What Is the Difference Between Chemotherapy and Targeted Therapy?

Chemotherapy and targeted therapy are both treatments that attack cancer cells. Targeted therapy is less toxic to healthy cells than chemo. Both options are often done in conjuntion with other treatments, such as radiation (pictured).

Both chemotherapy and targeted therapy are types of cancer treatments.

What Is Chemotherapy?

Chemotherapy (also called "chemo") is a type of cancer treatment that uses drugs to kill cancer cells (cytotoxic medications). 

Chemotherapy targets cells at different phases of the cell life cycle. Cancer cells are usually fast-growing, so chemotherapy drugs can help stop the life cycle of cancer cells. However, chemotherapy medications can’t distinguish between healthy cells and cancerous cells so normal cells are also damaged with chemotherapy. Most normal cells can recover from the effects of chemotherapy over time, but because cancer cells are mutated, they usually do not recover. Doctors try to find a balance between killing the cancer cells and sparing the healthy cells. 

Chemotherapy may be used alone or in combination with surgery, radiation, or immunotherapy.

What Is Targeted Therapy?

Targeted therapy is a cancer treatment that targets specific cancer cells without harming normal cells. Different types of cancer cells have different gene changes and proteins or enzymes that send messages to tell the cancer cell to grow and replicate. Targeted therapies are drugs that target the proteins or enzymes to block the messages, causing the cancer cells to stop growing or to destroy themselves. 

Types of targeted therapies include: 

• Angiogenesis inhibitors
• Monoclonal antibodies?
• Proteasome inhibitors
• Signal transduction inhibitors

Technically, targeted therapy is a type of chemotherapy, but it doesn’t work the same way. 

Differences between chemotherapy and targeted therapy include:

• Traditional chemotherapy is cytotoxic to cells, meaning it damages healthy cells in addition to cancer cells
• Targeted therapy affects cancer cells, leaving normal, healthy cells mostly intact
• Traditional chemotherapy kills cancer cells that already exist
• Targeted therapy can block cancer cells from replicating themselves, meaning it can stop new cells from being produced

Chemotherapy destroys cells in the body, and may attack both cancerous and non-cancerous cells, resulting in side effects such as: 

• Hair loss
• Fatigue
• Easy bruising and bleeding
• Infection
• Low red blood cell counts (anemia)
• Nausea 
• Vomiting
• Diarrhea
• Constipation
• Changes in appetite
• Mouth, tongue, and throat problems such as sores and pain with swallowing
• Nerve problems (numbness, tingling, and pain)
• Skin and nail changes 
• Urine and bladder problems
• Weight changes
• “Chemo brain,” which affects concentration and focus
• Kidney problems
• Mood changes
• Changes in sex drive and sexual function
• Fertility problems

Side effects of targeted therapies include: 

• Skin changes
  • Rash
  • Sensitivity to sunlight (photosensitivity)
  • Changes in how the skin feels – may feel like it’s sunburned
  • Dry skin
  • Itching 
  • Swollen, red, painful sores around the fingernails and toenails
  • Brittle nails that grow more slowly
  • Skin may turn a yellowish color during treatment or become darker
  • Hand-foot syndrome (HFS) 
    • Painful sensitivity, tingling, or numbness in the hands and feet 
    • Redness and swelling of palms of the hands and the soles of the feet
    • Redness may look like sunburn and may blister
    • In severe cases, blisters can become open sores
    • Skin can become dry, peel, and crack
• Hair changes
  • Scalp hair may become thin, dry and brittle, or even curly
  • Bald patches or complete loss of scalp hair may occur with long-term use
  • Facial hair for both men and women may grow faster than usual, including thicker, longer, curly eyebrows and eyelashes that may need trimming
  • In some men, facial hair growth slows
  • Eyebrows may thin 
  • Hair may become darker or may turn a yellowish color
  • Hair loss
• Changes in and around the eyes
  • Eye burning, dryness, or redness
  • Red, tender, swollen eyelids
  • Lashes may become crusty
  • Eyelids may turn inward or outward
• High blood pressure (hypertension)
• Slow wound healing
• Bleeding or blood clotting problems
  • Bruising or bleeding
  • Gastrointestinal bleeding – blood in vomit or stool (serious)
  • Blood clots in the lungs and legs - sudden swelling, pain, or tenderness in the arm or leg (serious)
  • Heart attacks and strokes - chest pain, sudden shortness of breath, vision problems, weakness, seizures, or trouble speaking (serious)
• Heart damage
  • Chest pain
  • Increased coughing
  • Trouble breathing (especially at night)
  • Rapid weight gain
  • Dizziness
  • Fainting
  • Swelling in the ankles or legs
• Autoimmune reactions (uncommon but can be serious)
• Swelling in the face (especially around the eyes), feet and legs, and hands
• Nausea and vomiting
• Diarrhea or constipation
• Mouth sores
• Shortness of breath or trouble breathing
• Cough
• Fatigue
• Headache
• Damage to organs such as the thyroid gland, liver, or kidneys
• Allergic reactions (while getting an IV drug)
• Increased risks of infections
• Second cancers