By Marshalee George, Kimlin Tam Ashing

Radiation, or radiotherapy, involves the use of a beam of high-energy rays to kill cancer cells in your breast or lymph nodes under your armpit or chest wall. Radiation therapy is usually recommended after a lumpectomy, when the breast cancer has spread to the lymph nodes under the armpit, or after a mastectomy and the surgical margins are still positive for cancer.

Side effects

Side effects from radiation can be immediate (also called acute or early side effects) or long-term, occurring after six months of radiation treatment.

Immediate side effects are typically related to skin reactions that may occur during radiation and may last for up to six months. If you are exposed to the sun a lot without wearing sunscreen, for example, you are more likely to get sunburn. Similarly, radiation will increase your risk of skin damage and other side effects that include the following:

  • Sunburn.
  • Darkening.
  • Tenderness and/or itching of the skin in the treatment area.
  • Peeling or flaking of the skin as treatment goes on, and this may result in a red, blistering, weepy skin reaction. Note that many individuals do not experience this symptom, and your radiation oncologist may provide you with special topical creams to use during radiation to reduce the risk of peeling and blisters from developing.

Side effects that may occur immediately and long-term

  • Pain in the breast or chest area in the form of aches, twinges, or sharp shooting pain
  • Swelling of the breast or chest
  • Stiffness or discomfort around the breast/chest or shoulder
  • Fatigue or tiredness
  • Hair loss under the armpit or chest area
  • Sore throat
  • Hardening of the tissue, known as fibrosis, caused by the accumulation of scar tissue
  • Dry cough or shortness of breath because of inflamed treatment area

Serious side effects that can occur later

  • Weakening of the bones under the treated area, which can lead to rib and collarbone fractures
  • Injury to the nerves in the arm, which may cause numbness, tingling, weakness, pain, and possible loss of movement

Immediate side effects usually occur around 10–14 days after starting radiation treatment, but can happen later in treatment or after it has finished.

The severity of your skin reactions depends on a few factors:

  • Dose of radiation given
  • Your skin type
  • Existing skin conditions, such as eczema, psoriasis, and so on

If you have existing skin conditions, let your radiation oncologist/doctor know before starting treatment because it may be useful for you to meet with a dermatologist (skin specialist) for advice.

Skincare during radiation therapy

You must take special care of your skin that is being treated with radiation. Your radiation oncologist or radiation technologist (who administers the radiation therapy treatments) will provide you with specific skincare instructions at the center. Most instructions will include the following actions and precautions:

  • Have a shower instead of a bath.
  • Wash the treated area gently with warm water using a mild soap and pat the skin dry with a soft towel.
  • Use a fragrance-free deodorant.
  • Use a mild moisturizer or recommended topical cream to keep skin soft.
  • If you want to use anything else on the skin in the treatment area, you must discuss this with your radiation doctor.
  • Avoid exposing the treated area to extremes of temperature such as heat pads, saunas, or ice packs during radiation treatment.
  • Avoid exposing the treated area to sun while having radiation and afterwards, until all skin changes at the treatment site have healed.
  • Avoid getting sunburn after treatment. Always use a sunscreen with a high sun protection factor (SPF) of 50 and above. You should also apply sunscreen under clothes because, thought it isn’t widely known, it is possible to contract sunburn through clothing.
  • Avoid swimming during treatment and afterwards until all skin reactions have healed. Chemicals in the swimming pool may cause skin irritation, and a swimsuit can cause friction and discomfort at the treatment site.
  • Wear a soft cotton bra or vest during treatments to avoid rubbing or friction that can worsen skin reactions.
  • Avoid wearing underwire bras until your skin is healed.

Your radiation technologist will monitor your skin during treatments. When a skin reaction develops, they will advise you on caring for your skin.

If you develop a skin reaction during radiation, it should heal within four weeks from the date of your last treatment. If your skin is taking longer than four weeks to heal, or you have severe blisters and skin peeling, you must contact your radiation treatment team or breast care nurse for advice.