Zoladex and Stopping the Ovaries
The ovaries, oestrogen and breast cancer
Many breast cancers are dependent for their growth on the presence of the female sex hormone, oestrogen, in the circulating blood. Just as bursts of oestrogen cause proliferation of duct tissue in the breast with each menstrual cycle, breast cancer cells also respond to it with growth.
Only breast cancer cells that express the hormone receptors, the oestrogen or progesterone receptor, are sensitive to the growth-stimulatory effects of oestrogen. About 70% of breast cancers are hormone sensitive. Breast cancers that are negative for the oestrogen and progesterone receptors do not respond to hormonal manipulation.
The main source of oestrogen in women who have not been through the menopause is the ovary, a small gland that sits at the back of the pelvis on either side of the top of the uterus (womb). The ovaries produce mature eggs with each menstrual cycle, but they are also an engine-room for the production of oestrogen and progesterone. Oestrogen levels in the blood are about 10-times higher in pre-menopausal women compared to women who have been through menopause. After menopause, oestrogen is mainly produced in the adrenal glands and the fat tissue of the body, but at much lower levels than those produced from the pre-menopausal ovaries.
If we want to starve breast cancer cells of oestrogen the easiest way in pre-menopausal women is to shut off the main supply – that is the ovaries. The simplest way of doing this is to remove the ovaries.
Removing the ovaries: “Oophorectomy”
This is the oldest way of shutting off oestrogen production in pre-menopausal women. It is still one of the most effective. It is performed nowadays by a simple “key-hole” (“laparoscopic”) procedure through a single small incision in the lower abdominal wall, below the bikini line. It is a day-only procedure, which is performed under a light general anaesthetic. Most women have few problems afterwards, apart from some mild pelvic discomfort, like period pain, the day after. Women who have the procedure on a Friday are usually OK to go to work on the following Monday.
Occasionally oophorectomy is performed by a larger formal open operation, often with removal of the uterus (womb) at the same time. This is usually only done if there is some reason to remove the uterus, such as abnormal bleeding or fibroids.
Why don’t we routinely remove the uterus?
The reason is that this is a larger operation with more side-effects. Whilst generally safe, we prefer not to do a slightly more risky operation if there is no indication. Key-hole removal of the ovaries is extremely safe.
The advantages of oophorectomy are:
The disadvantages of oophorectomy are:
Special Note:
You still need to have regular Pap tests if you have had your ovaries removed. Only women who have had a total hysterectomy, in which the cervix is removed, are free of the need for regular Pap tests. Pap tests should be performed second yearly, or annually for women taking tamoxifen.
As of December 1, 2017 the Cervical Screening Test has replaced the 2 yearly Pap test. The Cervical Screening Test is performed once every 5 years if your results are normal.
Zoladex (“goserelin”)
Zoladex is a hormonal substance that is injected in depot form under the skin of the lower abdomen once per month. The hormone acts on the pituitary gland to prevent the secretion of a signal from that gland that is necessary to stimulate ovarian oestrogen production. Without this stimulus from the pituitary gland, the ovaries produce no oestrogen. Some people call this a “medical menopause”. As a consequence of this injection, all the effects of menopause will be experienced: the menstrual periods will cease (usually immediately, although some women will experience one period after their first depot injection.)
How long do I take it for?
For women having Zoladex as adjuvant treatment after early breast cancer the duration of treatment is generally monthly for two years.
When should I start it?
Generally we advise starting your first injection in the first 10 days following a normal period. For women with very irregular periods this may not be possible.
If being used as adjuvant treatment for early breast cancer, the Zoladex is usually started after all chemotherapy and radiotherapy has been completed. This is because hormonal manipulation may interfere with the effectiveness of chemotherapy and radiotherapy, and clinical trials have shown that this is the best sequence.
For women having Zoladex as treatment for advanced or metastatic breast cancer the duration of treatment will vary from person to person and you need to seek the advice of your oncologist.
What is the normal dose?
The normal dose is 3.6 mg monthly by depot injection. The injection is usually given by your GP. There is a larger three-monthly depot injection available, but it is only on the PBS for men with prostate cancer for reasons that are beyond me.
Advantages of Zoladex:
Disadvantages of Zoladex:
A compromise: Zoladex followed by ovarian removal.
There is a useful compromise for women who don’t want to face the extended cost of Zoladex, yet who want to “see what menopause is like” before committing to the finality of ovarian removal. This is to take Zoladex for several months and then move on to ovarian removal when they feel comfortable about it. This also has the advantage of possibly bringing on a more “gentle” onset of the menopause.
What are menopausal symptoms and how do I manage them?
For full advice on this, click here.
I have been on Zoladex for two years? Should I continue longer?
For women who are having Zoladex as adjuvant therapy for early breast cancer we don’t know the answer to this question, as there are as yet no data from clinical trials. The experts at the St Gallen Breast Cancer Conference (January 2005) were asked their opinions. There was no real consensus. 57% voted for, and 21% against 2-3 years. 28% voted for 5 years, while 64% voted against that longer duration. I think if we follow the trials so far, 2-3 years is probably going to be optimal.
My advice: ask your oncologist, of course, but if you are tolerating it well, can afford it, and you had a higher-risk early breast cancer, I would probably stay on it for 3 years.
Zoladex and Fertility Preservation - results from the POEMS study
A study published in 2015 (The POEMS study) showed that premenopausal women diagnosed with hormone-receptor-negative, early-stage breast cancer who were treated with Zoladex (chemical name: goserelin) along with chemotherapy after surgery were much less likely to be infertile after chemotherapy ended than women who got chemotherapy without Zoladex. More women who received Zoldadex with their chemotherapy had babies post chemotherapy, in comparison to those who had chemotherapy alone. These women commenced Zoladex one week prior to the start of their chemotherapy and continued it until either 2 weeks before or after the final chemotherapy dose. You can read the article here.
Unfortunately if you have an ER positive breast cancer the study does not apply to you, however it may be worth a discussion with me at your first appointment.
Zoladex is unfortunately not currently reimbursed on the PBS for women with ER negative breast cancer. It will cost you approximately $330 / month.
Many breast cancers are dependent for their growth on the presence of the female sex hormone, oestrogen, in the circulating blood. Just as bursts of oestrogen cause proliferation of duct tissue in the breast with each menstrual cycle, breast cancer cells also respond to it with growth.
Only breast cancer cells that express the hormone receptors, the oestrogen or progesterone receptor, are sensitive to the growth-stimulatory effects of oestrogen. About 70% of breast cancers are hormone sensitive. Breast cancers that are negative for the oestrogen and progesterone receptors do not respond to hormonal manipulation.
The main source of oestrogen in women who have not been through the menopause is the ovary, a small gland that sits at the back of the pelvis on either side of the top of the uterus (womb). The ovaries produce mature eggs with each menstrual cycle, but they are also an engine-room for the production of oestrogen and progesterone. Oestrogen levels in the blood are about 10-times higher in pre-menopausal women compared to women who have been through menopause. After menopause, oestrogen is mainly produced in the adrenal glands and the fat tissue of the body, but at much lower levels than those produced from the pre-menopausal ovaries.
If we want to starve breast cancer cells of oestrogen the easiest way in pre-menopausal women is to shut off the main supply – that is the ovaries. The simplest way of doing this is to remove the ovaries.
Removing the ovaries: “Oophorectomy”
This is the oldest way of shutting off oestrogen production in pre-menopausal women. It is still one of the most effective. It is performed nowadays by a simple “key-hole” (“laparoscopic”) procedure through a single small incision in the lower abdominal wall, below the bikini line. It is a day-only procedure, which is performed under a light general anaesthetic. Most women have few problems afterwards, apart from some mild pelvic discomfort, like period pain, the day after. Women who have the procedure on a Friday are usually OK to go to work on the following Monday.
Occasionally oophorectomy is performed by a larger formal open operation, often with removal of the uterus (womb) at the same time. This is usually only done if there is some reason to remove the uterus, such as abnormal bleeding or fibroids.
Why don’t we routinely remove the uterus?
The reason is that this is a larger operation with more side-effects. Whilst generally safe, we prefer not to do a slightly more risky operation if there is no indication. Key-hole removal of the ovaries is extremely safe.
The advantages of oophorectomy are:
- Simplicity. It is all over in one day with no need for repeated injections.
- Reducing the risk of ovarian cancer. Cancer of the ovary is rare, but slightly increased in women with who have had breast cancer, and substantially increased in women with a strong family history of breast/ovarian cancer.
The disadvantages of oophorectomy are:
- Permanence. The menopause induced by oophorectomy is permanent and non-reversible. This is an important issue for young woman who may still be planning a family.
- Rapid onset of menopausal symptoms. If menopausal symptoms are to occur they may occur more rapidly after oophorectomy, whereas the use of Zoladex tends to induce a more gentle menopause.
Special Note:
You still need to have regular Pap tests if you have had your ovaries removed. Only women who have had a total hysterectomy, in which the cervix is removed, are free of the need for regular Pap tests. Pap tests should be performed second yearly, or annually for women taking tamoxifen.
As of December 1, 2017 the Cervical Screening Test has replaced the 2 yearly Pap test. The Cervical Screening Test is performed once every 5 years if your results are normal.
Zoladex (“goserelin”)
Zoladex is a hormonal substance that is injected in depot form under the skin of the lower abdomen once per month. The hormone acts on the pituitary gland to prevent the secretion of a signal from that gland that is necessary to stimulate ovarian oestrogen production. Without this stimulus from the pituitary gland, the ovaries produce no oestrogen. Some people call this a “medical menopause”. As a consequence of this injection, all the effects of menopause will be experienced: the menstrual periods will cease (usually immediately, although some women will experience one period after their first depot injection.)
How long do I take it for?
For women having Zoladex as adjuvant treatment after early breast cancer the duration of treatment is generally monthly for two years.
When should I start it?
Generally we advise starting your first injection in the first 10 days following a normal period. For women with very irregular periods this may not be possible.
If being used as adjuvant treatment for early breast cancer, the Zoladex is usually started after all chemotherapy and radiotherapy has been completed. This is because hormonal manipulation may interfere with the effectiveness of chemotherapy and radiotherapy, and clinical trials have shown that this is the best sequence.
For women having Zoladex as treatment for advanced or metastatic breast cancer the duration of treatment will vary from person to person and you need to seek the advice of your oncologist.
What is the normal dose?
The normal dose is 3.6 mg monthly by depot injection. The injection is usually given by your GP. There is a larger three-monthly depot injection available, but it is only on the PBS for men with prostate cancer for reasons that are beyond me.
Advantages of Zoladex:
- Reversibility. The effects of Zoladex are reversible. If you decide for some reason that you wish to stop the Zoladex, for example, because of intolerable menopausal symptoms, then your periods will generally return within three months of ceasing the depot injections. Remember that all women go through menopause normally around the age of 50, and some do so even ten years earlier. This is set by the “biological clock” in your body, and Zoladex will not alter that “clock”. If, say, you are on the Zoladex for several years, and your body reached its predetermined menopause time during those years of Zoladex treatment, then your periods may not return when you cease the Zoladex. We have no way of knowing when your “biological” menopause will be.
Disadvantages of Zoladex:
- Inconvenience. You have to attend for your monthly injections without fail. They don’t have to be precisely on the same day of each month, but within a week is OK.
- Cost. Zoladex is only on the PBS in Australia for pre-menopausal women who have breast cancer which has positive hormone receptors. The cost is around $AU330.00 per month.
A compromise: Zoladex followed by ovarian removal.
There is a useful compromise for women who don’t want to face the extended cost of Zoladex, yet who want to “see what menopause is like” before committing to the finality of ovarian removal. This is to take Zoladex for several months and then move on to ovarian removal when they feel comfortable about it. This also has the advantage of possibly bringing on a more “gentle” onset of the menopause.
What are menopausal symptoms and how do I manage them?
For full advice on this, click here.
I have been on Zoladex for two years? Should I continue longer?
For women who are having Zoladex as adjuvant therapy for early breast cancer we don’t know the answer to this question, as there are as yet no data from clinical trials. The experts at the St Gallen Breast Cancer Conference (January 2005) were asked their opinions. There was no real consensus. 57% voted for, and 21% against 2-3 years. 28% voted for 5 years, while 64% voted against that longer duration. I think if we follow the trials so far, 2-3 years is probably going to be optimal.
My advice: ask your oncologist, of course, but if you are tolerating it well, can afford it, and you had a higher-risk early breast cancer, I would probably stay on it for 3 years.
Zoladex and Fertility Preservation - results from the POEMS study
A study published in 2015 (The POEMS study) showed that premenopausal women diagnosed with hormone-receptor-negative, early-stage breast cancer who were treated with Zoladex (chemical name: goserelin) along with chemotherapy after surgery were much less likely to be infertile after chemotherapy ended than women who got chemotherapy without Zoladex. More women who received Zoldadex with their chemotherapy had babies post chemotherapy, in comparison to those who had chemotherapy alone. These women commenced Zoladex one week prior to the start of their chemotherapy and continued it until either 2 weeks before or after the final chemotherapy dose. You can read the article here.
Unfortunately if you have an ER positive breast cancer the study does not apply to you, however it may be worth a discussion with me at your first appointment.
Zoladex is unfortunately not currently reimbursed on the PBS for women with ER negative breast cancer. It will cost you approximately $330 / month.