Hormone therapy

What is it ?

Hormone therapy is one of the tools in the therapeutic arsenal against cancer.

Its role is crucial in the treatment and prevention of recurrences in hormone-sensitive cancers: breast cancer, endometrial (or uterine body) cancer, and prostate cancer.

How it works ?

The term hormone therapy is somewhat misnomer. In fact, the aim of these therapies is to prevent hormonal stimulation of cancer cells through various means. Therefore, they are more accurately described as 'anti-hormone' therapies.

Breast cancer

80% of breast cancers express estrogen and/or progesterone receptors on the surface of their cells. When these hormones attach to the surface of tumor cells, they stimulate their proliferation.

There are 3 types of hormone therapies for breast cancer :

• Anti-estrogens, which either block estrogen from binding to the hormonal receptors on tumor cells or degrade these receptors
• LH-RH analogs, which suppress the production of female hormones by the ovaries in premenopausal women
• Aromatase inhibitors, which prevent the production of estrogen in menopausal women.

Prostate cancer

The development of prostate cancer is related to androgen metabolism, particularly through the fixation of testosterone to the androgen receptor present in tumor cells.

For prostate cancers initially sensitive to hormone therapy, this is referred to as castration sensitivity. The prescribed molecules are LH-RH agonists or LH-RH antagonists.

These medications are primarily administered via injection (subcutaneously) on a monthly, quarterly, or even semi-annual basis. This treatment can also be supplemented with oral medications.

When the cancer is initially metastatic or becomes resistant to castration, “next-generation hormone therapies” may be prescribed. These come in oral form and are used in conjunction with injectable hormone therapy that the patient will need to continue.

The testosterone level in the blood (which should be very low) helps measure adherence, while the PSA level measures the effectiveness of the treatment.

Endometrial cancer

Just like in breast and prostate cancer, endometrial tissue develops under the influence of female hormones. This hormonal influence regulates menstrual cycles in physiological conditions.

When a cell transforms into a cancer cell, it may retain sensitivity to estrogen and progesterone through the presence of hormone receptors on its surface. To slow down tumor growth, hormone therapy can be used.

Another form of hormone therapy is possible but less commonly used: surgery (bilateral oophorectomy in women, bilateral orchiectomy in men).

Catherine, 53, shares her experience with her battle against breast cancer and her treatment with hormone therapy.

Side effects

The frequency and intensity of side effects can vary greatly from one patient to another. There are solutions available to manage these adverse effects.

It is therefore essential to discuss your symptoms with your oncologist, as proper adherence to the treatment is crucial for controlling the cancer.

Adverse effects of hormone therapies include :

• Osteoporosis: a measurement of bone mineral density through bone densitometry will be prescribed at the start of and during the treatment.
• Increased cardiovascular risk requiring regular specialized monitoring, especially if pre-existing risk factors are present.
• Weight gain
• Sexual issues: decreased libido, erectile dysfunction in men
• Hot flashes
• Irritability
• Breast pain
• Decreased size of the penis and testicles in men?
• Risk of deep vein thrombosis (phlebitis) for medications targeting estrogen

Indications

In breast cancer

In breat cancer, hormone therapy can be used at all stages of the disease. At the localized stage: it is prescribed after radical treatment for a duration of 5 years or more in some cases.

At the metastatic stage: Alone or in combination with other systemic treatments, it can slow down or even halt the spread of the cancer.

In endometrial cancer

In endometrial cancer, hormone therapy is indicated in metastatic stages. It can be prescribed alone for indolent (slow-growing) forms or for patients who are too frail to tolerate chemotherapy.

In prostate cancer

In prostate cancer, hormone therapy is the cornerstone of treatment. Once started, it must be continued for life, even in cases of castration resistance, as it still has an effect at this stage.

At the localized stage, hormone therapy is prescribed for cancers at intermediate and high risk of recurrence. The duration is adjusted based on the risk, most often between 6 months and 3 years.

At the metastatic stage or in cases of secondary castration resistance, hormonal treatment should be continued, and your oncologist may decide to add a so-called "next-generation" oral hormone therapy or chemotherapy.