Side Effect Management

Breast cancer treatment can cause a range of side effects that may affect your daily life. This section discusses common side effects and offers strategies to help you manage them.

Side effects can be different for everyone. It is important to talk openly with your healthcare team about any symptoms you experience. They can help you find ways to feel more comfortable and adjust your treatment plan if needed. Most side effects can be managed, and there are many tools available. Staying on your treatment as planned is important for the best chance of success. If you are considering stopping your treatment, be sure to speak with your doctor before you make any changes.

Managing side effects

Side effects from cancer treatment can be uncomfortable and, in some cases, serious, potentially interfering with your care. It’s important to work with your healthcare team to find effective strategies for managing symptoms and maintaining your well-being.

For more information, visit:

• Questions & Experts: A Medical Oncologist and Oncology Pharmacist Answer Your Questions About Systemic Side Effect Management
• Side Effects | Canadian Cancer Society

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Bone health | Cancer-related brain fog | Digestion: constipation and diarrhea | Depression and anxiety | Fatigue | Febrile neutropenia | Hand-foot syndrome | Hair loss | Lymphedema | Menopausal symptoms | Mouth sores | Nausea and vomiting | Nail changes | Neuropathy | Pain | Skin changes

Bone health

Some treatments, including chemotherapy and hormonal therapies, can weaken bones. If cancer has spread to the bones (called bone metastases), it can further increase the risk of bone loss. Osteoporosis often develops without symptoms, but possible signs include unexplained weight loss, posture changes, upper back curvature, bone tenderness, or a decrease in height.

A bone density scan can check for bone loss. If needed, your doctor may recommend bone-strengthening medications to help prevent fractures. Some research suggests these medications may also lower the risk of breast cancer recurrence in the bones. Talk to your oncologist to see if this option is right for you.

Managing bone health

• Get enough calcium and vitamin D through food or supplements
• Stay active with weight-bearing exercises like walking, dancing, or stair climbing
• Maintain a healthy weight to reduce stress on bones
• Prevent falls by wearing well-fitting shoes and keeping living spaces free of tripping hazards

» Related reading from Our Voices Blog: 

• Early Breast Cancer and Bone Health: What You Need to Know
• Advanced Breast Cancer and Bone Health: What You Need to Know

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Cancer-related brain fog

Cancer-related brain fog is a common side effect of cancer and its treatment. You might forget names, lose track in conversations, or have trouble concentrating.

Managing Brain Fog

• Stay organized: Use a calendar or planner
• Keep your mind active: Try puzzles, games, or hobbies
• Support brain health: Prioritize rest, movement, and nutrition
• Track symptoms: Journal cognitive challenges to discuss with your doctor

» Related reading from Our Voices Blog:

• Tips for managing cancer-related brain fog

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Digestion: constipation and diarrhea

Constipation: Difficulty emptying the bowels is a common side effect of chemotherapy, hormonal therapy, and targeted therapies.

Diarrhea: Frequent, watery bowel movements can result from chemotherapy or radiation and may cause weight loss, fatigue, and dehydration.

Managing Digestive Issues

• Stay hydrated: Drink plenty of fluids, especially for diarrhea
• Adjust your diet: Eat digestion-friendly foods and avoid triggers
• Increase fiber gradually: Prevent discomfort by adding fiber slowly
• Consider medications: Consult your doctor about treatment options
• Monitor symptoms: Track bowel habits and report concerns

» Related reading from Our Voices Blog:

• Constipation: A hard truth
• Diarrhea – The opposite of constipation

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Depression and anxiety

About one in four people with breast cancer experience depression or anxiety. While occasional sadness or worry is normal, persistent mood disturbances may need support and treatment.

Signs of depression

Clinical depression, as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), involves at least two weeks of persistent sadness or loss of interest in daily activities, plus five or more of the following symptoms:

• Persistent sadness, emptiness, or irritability
• Loss of interest in most activities
• Significant changes in weight or hunger
• Trouble sleeping or sleeping too much
• Fatigue or low energy
• Feelings of guilt or worthlessness
• Difficulty concentrating or indecisiveness
• Thoughts of death or suicide

Signs of anxiety

An anxiety disorder is diagnosed when excessive worry or fear lasts six months or more, with at least three of the following symptoms:

• Restlessness or feeling on edge
• Fatigue or exhaustion
• Difficulty concentrating or mental “blanks”
• Irritability
• Muscle tension, aches, or soreness
• Trouble sleeping

Managing depression and anxiety

• Talk therapy: Individual or group therapy to build coping strategies
• Medication: Antidepressants or anti-anxiety treatments may help
• Mindfulness and relaxation: Meditation, deep breathing, or yoga
• Physical activity: Regular exercise boosts mood and energy
• Support groups: Connecting with others for emotional support

» Related reading from Our Voices Blog:

• Depression, anxiety and ways to cope
• Overcoming the lasting side effects of breast cancer
• How I regained control of my life when breast cancer made me feel like I had lost it

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Fatigue

Fatigue is a common side effect of surgery, radiation therapy, chemotherapy, and even cancer itself. It can also be worsened by factors such as depression, stress, poor nutrition, sleep disruptions, and other medical conditions.

Managing fatigue

• Focus on important tasks to save energy
• Try gentle exercise like walking or yoga
• Take short naps but maintain good nighttime sleep habits
• Eat a balanced diet to restore energy
• Enjoy relaxing activities like reading, music, or meditation

For more information, watch: From Fatigue to Vitality: Fueling Your Energetic Potential Webinar

» Related reading from Our Voices Blog:

• Tips for managing fatigue
• Cancer-related fatigue Q&A
• A running thread

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Febrile neutropenia

Neutropenia, or low white blood cell count, is a common side effect of chemotherapy that increases the risk of infection. White blood cells help fight bacterial infections, so when levels are low, the body may struggle to respond to illness.

A fever during neutropenia is a medical emergency because the body cannot effectively fight infection on its own. Symptoms of febrile neutropenia may include:

• Fever
• Shaking chills
• Night sweats
• Nausea or vomiting
• Swelling
• Headache
• Neck stiffness

Managing febrile neutropenia

• Go to the hospital immediately if you experience a fever
• Follow treatment adjustments like delaying chemotherapy or taking medications
• Prevent infection by washing hands and avoiding exposure to illness

For more information, watch: Managing the Side Effects of Chemotherapy 

» Related reading from Our Voices Blog: 

• Ask an expert: febrile neutropenia explained

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Hand-foot syndrome

Hand-foot syndrome is a side effect of certain chemotherapy drugs that damage small blood vessels in the hands and feet, causing redness, swelling, tingling, burning, peeling skin, blisters, and pain.

Managing Hand-Foot Syndrome

• Apply a cold compress: Use an ice pack wrapped in a towel for 15–20 minutes
• Avoid excessive heat: Limit hot showers, saunas, and extreme temperatures
• Reduce pressure: Minimize activities that strain your hands and feet
• Moisturize regularly: Use fragrance-free creams to prevent dryness and cracking
• Manage pain: Ask your doctor about over-the-counter pain relievers

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Hair loss

Hair loss from chemotherapy or radiation can be emotionally challenging. Wigs, hats, and scarves can help you feel more comfortable and confident.

Managing hair loss

• Consider a wig early: Matching your natural hair before treatment can be helpful
• Explore head coverings: Hats, scarves, and turbans offer warmth and style
• Be gentle: Use mild shampoos and avoid excessive brushing or heat styling
• Protect your scalp: Apply sunscreen or wear a soft covering outdoors
• Check insurance: Some plans cover wigs with a prescription

To find a wig boutique near you, visit the Canadian Cancer Society’s Community Services Locator.

» Related reading from Our Voices Blog:

• Getting Through Hair Loss Following a Breast Cancer Diagnosis

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Lymphedema

Lymphedema is swelling, usually in the arm or leg, that happens when lymph fluid builds up. This often occurs after lymph nodes are removed during breast cancer surgery. When the lymphatic system is blocked or damaged, fluid can’t drain properly, leading to swelling and discomfort.

Managing lymphedema

While there is no cure, there are effective ways to manage symptoms. These include compression garments, manual lymph drainage (a type of gentle massage), exercise, and skincare routines.

Learn more from the Canadian Lymphedema Framework.

Educational resources

• Questions & Experts: A Lymphedema Therapist Answers Your Questions about Breast Cancer-Related Lymphedema
• Questions & Experts: A Certified Lymphedema Therapist Answers Your Questions About Breast Cancer-Related Lymphedema
• Webinar: Advancements in Care for Breast Cancer Related Surgery - Reconstruction and Lymphedema

» Related reading from Our Voices Blog:

• Is Your Swollen Arm a Sign of Lymphedema?
• Surviving Breast Cancer and Living with Lymphedema
• Breast Cancer Related Lymphedema Part 1: Risk Factors
• Breast Cancer Related Lymphedema Part 2: Early Signs, and Treatments

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Menopausal Symptoms

Menopausal symptoms can occur as a side effect of hormonal therapy. Common symptoms include hot flashes, mood swings, and sleep problems.

Managing hot flashes

• Stay active: Regular exercise, like walking, running, swimming, or biking can help
• Wear breathable fabrics like cotton
• Dress in layers for easy temperature control
• Keep ice water nearby for quick relief
• Take a cool shower before bed to improve sleep
• Use quick cooling methods, like standing briefly in front of an open fridge

If hot flashes persist, talk to your oncologist about prescription options.

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Mouth sores (oral mucositis)

Mouth sores can be a side effect of radiation or chemotherapy, causing pain, difficulty speaking, eating, swallowing, and even breathing. In some cases, they may also lead to infections.

Managing mouth sores

• Maintain good oral hygiene to help prevent sores
• Rinse with club soda or prescribed mouthwash, especially if at risk
• Consult your healthcare team for treatments to relieve pain and prevent infection

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Nausea and vomiting

Nausea and vomiting can result from chemotherapy, radiation, certain anti-cancer drugs, and even anxiety. If vomiting becomes severe, it can lead to dehydration, which may disrupt your cancer treatment.

Managing nausea and vomiting

• Work with your healthcare team to find effective strategies
• Ask about anti-nausea medications (anti-emetics) to prevent and treat symptoms
• Stay hydrated by drinking fluids and replenishing electrolytes
• Manage nausea early to prevent complications

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Nail changes

Chemotherapy can cause nail changes, such as bruises, blemishes, or thinning and brittleness. These changes can increase the risk of infection and may worsen lymphedema.

Managing nail changes

• Keep nails trimmed and clean to reduce infection risk
• Wear gloves for protection during housework or gardening
• Report concerns or significant changes to your healthcare provider

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Neuropathy

Neuropathy is a side effect of chemotherapy and radiation that causes numbness, tingling, and discomfort in the hands and feet. It can also reduce sensitivity to hot and cold, lead to muscle weakness, cramping, and cause balance problems.

Managing neuropathy

• Try treatments like medications, massage, acupuncture, or transcutaneous electrical nerve stimulation (TENS) therapy
• Avoid tight shoes and extreme temperatures to reduce discomfort
• Stay active to improve strength and mobility
• Take safety precautions to prevent falls and injuries. Keep spaces well-lit and free of hazards
• Ask about cold therapy (ice baths or frozen gloves) during chemotherapy
• Treatment adjustments may help so it’s important to report symptoms to your doctor

» Related reading from Our Voices Blog:

• Helping you live better with Chemo Induced Neuropathy
• Nerve damage is a little-known side effect of radiation

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Pain

Pain can result from cancer or its treatments, affecting areas like the back, bones, joints, abdomen, chest, muscles, and head. Chronic pain may also develop after a mastectomy or radiation, leading to tightness and tissue shrinkage.

Managing pain

• Explore treatments like medications, massage, physiotherapy, and psychological support
• Work with your doctor or pain specialist to find effective pain management strategies
• Pain may be ongoing, but many interventions can provide relief and improve comfort

» Related reading from Our Voices Blog: 

• 6 ways to manage joint pain

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Skin changes

Cancer treatments can cause skin changes, including rashes, dryness, itchiness, hair loss, mouth sores, skin darkening, light sensitivity, and skin growths.

Managing skin changes

• Wash gently with mild soap and lukewarm water
• Moisturize twice daily with a thick, fragrance-free, alcohol-free cream
• Use an electric shaver instead of a razor if shaving is needed
• Wear loose-fitting clothing to reduce irritation
• Choose gentle detergents without dyes or perfumes
• Protect your skin from the sun with sunscreen and clothing

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Medical Review by Roochi Arora, MD, FRCPC, August 2025

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