ENDOCRINE THERAPY
Endocrine or hormonal therapy is used as adjuvant therapy to treat micrometastases before they are clinically detectable in patients with high risk of metastatic recurrence of the disease.
Many cancer cells have oestrogen receptors which can influence the aggressiveness of the cancer. The sensitivity of a tissue to a hormone depends on the hormone receptors which can specifically bind the hormone on the cell membrane or inside the cell (steroid hormones). When a hormone binds with the receptor the cell’s growth is stimulated and therefore the cancer continues to grow. The oestrogen receptor status of a patient’s cancer can be determined by histochemical or biochemichal methods and if the receptors are more than 10Fmol/mg (femptomoles per milligram) then the cancer is termed ER+.
Patients with ER+ tumours have a better response to the endocrine therapy and therefor a higher survival rate and a lower recurrence rate. Unfortunately cancers are comprised by both ER+ and ER- cells. This means that the cells that are not sensitive to hormones will not be affected by the hormone therapy and therefore will continue to grow, in which case multiple endocrine therapies differed hormones can be used to attack those cells.
Endocrine therapy can be given before surgery to shrink the tumour similarly to chemotherapy and after the surgical removal of the tumour to block oestrogen production, down-regulate the production of oestrogen from targeting the pituitary gland or blockthe oestrogen receptors of the cells.
The oestrogen production can be blocked by ovarian ablation. The ovarian ablation can be achieved by the surgical removal of the ovaries, radiotherapy delivered electricity to the pelvis fro menopausal women, injections of Zaladex or administration of aromatace inhibitors.
Zoladex blocks the hormone production in the anterior pituitary gland that stimulates the oestrogen production from the ovaries. Side effects of this drug may cause menopausal symptoms such as hot flushes and sweets, lethargy, nausea, indigestion and weight gain.
Aromatace inhibitors are given to postmenopausal women whose adrenal glands are still producing oestrogen. Those drugs block the production of oestrogen from the adrenal glands
Down-regulation of the pituitary gland can be achieved by increasing the blood levels of another hormone produced in the ovaries to ‘fool’ the pituitary gland into thinking that the ovaries are over-producing hormones and switch of the hormonal stimulation of the ovaries. In secondary breast tumours progesterone is usually used. Side effects include nausea, muscle cramps, rashes, fatigue, tenderness of the breasts, loss of appetite and insomnia.
Oestrogen receptors of the cells are blocked using Tamoxifen, which is a receptor antagonist that binds onto and blocks the oestrogen receptors and therefore can block the oestrogen stimulation of the cancer cells. Tamoxifen is usually used in postmenopausal women with invasive cancer but in some cases it is administered to premenopausal women with ER+ tumours after the chemotherapy treatment. Side effects include hot flushes, menstrual problems, vaginal irritation and discharge, fluid retention, depression, rashes, weight gain and ophthalmic problems. The dtug can also bring on menopause in women who are close to that age.
Similarly to chemotherapy endocrine therapy can be used for women with advanced metastatic cancer to slow down the progression of the disease or as primary therapy in elderly women who are unfit or unwilling to have surgery.
Endocrine or hormonal therapy is used as adjuvant therapy to treat micrometastases before they are clinically detectable in patients with high risk of metastatic recurrence of the disease.
Many cancer cells have oestrogen receptors which can influence the aggressiveness of the cancer. The sensitivity of a tissue to a hormone depends on the hormone receptors which can specifically bind the hormone on the cell membrane or inside the cell (steroid hormones). When a hormone binds with the receptor the cell’s growth is stimulated and therefore the cancer continues to grow. The oestrogen receptor status of a patient’s cancer can be determined by histochemical or biochemichal methods and if the receptors are more than 10Fmol/mg (femptomoles per milligram) then the cancer is termed ER+.
Patients with ER+ tumours have a better response to the endocrine therapy and therefor a higher survival rate and a lower recurrence rate. Unfortunately cancers are comprised by both ER+ and ER- cells. This means that the cells that are not sensitive to hormones will not be affected by the hormone therapy and therefore will continue to grow, in which case multiple endocrine therapies differed hormones can be used to attack those cells.
Endocrine therapy can be given before surgery to shrink the tumour similarly to chemotherapy and after the surgical removal of the tumour to block oestrogen production, down-regulate the production of oestrogen from targeting the pituitary gland or blockthe oestrogen receptors of the cells.
The oestrogen production can be blocked by ovarian ablation. The ovarian ablation can be achieved by the surgical removal of the ovaries, radiotherapy delivered electricity to the pelvis fro menopausal women, injections of Zaladex or administration of aromatace inhibitors.
Zoladex blocks the hormone production in the anterior pituitary gland that stimulates the oestrogen production from the ovaries. Side effects of this drug may cause menopausal symptoms such as hot flushes and sweets, lethargy, nausea, indigestion and weight gain.
Aromatace inhibitors are given to postmenopausal women whose adrenal glands are still producing oestrogen. Those drugs block the production of oestrogen from the adrenal glands
Down-regulation of the pituitary gland can be achieved by increasing the blood levels of another hormone produced in the ovaries to ‘fool’ the pituitary gland into thinking that the ovaries are over-producing hormones and switch of the hormonal stimulation of the ovaries. In secondary breast tumours progesterone is usually used. Side effects include nausea, muscle cramps, rashes, fatigue, tenderness of the breasts, loss of appetite and insomnia.
Oestrogen receptors of the cells are blocked using Tamoxifen, which is a receptor antagonist that binds onto and blocks the oestrogen receptors and therefore can block the oestrogen stimulation of the cancer cells. Tamoxifen is usually used in postmenopausal women with invasive cancer but in some cases it is administered to premenopausal women with ER+ tumours after the chemotherapy treatment. Side effects include hot flushes, menstrual problems, vaginal irritation and discharge, fluid retention, depression, rashes, weight gain and ophthalmic problems. The dtug can also bring on menopause in women who are close to that age.
Similarly to chemotherapy endocrine therapy can be used for women with advanced metastatic cancer to slow down the progression of the disease or as primary therapy in elderly women who are unfit or unwilling to have surgery.