2.6 Radiation & Hormonal Therapy

2.6.1 What is Radiation Therapy?

Radiation therapy is a localized treatment that damages DNA within cancer cells to prevent them from multiplying and the cancer from growing (Canadian Breast Cancer Network [CBCN], 2022). This therapy can damage healthy cells, but those cells have the ability to repair themselves, whereas cancer cells do not.

You might receive this treatment type if you have had a mastectomy or breast-conserving surgery if you have cancer cells in your lymph nodes, or if you have stage IV breast cancer (CBCN, 2022).

For more information on radiation therapy, check out Mayo Clinic’s article below.

If you would like to learn more about radiation therapy, check out Video 10 (BC Cancer, 2021).

2.6.2 Preparing for Radiation

External beam radiation involves the use of high-energy X-rays to target and treat cancer cells in the area affected by cancer (CBCN, 2022). External tattoos and daily low-energy x-ray imaging are used to ensure accurate treatment positioning. It is important to know that radiation therapy is a painless treatment, meaning you will not feel or see anything while the radiation is going; however, you may hear a bit of a buzzing sound.

Before the treatment, your healthcare provider will ask what medications you are on (CBCN, 2022). Some medications can interfere with the effects of radiation and can even cause increased side effects.

Some medication types you will want to disclose are:

• prescription medications,
• over-the-counter medications,
• herbal medications,
• daily supplements,
• and natural health medications (CBCN, 2022).

Radiation treatments may vary from 5 to 28 days or more depending on the cancer type, grade, stage, and pathology (CBCN, 2022). This treatment usually takes only a couple of minutes, and then you can carry on with your activities of daily life.

2.6.3 Side Effects of Radiation

Side effects of radiation therapy can vary in intensity and duration depending on the person (CBCN, 2022).

Some side effects that occur in and around the radiation entry site include:

• redness,
• swelling,
• drying,
• itching,
• tightness,
• and sensitivity (Lymphedema Working Group, 2012).

Other side effects include fatigue, chest pain, and changes in breast shape or size (Lymphedema Working Group, 2012).

The side effects you experience depend on the radiation dose. Treatment regimes can be 5 (least common), 16, 25, or 28 fraction doses (BC Cancer, 2022d). It is important to note that radiation has a cumulative effect, meaning that you receive the same dose every day for a certain number of days. This effect means that it can take 10 days to 2 weeks or more before your body accumulates enough radiation to notice side effects of radiation

For more information about how to manage certain radiation therapy side effects, check out the article below.

2.6.4 Questions to Ask About Radiation Therapy

1. How long will I require radiation therapy?
2. If I had surgery (e.g., mastectomy or breast-conserving surgery), why do I need radiation therapy?
3. How successful is radiation therapy?
4. What are the side effects of radiation therapy?
5. Can I do anything to help decrease the side effects that I might experience?
6. Are all radiation therapies the same? If not, what radiation therapy am I receiving and why?
7. What should I do to prepare for my radiation therapy?
8. I have heard that radiation therapy can cause changes to my skin; is there anything that I can do to help lessen these changes?
9. Does radiation therapy cause scarring?
10. How long are the radiation therapy sessions? How long will I be receiving these treatments?
11. Am I able to continue to work while receiving radiation therapy? (Lymphedema Working Group, 2012)

2.6.5 What is Hormonal Therapy?

Hormonal therapy treats breast cancer that is hormone receptor-positive, which means your cancer cells have either progesterone or estrogen receptors (CBCN, 2022). This treatment involves changing hormone levels in your body or blocking the receptors from being stimulated.

There are a variety of uses for hormonal therapy, including:

• decreasing the chance of breast cancer recurrence,
• slowing the growth rate of metastasized breast cancer,
• and shrinking the tumour before surgery (CBCN, 2022).

2.6.6 Hormonal Therapy Drugs

Which hormonal therapy medications you will use depends on your breast cancer and what your healthcare team recommends (Canadian Cancer Society, n.d.z). The two main types of hormonal therapy drugs are estrogen receptor blockers and aromatase inhibitors.

As the name implies, estrogen receptor blockers, also known as estrogen receptor modulators (SERMs), inhibit your cancer cells from using estrogen to survive by blocking the receptors; these drugs do not influence your body’s overall estrogen levels (Canadian Cancer Society, n.d.z). SERMs can be administered either orally or by injection, depending on the specific drug.

SERM drugs include:

• tamoxifen (nolvadex, tomofen),
• evista (raloxifene),
• fareston (toremifene),
• and fulvestrant (faslodex) (Canadian Cancer Society, n.d.z; Lymphedema Working Group, 2012).

On the other hand, aromatase inhibitors are medications that affect the aromatase enzyme, which produces estrogen outside the ovaries in your body (Canadian Cancer Society, n.d.z). By preventing this enzyme from producing estrogen, the estrogen levels in your body will decrease, and your cancer cells will have less estrogen to use. Aromatase inhibitors only work for post-menopausal women as premenopausal women’s estrogen is mainly produced in the ovaries, which this drug does not affect.

Aromatase inhibitor drugs include:

• arimidex (anastroxole),
• aromasin (exemestane),
• and femara (letoxole) (Canadian Cancer Society, n.d.z; Lymphedema Working Group, 2012).

2.6.7 Ovarian Suppression & Ablation

Ovarian suppression and ablation are two treatments that prevent your ovaries from creating more estrogen (Canadian Cancer Society, n.d.z). Ovarian ablation involves inducing an irreversible menopause by either surgically removing your ovaries or using radiation therapy on them. Meanwhile, ovarian suppression causes temporary menopause by using medications over a long period of time (3 to 5 years). Some of these medications include goserelin, buserelin, and leuprolide.

2.6.8 Side Effects of Hormonal Therapy

Side effects of hormonal therapy vary based on the individual, specific medication, and duration of use (Canadian Cancer Society, n.d.z).

Some of the side effects you may experience include:

• nausea,
• diarrhea,
• hair loss or thinning,
• fertility issues,
• weight gain,
• vaginal discharge,
• sexual issues,
• and irregular menstruation (Canadian Cancer Society, n.d.z; Lymphedema Working Group, 2012).

If you would like to learn more about hormonal therapy, check out Video 11 (Canadian Cancer Society, 2023).

2.6.9 Questions to Ask About Hormonal Therapy

1. Is hormonal therapy more harmful than chemotherapy or radiation?
2. Will I receive other treatments alongside hormone therapy to treat my cancer?
3. Are there different types of hormonal therapy? What is the most effective type for my cancer?
4. Is this treatment risky? Are there a lot of side effects?
5. Are there any side effects that are long-term or permanent?
6. How long will I require hormonal therapy?
7. Do I have to go to a clinic or hospital to receive treatment?
8. How will I know if this treatment is working?
9. Can I carry out my normal day-to-day activities while receiving hormone therapy? (Lymphedema Working Group, 2012)