Hormone (endocrine) therapy, which is used especially in breast, prostate cancer and uterine cancer, can slow down or stop the growth of hormone-fed tumors. Endocrine treatments, which differ from each other according to cancer types, have advantages such as preventing cancer from coming back and reducing the size of the tumor before surgery. Endocrine therapy, added to other cancer treatments, can often also be used to relieve cancer symptoms.
What is Hormone (Endocrine) Therapy in Cancer?
Hormone therapy is a treatment that uses hormones to slow or stop the growth of cancer. This treatment process is applied to treat some cancers such as prostate, breast cancer that use hormones to grow, hormone therapy is also called endocrine therapy.
In Which Cancer Types Is Hormone Therapy Used?
Endocrine treatments acting on hormones are applied in breast cancer, prostate cancer, neuroendocrine tumors and some gynecological cancers. Hormone therapy is performed in breast, prostate, neuroendocrine and uterine cancers, and hormone treatments applied in these cancer types differ from each other according to the cancer types.
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1-Hormone Treatments in Breast Cancer
The female hormones estrogen and progesterone affect some breast cancers. they are referred to as estrogen receptor positive (ER+) or progesterone receptor positive (PR+), or both. Hormone therapy for breast cancer blocks these hormones from reaching breast cancer cells.
There is more than one hormone therapy available to treat breast cancer. Drugs used in hormone therapy can be examined in 4 classes:
Selective estrogen receptor modifier: Tamoxifen
Tamoxifen works by blocking estrogen receptors, and estrogen inhibits the growth of cancer cells. Tamoxifen is one of the most common hormone treatments for breast cancer. Tamoxifen can be used by women who are currently menstruating (pre-menopausal) and menopausal (post-menopausal).
Hormone therapy (tamoxifen or raloxifene) may be recommended for those at high risk of breast cancer, this is called chemoprevention, but it is not suitable for every patient.
LHRH agonists for ovarian suppression: goserelin, leuprolide (leuprolide)
Reversible suppression of ovarian function using LHRH agonists is the first line of treatment of choice for most premenopausal breast cancer patients.
Selective estrogen downregulator: fulvestrant
Selective estrogen receptor reducer (SERD) is a type of drug that binds to the estrogen receptor (ER) and in doing so causes the estrogen receptor to malfunction. Selective estrogen receptor modulators are used to treat estrogen receptor sensitive or progesterone receptor sensitive breast cancer.
Aromatase inhibitors: anastrozole, letrozole, exemestane
Aromatase inhibitors stop postmenopausal estrogen production in women. Aromatase inhibitors work by blocking the enzyme aromatase, which converts the androgen hormone into small amounts of estrogen in the body. This means that less estrogen is available to stimulate the growth of hormone receptor-positive breast cancer cells.
2-Hormone Treatments in Prostate Cancer
In prostate cancer, hormone treatments that reduce androgen levels are performed:
Treatments that reduce androgen levels
Orchiectomy (surgical castration): The testicles are the most important source of androgens. In this surgical procedure, the patient’s testicles are surgically removed. This method is surgical hormone therapy, it is simple and inexpensive.
LHRH agonists: LHRH agonists reduce testosterone production in the testicles. This treatment with drugs is sometimes called chemical castration or medical castration because it reduces androgen levels as effectively as orchidectomy (surgical castration). LHRH agonists are usually given as a monthly or quarterly injection.
LHRH antagonists: Degarelix (Firmagon) is an LHRH antagonist that lowers testosterone levels faster and does not cause flare effects. It is applied in the treatment of advanced prostate cancer and is used as a monthly subcutaneous injection.
CYP17 suppressor: LHRH agonists and antagonists work to inhibit androgen production in the testicles. however, if prostate cancer has spread throughout the body, these cells still continue to produce androgens, which trigger cancer growth, albeit to a small extent. The drug called abiraterone blocks the enzyme CYP17, thus blocking androgen production not only in the testicles, but also in the adrenal glands or prostate cancer cells that have spread (metastasized) throughout the body. Abiraterone is a daily pill and is used to treat advanced hormone therapy-resistant prostate cancer. Enzalutamide shows its effect by preventing the binding of male hormones (androgens) such as testosterone and dihydrotestosterone to the androgen receptors in the prostate cancer cell. It is one of the new generation hormone suppression treatments.
- Anti-androgens: Prevents androgens from binding to testosterone receptors.
- Next generation testosterone receptor blockers: When androgens bind to its receptor, the receptor sends a growth and division signal, and enzalutamide blocks this signal.
3-Hormone Treatments in Neuroendocrine Tumors
Treatment with somatostatin analogs in neuroendocrine tumors.
Somatostatin analogs create synthetic versions of the hormone somatostatin. These drugs can suppress tumor growth in somatostatin receptor positive patients and control symptoms caused by hormones secreted by tumors. In addition, it slows down or stops the development of the tumor in metastatic neuroendocrine cancers.
Somatostatin analogs used in the treatment of carcinoid tumors
The drugs used in the treatment may contribute to the prolongation of the patient’s life expectancy by slowing or stopping the development of the spreading carcinoid tumor. It can also treat symptoms such as wheezing, rash, and nausea. In addition, octreoid is sometimes used for the prevention and treatment of problems caused by secreted serotonin or other hormones when surgery is performed on patients with carcinoid tumors.
4-Hormone Treatments in Uterine Cancer
Hormone therapy is used to slow the growth of certain types of uterine cancer cells. These tumors are usually adenocarcinomas and are usually grade 1 or 2. Hormone therapy can be considered in patients with uterine tumor grade 1 or 2 and positive female hormone receptors who cannot receive chemotherapy. The rate of benefit from treatment with these drugs is between 15-30%.
Drugs that act by suppressing the aromatase enzyme, such as letrozole and anastrazole, which are other hormone-suppressing treatment options, are less effective in uterine cancer. In studies, the rate of benefit from treatment is less than 10%. Hormone therapy for uterine cancer is usually given in pill form.
What are the Advantages of Hormone Therapy in Cancer?
- Prevents cancer from coming back
- Reduces the risk of developing cancer in other breast tissue
- Slows or stops the growth of cancer that has spread
- Reduces the size of a tumor before surgery
What are the Side Effects of Hormone Therapy?
Hormone therapy can cause unwanted side effects because it inhibits the body’s ability to produce hormones or interferes with how hormones behave. The side effects that occur depend on the type of hormone therapy taken and how the body responds to it. Each patient may react differently to the same treatment, so not everyone experiences the same side effects. It is possible that some side effects may differ depending on gender.
Some common side effects that can occur in men receiving hormone therapy for prostate cancer include:
- Hot Flashes
- Sexual reluctance and loss of sexual function
- Weakening of bones
- Diarrhea
- Nausea
- Enlarged and tender breasts
- Fatigue
Some common side effects that can occur in women receiving hormone therapy for breast cancer include:
- Hot flashes
- Vaginal dryness
- Changes in menstrual periods in non-menopausal women
- Loss of sexual desire
- Nausea
- Mood changes
- Fatigue
Some common side effects that can occur in women receiving hormone therapy for uterine cancer include:
- Water retention
- Weight gain (due to water retention)
- Breast discomfort
- Fatigue
- Feeling sick
- Loss of sexual drive
Frequently asked Questions
According to the pathological features, breast cancers are roughly divided into 4 groups; hormone positive (Luminal A/B), HER 2 positive and triple negative. Among these types, endocrine treatments are applied only to the patients in the hormone positive group.
These treatments are performed in both the early and metastatic stages of breast cancer. The duration of treatment in the early stage is determined according to the patient’s risk factors and menopause status. In the metastatic stage, as long as the patient benefits from the treatment and there are no serious side effects, the treatment is continued indefinitely. In case of disease progression under treatment, a different endocrine therapy can be used. or in cases where endocrine resistance develops, this treatment is continued by adding drugs with resistance breaking effect.
Hormone therapy in cancer falls into two broad groups: those that inhibit the body’s ability to produce hormones and those that interfere with how hormones behave in the body.
Hormone therapy is used to treat prostate, breast, uterine, and neuroendocrine cancers that use hormones to grow. It is often used in combination with other cancer treatments. The types of treatment needed depend on the type of cancer, whether and how far it has spread, whether it is using hormones to grow, and whether there are other health problems.
Hormone therapy is often used in combination with other treatments. The timing varies depending on the stage and location of the tumor, among other factors.
Hormone therapy is used in conjunction with other cancer treatments such as surgery, chemotherapy, and radiotherapy. and when used with other cancer treatments, it has the following effects:
- It is used to shrink a tumor before surgery or radiation treatment. It is called neoadjuvant therapy.
- It reduces the risk of the cancer coming back after the main treatment. It is called adjuvant therapy.
- It removes cancer cells that have returned or spread to other parts of the body.
Test and imaging methods are used to follow the tumor. Men with prostate cancer have regular blood tests called prostate-specific antigen (PSA) tests to measure their hormones. Prostate MRI is also used to monitor prostate cancer.
Targeted therapy drugs can attack certain weaknesses in cancer cells, making combination hormone therapy more effective.
Hormone receptor tests measure the proportion of certain proteins (also known as hormone receptors) in cancer cells. Hormones produced naturally in the body (such as estrogen and progesterone) can bind to these proteins in cancer cells, helping them grow. If the test is positive, the hormone is probably helping the cancer cells grow, and hormone therapy may help in this case. If the test is negative, the hormone does not affect the growth of cancer cells, instead other cancer treatments are applied.
Hormone therapy for prostate cancer can cause weight gain, and help from a dietitian should be sought in order to maintain the ideal weight.
Hormone therapy does not affect the ability to work, patients receiving this therapy can continue their work life.
It is possible for prostate cancer and its treatment to affect sexual desire. In prostate cancer, hormone therapy lowers the sex drive because some types of hormone therapy lower testosterone levels. After hormone therapy is stopped, sexual desire may increase, but this may take several months.
Castration-resistant prostate cancer (CRPC) is considered disease progression despite androgen-lowering therapy. this results in a sustained increase in serum prostate-specific antigen (PSA) levels, progression of pre-existing disease, and/or formation of new metastases.
In women on hormonal drug therapy, treatment-induced menopause may be temporary, while for some women, treatment-induced menopause may be permanent, especially in women who are close to natural menopause when hormonal drug therapy is started, or in women whose ovaries have been surgically removed or whose ovaries have undergone radiation therapy.
Fertility problems may be temporary or permanent in cancer patients receiving hormone therapy. A permanent loss of fertility (infertility) can result from surgical removal of the testicles or ovaries. In addition, hormone and radiation therapy can also cause temporary or permanent infertility.
