, “each one presents a new constellation of side effects,” Hershman says.

Another major reason may not surprise you at all: hormones. Sex hormones—those powerful chemical messengers that exert such profound control over our energy, our joints and muscles, our metabolism, and more—also play a big role in breast cancer treatment, since about 80 percent of diagnoses are hormone receptor–positive.

“One of the most common reasons people have side effects is that breast cancer treatments mess with their hormones, whether it’s chemotherapy or hormone therapies like tamoxifen or aromatase inhibitors that block or reduce the production of estrogen,” Hershman says. “That can affect cognition, sleep, physical endurance, sexual health, and so many other issues.”

The upshot of all this (and there is one!) is that 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.

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
The key is to control the controllables. “We can’t necessarily change everything when it comes to your treatment measures, but we need to pay attention to the things we can change,” Hershman says. That probably means lifestyle factors such as:

• Making sure you get an iron-rich diet (including fruits and vegetables, beans, and leafy greens), especially if you’re anemic—but talk to your doctor before you take any iron supplements. Research indicates that iron supplements may interfere with certain breast cancer treatments or increase your chances of recurrence.
• Moving regularly, even if a short and gentle walk or yoga session is all you can handle.
• Practicing good sleep hygiene: Keep your bedroom cool and dark, avoid afternoon caffeine breaks or screens at bedtime. If you’re really struggling with insomnia, which can affect not only your energy but your mental health, cognitive capabilities, and even relationships, Hershman suggests considering cognitive behavioral therapy for insomnia (CBT-I). Though CBT-I is the recommended first-line treatment for chronic insomnia, ask your doctor if medication might also be an option.

Cognitive Impairment

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. You refer to an actor as “the guy who was in that thing the one time.” Although this forgetfulness/fuzzy thinking among people with cancer is often called “chemo brain,” researchers aren’t entirely sure why it happens and theorize that it could also be caused by radiation or other cancer treatments, chronic stress, the physiological changes brought on by the disease itself—or a combination of all the above.

Breast cancer treatments may make the story even more complicated, because declining levels of estrogen have been proven to contribute to memory deficits. 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.

How to get relief
For many patients, chemo brain and other cognitive impairments 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.

• Again, maintaining healthy lifestyle habits is vital: Sleep, movement, and nutritious food are important factors in shoring up anyone’s cognitive powers, but that may be especially true for those on anti-estrogen therapies.
• When you’re already feeling overwhelmed, you might not be excited about adding stress-relief techniques to your to-do list. That said, practices like meditation have demonstrably improved both the outlook and cognitive capabilities of breast cancer patients with “chemo brain.” BCRF has research-backed resources here.
• Become a unitasker. Regardless of our health status, most of us aren’t very good at juggling multiple activities. 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. So, try a mindset shift and embrace focusing on one thing at a time.
• Track the times and situations when you typically feel sharpest, and vice versa. If you’ve never been a bright-and-early type, save your more thought-intensive tasks for later in 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,” Hershman says, adding that both tamoxifen and aromatase inhibitors can trigger mood changes. When we’re low on estrogen, we’re also low on feel-good neurotransmitters like serotonin, which is important to keep in mind when you find yourself feeling especially blue, or cranky, or filled with white-hot rage.

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,” 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
It bears repeating: Sleep well, eat well, and move when you can.

• If you’re up for getting back into an exercise routine, the American College of Sports Medicine offers research-based exercise regimens for various cancer-related issues. Studies show that three weekly 30- to 60-minute sessions of moderate to vigorous aerobic activity can help alleviate depression.
• Antidepressants can help. If you’re open to the idea, Hershman recommends exploring it with your oncologist or a psychopharmacologist, keeping in mind that certain antidepressants can not only improve mood but reduce other side effects: “Some can help with hot flashes, which may also help with sleep, and some may improve joint pain,” Hershman says. “You also want to consider your personal goals. For instance, sometimes people are depressed because they’ve lost their libido, and some medicines make that worse—so we have to be thoughtful about what we’re trying to fix.”
• Whether or not you opt for medication, therapy can be helpful. Psychodynamic therapy takes a more introspective approach that encourages reflection about how past experiences have shaped your current behavior, while cognitive behavioral therapy focuses on the way changing your present thoughts can influence your feelings.
• You might also consider complementary mind-body practices such as tai chi, yoga, or hypnotherapy.

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 chemo drugs, which target rapidly growing cells, including those in your hair follicles. Some medications, Hershman says, have more significant effects on the scalp, including more hair loss and slower regrowth, so you may want to bring concerns up with your doctor. Longer-term hair loss may also be related to simultaneous hormonal changes, she adds.

A less widely discussed concern is the loss of the hair in places besides your head, which often serve important protective functions. 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, which are there to help contain the products of sniffling and sneezing. 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. The idea is to attempt to prevent hair loss by constricting the blood vessels and keeping the chemo drugs from reaching the follicles. “Even if it doesn’t preserve all the hair, there’s some evidence that it can help hair grow back faster afterward,” Hershman says.
• The prescription eyelash regrowth treatment bimatoprost (Latisse^®) may be an option for breast cancer patients.
• For hormone-related hair loss, she adds, the topical over-the-counter drug minoxidil (a.k.a. Rogaine^®) may help.
• There’s also some evidence that after your treatment is over, biotin supplements can help encourage regrowth of your hair and nails, which can develop discoloration or ridges, split, peel, or come off completely. But talk to your doctor before starting any supplements.
• Cooling gloves and socks may help prevent nail damage as well.

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, and you should begin 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. (For specific brands, check with your radiation nurse or oncologist).
• Avoid antibacterial soaps, which can be drying; moisturizers with lanolin, which comes from animals that produce wool and 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.

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 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.

How to get relief
Because prevention is everything, your doctor should be keeping tabs by regularly administering EKGs; checking your blood pressure, cholesterol, and other factors that could affect your cardiovascular health; and monitoring your lung function. Consider also:

• Making sure you talk to your doctor about heart-healthy lifestyle choices.
• And if you start experiencing symptoms such as dizziness, shortness of breath, heart palpitations, pressure in the chest, sudden swelling of the limbs, or persistent coughing—which could indicate trouble with your heart or your lungs—follow up with your care team immediately.

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 our hormone levels, which can cause gas, bloating, diarrhea, constipation, or a combo thereof. And let’s not forget stress, which can even further skew the balance of bacteria and other microorganisms in your GI system, leading to a host of less-than-pleasant digestive issues.

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.
• And if your GI woes are really affecting your quality of life, talk with your care provider about medications or other measures that might help.

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, insurance deductibles, and many other factors that may be part of your breast cancer experience. And once again, hormones rear their powerful heads: Treatments that lower our levels of estrogen and progesterone can also lower our levels of lubrication and libido.

As for fertility, 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 with no adverse effects over the short term.

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. Although topical estrogen use was long considered too risky for patients who had been diagnosed with hormone receptor–positive breast cancer, current research doesn’t support that conclusion, Hershman says. “Studies have shown that patients with severe symptoms can use these low-dose topical agents for short periods without increasing their risk of cancer recurrence.”
• Limited research indicates that the hormone-free drug flibanserin (Addyi^®), designed to treat “hypoactive sexual desire” in premenopausal women, can be beneficial for breast cancer patients.
• For a non-pharmaceutical option, consider therapy. This could mean traditional couples’ counseling for you and your partner or joining a support group that focuses specifically on breast cancer and sexuality.

Swelling and 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.

Fortunately, this side effect is diminishing along with advances in breast cancer treatment. “One of the biggest improvements is that doctors now know we don’t necessarily need to take out as many lymph nodes as we once did,” Hershman says. “Cutting back on those surgeries has had a big effect on reducing lymphedema rates.” Other advancements include techniques such as lymph venous bypass surgery, in which lymphatic veins are connected to nearby blood vessels, bypassing blocked or damaged veins.

On anti-estrogen treatments, our 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,” Hershman says. “We pay attention to that because it can be a major reason why people stop taking their medicine.”

Common taxane chemotherapy drugs like Taxol^® or Taxotere^® can affect the nerve endings, resulting in neuropathy, which causes tingling, numbness, or other changes in sensation. Often felt in the fingers or toes, the condition can progressively worsen, increasing sensitivity to heat or cold.

How to get relief

• For lymphedema: Light, supervised exercise can help improve circulation of lymphatic fluid, along with specialized physical therapy, which may involve a combination of massage, compression, and exercises.
• For joint pain: Exercise can help. Other possibilities include omega-3 fish oil supplements under a doctor’s supervision, duloxetine (a prescription drug used to treat depression and general anxiety disorder, which has proven an effective treatment for achy joints), and non-pharmaceutical treatments such as acupuncture. “We did a very large, randomized trial looking at acupuncture to reduce joint pain, and it can be very effective,” Hershman says.
• For neuropathy: The anticonvulsant medication gabapentin is often prescribed for neuropathy, with varying degrees of success. The most promising newer treatments, says Hershman, have involved treating the fingers and toes during chemotherapy infusion, either by compressing them or applying cold packs or cold socks and gloves.

A Note of Encouragement

“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 Hershman. Because people are complicated, everyone is unique, and symptoms can be profoundly interconnected (for instance, fatigue, which leads to depression, which leads to lost libido), you and your health care provider may need to go through a few rounds of trial and error. But don’t be shy about sharing what’s bothering you, multiple times if necessary.

The one thing you don’t want to do is pause or stop your treatments. “These medicines really work,” says 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.