Side effects can be different for every person. The list that follows is not a complete catalog, so be sure to speak to your doctor about anything you're experiencing that feels out of the ordinary. To report suspected adverse reactions of MBC therapy, contact FDA at 1-800-FDA-1088 or fda.gov/medwatch.
Hot flashes
Hot flashes are associated with hormonal changes within your body and are a common side effect of treatments that use hormones. These changes can be caused by menopause or medication, and there are some prescription medicines that treat hot flashes. It may also help to avoid certain triggers, including:
- Alcohol
- Hot food
- Spicy food
- Caffeine
- Diet pills
- Hot tubs
- Saunas
- Hot showers
- Smoking
- Stress
Joint pain
Joint and muscle pain may arise from your treatment. For persistent pain, you can try:
- OTC medications
- Heat
- Swimming
- Yoga
- Massage treatments
- Strength-building exercises
Diarrhea
Diarrhea is a common condition caused by illness or infection, or as a side effect of medications. You have diarrhea when you have loose or watery stool at least three or more times per day. Diarrhea can lead to other health issues, including dehydration and malnutrition. Some tips to manage diarrhea include:
- Drinking as much fluid as you can tolerate, especially water, electrolyte beverages, apple juice, and clear broth
- After a day or two, try eating small, low-fiber solid foods, like bananas, rice, applesauce, and toast, while maintaining hydration and letting your care team know if diarrhea persists
Nausea and vomiting
Nausea and vomiting are common side effects during MBC treatment. Nausea and vomiting may be caused by specific cancer treatments, the use of certain pain medications, or anxiety. If you’re feeling these effects, talk to your doctor about what remedies may be available to help. Some ways to ease nausea and vomiting include:
- Eating small amounts of food throughout the day whenever you feel like you can
- Choosing plain foods like toast, cereal, pasta, soups, and broth
- Avoiding rich, greasy, and strong-smelling foods
- Taking slow sips of water, tea, ginger ale, and other clear liquids
Decrease in bone mass
A decrease in bone mass, also known as osteoporosis or a weakening of the bones, causes an increased risk of bone fractures. It may be caused by some MBC treatments or a drop in estrogen due to menopause. A bone density test can measure bone loss. To help reduce your risk of osteoporosis:
- Eat a balanced diet rich in calcium and vitamins
- Engage in weight-bearing exercise, such as brisk walking
- Avoid smoking and excessive alcohol consumption
Weight changes
Some MBC treatments may cause you to lose or gain weight. Keep a journal to monitor your weight and eating patterns and discuss any concerns with your treatment team. Your team may recommend:
- Supplementing your diet with extra protein and calories
- Consulting a dietitian or nutritionist for specific recommendations
- Lowering the amount of fat or calories in your daily diet, if you’re gaining weight
- Starting a program of regular, moderate exercise for further weight reduction
Vaginal dryness
Cancer therapy may cause vaginal dryness, leading to discomfort and more difficult or painful intercourse. There are numerous OTC water-based vaginal lubricants or moisturizers available that may help. Petroleum jelly should be avoided, as it may increase the risk of vaginal yeast infections.
Fatigue
Treatment-related fatigue can be physically, emotionally, and mentally draining and impact daily activities. Unlike normal tiredness that is relieved by rest, exercise, or a good night’s sleep, treatment-related fatigue can leave you feeling “wiped out” and make it hard to concentrate, even after getting plenty of rest. To help manage fatigue:
- Focus on important tasks first while you have the most energy
- Eat a balanced diet and stay hydrated
- Work on lowering your stress
- Get checked for anemia
- Engage in exercise
- Ask your care team for recommendations
Neutropenia
Some chemotherapy medicines can cause neutropenia, a condition caused by lower-than-normal amounts of neutrophils, a type of white blood cell. Neutrophils fight infection by killing harmful bacteria in the blood. Neutropenia can also happen when breast cancer has moved into the bones and has pushed out healthy bone marrow cells, an important source of white blood cells. Because white blood cells are needed to fight infection and disease, your doctor may prescribe you a medicine to boost your white blood cell counts. If your white blood cell counts remain too low on this medication, your doctor may adjust your cancer treatment.
To protect yourself against infection in your daily life, a few steps you can take include:
- Washing your hands often and well
- Avoiding crowds and sick people
- Wearing a mask in a group setting
- Cleaning and bandaging any cuts or scrapes
- Cooking foods thoroughly
Visit breastcancer.org/treatment-side-effects for more information on side effects of MBC treatments.
