Understanding Chemotherapy: Side Effects, Timing, and How to Manage Them

by Celia Chen  MScPT
Registered Physiotherapist
updated Apr 13, 2026

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Chemotherapy is a common and effective cancer treatment, but it often comes with side effects that affect the entire body. These can feel overwhelming, especially when you’re not sure what to expect. This guide will help you understand what side effects feel like, when they happen, how long they last, and what you can do about them, including how physiotherapy can help you feel more like yourself again.

 

Types of Cancer Treatment (Why Side Effects Differ)

Not all “chemo” is the same. It is important to know that there are 3 main categories, and each affects the body differently. This is why knowing your specific treatment matters since the side effects vary a lot and they affect the body differently.

1. Systemic Chemotherapy

This is the most common type. It travels through the bloodstream usually via IV and targets fast growing cells (including both cancer and healthy cells). This is why it has the most widespread side effects

2. Targeted Chemotherapy

This is more precise as it targets specific molecules or pathways that cancer cells use to grow. Side effects are different, less widespread, but can still impact joints, hormones, skin and energy levels.

3. Immunotherapy

This form of treatment helps your immune system recognize and attack cancer cells. Sometimes the immune system becomes overactive and starts affecting healthy tissues, causing inflammation in different parts of the body

 

When is Chemotherapy Given?

Adjuvant (after primary treatment)
Given after surgery or radiation to kill remaining cancer cells

Neoadjuvant (before primary treatment)
Given before surgery or radiation to help shrink tumours and control the spread of disease

Ongoing Treatment
Used in metastatic or advanced cancer to manage disease over time

Typical Timeline:

Most go through treatment in cycles often lasting 6 months, and cycles are spaced approximately 3 weeks apart to allow the body to recover between sessions

 

When Do Side Effects Start and How Long Do They Last?

Early side effects:
start during treatment and can last up to 6 months after (including fatigue, nausea, and immune suppression)

Late side effects:
symptoms show up 2-3 years post treatment (often involve nerves, heart, or hormones)

Long term side effects:
symptoms are ongoing and can persist for multiple years after treatment

 

Systemic Chemotherapy: Side Effects

This treatment targets all rapidly dividing cells, thus it has widespread effects

1.       Bone Marrow Suppression (Myelosuppression)

• Chemotherapy can reduce blood cell production
• Decrease in red blood cells -> anemia and fatigue
• Decrease in white blood cells -> higher infection risk
• Decrease in platelets -> higher bleeding/bruising risk

Support strategies:

• pacing, infection precautions, and dietitian support

2.       Peripheral Neuropathy

• Numbness, tingling, burning (in hands and feet)
• Can affect balance, walking, coordination and daily function
• Often dose dependent and cumulative and may appear after treatment ends

How Physiotherapy helps:

• Exercise therapy is one of the most evidence-supported interventions. Moderate intensity weight-bearing aerobic exercise helps improve nerve health and circulation, enhance motor control and coordination, and reduces symptom severity over time
• Balance and proprioceptive training to reduce fall risk
• Sensory re-education (desensitization) used to calm hypersensitivity and improve sensory tolerance through exposure to different textures
• Modalities such as TENS and/or pulsed ultrasound can help modulate symptoms, but are not standalone treatments
• External supports such as compression garments and kinesiology taping can be used to improve comfort and function during daily activities

3.       Cardiotoxicity

• Some treatments can affect heart function and can lead to cardiomyopathy

How Physiotherapy helps:

• Supervised aerobic conditioning programs monitoring heart rate, exertion, and symptoms
• Gradual return to activity and improve overall cardiovascular tolerance

4.       Gastrointestinal and Genitourinary Effects

• Poor nutrient absorption
• Diarrhea or constipation
• Bladder and bowel dysfunction

How Pelvic Floor Physiotherapy helps:

• Bladder and bowel retraining, strategies to address urgency, incontinence, or incomplete emptying
• Pelvic floor muscle training and coordination

How a Dietitian helps:

• Manage diarrhea/constipation through nutrition
• Support gut health and nutrient absorption
• Maintain energy and weight during treatment

5.       Cancer related fatigue

• This is the most common side effect. This type of fatigue can affect your ability to work, exercise and even socialize. It is a persistent, extraordinary exhaustion that does not improve with sleep or rest and contributes to high levels of distress

How Physiotherapy helps:

• graded exercise program that includes aerobic and resistance training
• use energy conservation strategies (e.g. pacing, prioritization)
• improve cardiovascular efficiency and reducing perceived effort so daily tasks feel easier
• prevent deconditioning, which worsens fatigue

6.       Cognitive Dysfunction (“Chemo Brain”)

• Short term memory lapses
• Difficulty learning new things, multitasking and concentrating
• Slower thinking and processing, trouble word finding

Support strategies:

• Exercise has shown to support brain function
• Sleep and fatigue management
• Establishing routine and cognitive pacing strategies

 

Targeted Chemotherapy: Side Effects

This treatment focuses on specific cancer mechanisms such as:

• Blocking growth receptors
• Inhibiting enzymes
• Preventing blood vessel formation (angiogenesis)
• Interfering with hormone pathways

Common Side Effects

1.       Musculoskeletal

• Joint pain and stiffness (arthralgia)
• Tendon and ligament irritation

How Physiotherapy helps:

• Mobility and range of motion exercises
• Manual therapy, soft tissue release and stretching
• Resistance training to prevent muscle atrophy during treatment
• Load management to avoid flare-ups and restore independence in activities of daily living

2.       Hormonal Effects

• Sudden menopause-like symptoms such as hot flashes, night sweats and irregular periods
• Decreased bone density
• Muscle and tendon weakness

How Physiotherapy helps:

• Weight bearing and resistance training to stimulate bone health
• Postural and balance training to reduce fall and fracture risk

Other Effects:

3.       Gastrointestinal (Diarrhea, gut issues and poor nutrient absorption)

4.       Skin changes (Rashes, dryness, and nail changes)

5.       Cardiovascular effects (less common but serious)

Dietitian support is key for managing GI symptoms and maintaining nutrition

 

Immunotherapy: Side Effects

These side effects are often inflammatory or autoimmune type reactions

Common Side Effects:

1.       Endocrine: thyroid dysfunction, adrenal insufficiency, pituitary inflammation

2.       GI: colitis (diarrhea, abdominal pain)

3.       Skin: rashes, itching

4.       Pulmonary: pneumonitis (cough, shortness of breath)

5.       Neurological: neuropathy, weakness, coordination issues

6.       Musculoskeletal: joint pain and inflammation

How Physiotherapy helps:

• Vestibular physiotherapy to address any dizziness or vertigo
• Static and dynamic balance training
• Strength and mobility work to maintain function

 

Chemotherapy can feel unpredictable, but understanding the side effects can make it less overwhelming. While side effects are common, they are also manageable. With the right support team, you can reduce symptoms, maintain strength and independence, and improve your overall quality of life during and after treatment.