How Does Breast Cancer Affect Your Body?

Medically Reviewed by Brunilda Nazario, MD on October 24, 2023
Written by Paul Frysh
4 min read

In most cases, the biggest life-changing effects of breast cancer come from the treatment, not from the disease. Early detection and therapy options make the outlook for most types of breast cancer very good.

But surgery, chemotherapy, and radiation -- while key parts of treatment -- can take a toll on your physical and mental health both just after the treatment as well as months or years later.

It's a common symptom of breast cancer and a side effect of its treatment. Your doctor might call it fatigue. It might last for months after treatment, sometimes even longer.

Your tiredness may ease if you:

  • Eat a well-balanced diet
  • Keep a healthy weight
  • Get enough sleep
  • Stay physically active

Chemotherapy, or “chemo,” can make your hair fall out, not only on your head but also all over your body. Chemo also can turn your skin dry, itchy, and flaky. Radiation might cause your skin to look and feel like sunburn around the treatment spot.

These effects may change how you feel about yourself. Some people might react visibly. Consider telling your loved ones and others beforehand about what you’re going through. Sometimes it may help to talk to a mental health counselor.

The good news is that after treatment, your skin returns to normal and your hair usually grows back. It’s possible that your hair could grow back with a slightly different feel and texture.

Surgeons sometimes remove your lymph nodes from the arm near the breast with the tumor. This can cause a fluid buildup (lymphedema) that makes your arm, chest, and belly feel swollen, stiff, and sore. A physical therapist can help lessen these effects.

Certain chemotherapy drugs, like docetaxel (Taxotere), can make your body to hold onto more fluid than it should. That also can make your arms or legs swell. Physical therapy may help. 

A group of estrogen-blocking breast cancer drugs called aromatase inhibitors (anastrozole, exemestane, letrozole) may make your bones more brittle. That may cause bone and joint pain.

Certain types of chemotherapy can also cause bone thinning. If you aren’t already in menopause, it may start prematurely.

Breast cancer itself can cause pain if it spreads to your bones. A specialized radiation treatment called radiotherapy can sometimes help. Ask your doctor about other treatment options like pain medications.

If you’ve had surgery for your cancer, the tissue around the cuts in your skin may scar and harden. The shape of your breast also may change. Some surgical cuts, like those used for a lumpectomy, can leave scars that fade but may not go away completely.

Your doctor can help prepare you for what to expect. You also might find it helpful to look at pictures of women who’ve been through this so you know what to expect.

It may help to talk to your sexual partner about the coming changes to your body, and let them look at and touch the scars. If your body’s changes take a toll on you or your relationship, it can help to talk with a mental health specialist.

Your sex drive may slow as your body changes from breast cancer or its treatment. Part of this could be body image, but tiredness, pain, and anxiety also might play a part.

You may have intercourse less often. Also, chemo and hormone therapy can lower your chances to get pregnant when you do have sex.

Talk to your doctor about a fertility specialist or mental health counselor if you need support.

Sometimes breast cancer spreads, or metastasizes, through the bloodstream to other parts of the body. It can lead to tumors in your brain, bones, liver, lung, and elsewhere. Complications may include blocked blood vessels, bone fractures, and pressure on the spinal cord.

Radiation therapy. In some cases it can cause pulmonary fibrosis, which scars your lung tissue. You might notice:

  • Dry cough
  • Trouble breathing
  • Chest pain

These symptoms typically show up 2-3 months after your treatment ends. It may first look like pneumonia, but antibiotics won’t help. Your doctor may prescribe steroids to treat your symptoms.

Chemotherapy. Certain chemo drugs can lead to heart problems, especially if you had existing heart problems. Other possible side effects of chemo include:

  • Hot flashes and irregular or missed periods
  • Foggy thinking
  • Memory loss
  • Nausea
  • Diarrhea
  • Consistent numbness, pain, or tingling in fingers or toes
  • Weight gain

Hormone therapy. If you have a type of tumor called estrogen and/or progesterone receptor positive, you might get hormone therapy drugs. Many of them can lead to weaker bones (osteoporosis). One drug, tamoxifen, may raise your risk for serious medical issues like stroke, blood clots, and uterine cancer. Tamoxifen also may cause:

  • Vaginal discharge
  • Weight gain
  • Hot flashes

Each woman responds differently to their breast cancer and treatments. It’s a good idea to keep track of your experience and update your doctors about your side effects. The sooner they’re aware, the better they can help you get your symptoms under control.