[15] Hormonal Therapy Flashcards
What are hormones?
Substances produced naturally in the body which act as chemical messengers and influence the growth and activity of cells
What system does hormonal therapy aim to manipulate?
The endocrine system
How can the endocrine system be manipulated as part of cancer therapy?
- External administration of specific hormones
- Hormone antagonists
- Surgical removal of endocrine organs
What type of hormones are commonly externally administered as part of hormonal therapy?
Steroid hormones
How can drugs act as hormone antagonists?
- Inhibit hormone production
- Inhibit hormone activity
What endocrine organs can be removed as part of some hormonal therapy regimes?
- Orchiectomy
- Oophorectomy
How can changing the levels of certain steroid hormones lead to cancer cell death (or cessation of growth) in some cancers?
Steroid hormones are often powerful drivers of gene expression in certain cancer cells
What types of cancers are commonly treated with hormonal therapy?
Those derived from hormonal responsive tissues
What specific cancers are commonly treated with hormonal therapy?
- Breast
- Prostate
- Endometrium
- Adrenal cortex
What non-specific cancer complications can be treated with hormonal therapies?
- Paraneoplastic syndromes
- Chemotherapy-related symptoms e.g. anorexia
What are some types of hormone synthesis inhibitors used in hormonal cancer therapy?
- Aromatase inhibitors
- GnRH analogues
How doe inhibitors of hormone synthesis work to treat cancer?
They starve tumour cells of growth and survival-producing hormones by inhibiting their production
What type of cancer are aromatase inhibitors used to treat?
Breast cancer in post-menopausal women
What is the normal role of aromatase?
Produce oestrogen from androgens made by the adrenal glands in post-menopausal women
What is the effect of aromatase inhibitors in post-menopausal women?
Oestrogen levels drop to extremely low
Why are aromatase inhibitors not used in pre-menopausal women?
Oestrogen is still produced by the ovaries in pre-menopausal women so oestrogen levels won’t drop (ngl I’ve inferred this - it’s probably because it induces early menopause or something but it makes sense logically and helps me remember that they’re for post-menopausal women :) )
How can the drop in oestrogen caused by aromatase inhibitors treat breast cancer?
Extremely low oestrogen levels can cause growth arrest and/or apoptosis in hormone-responsive cancer cells
What are some examples of aromatase inhibitors?
- Anastrozole
- Letrozole
What do GnRH analogues aim to do in hormonal therapy?
Induce chemical castration
What is meant by chemical castration caused by GnRH analogues?
Complete suppression of production of oestrogen and progesterone in females and testosterone in males
How do GnRH analogues induce chemical castration?
Prolonged activation and subsequent desensitisation of pituitary gonadotrophs (cells that release LH and FSH) to natural GnRH
What is an example of a GnRH analogue used to treat cancer?
Goserelin
What is goserelin used to treat?
Hormone-responsive prostate cancer
How do hormone receptor antagonists work to treat cancer?
Bind to the normal receptor for a given hormone and prevent its action
What are some types of hormone receptor antagonists used to treat cancer?
- Selective-Oestrogen Receptor Modulators (SERMS)
- Anti-androgens
What is the action of SERMs
Act as antagonists of the oestrogen receptor
What are SERMs used to treat?
Treatment and chemo prevention of breast cancer
What is an example of a SERM used to treat breast cancer?
Tamoxifen
Who is tamoxifen used in to treat breast cancer?
Nearly all post-menopausal women with hormone receptor positive breast cancer
What is the mechanism of action of anti-androgens as a cancer therapy?
Bind and inhibit the androgen receptor, blocking the growth and survival-promoting effects of testosterone on certain prostate cancers
What are some examples of anti-androgens used as cancer therapy?
- Flumatide
- Bicalutamide
How can Hormone supplementation sometimes be used to treat cancer?
Some hormones can have a growth-inhibiting or cytotoxic effect on tumour cells
How can hormones cause growth-inhibition or death of tumour cells?
They can produce antagonism and feedback inhibition of the synthesis of other hormones
What are some examples of hormones that are supplemented as part of hormonal cancer therapy?
- Progesterones
- Androgens
- Oestrogens
- Somatostatin
What cancers ca progesterones be used to treat?
- Hormone responsive advanced breast cancer
- Hormone responsive endometrial cancer
- Hormone responsive prostate cancer
What cancers can androgens be used to treat?
Advanced breast cancer (rarely)
What cancers can oestrogens be used to treat?
Occasionally prostate cancer
How can oestrogens treat prostate cancer?
Suppress tesosterone production
What is the role of somatostatin in treating cancers?
- Suppression of hormonal syndromes which accompany pancreatic islet cell tumours
- Can suppress carcinoid syndrome
What is an example of a hormonal syndrome caused by an islet cell tumour of the pancreas?
Zollinger-Ellison syndrome in gastrinoma
What do the side effects of hormonal therapies depend on?
Type of therapy given
What are some potential side-effects of hormonal therapies?
- Tiredness
- GI problems
- Menopausal symptoms
- Hair thinning
- Muscle and bone problems
- Weight gain
- Headaches
- Cognitive impairment
- Mood swings and depression
- Thrombosis
What sort of GI problems may be caused by some hormonal therapies?
- Nausea
- Constipation and diarrhoea
- Anorexia
What muscle and bone problems can be caused by some hormonal therapies?
- Arthralgia
- Osteoprosis
