Case 14- Anticancer drugs Flashcards
Adjuvant chemotherapy
After theoretical surgical cure to increase the chance of cure, reduces the risk of relapse, killing any microscopic disease left behind.
Neo-adjuvant chemotherapy
Before the surgery to improve operability and chances of cure i.e. to shrink the tumour prior to removal
Palliative chemotherapy
Used for symptom control not cure, advanced cancer
Difference between targeted and non-targeted chemotherapy
Chemotherapy can be broadly divided into targeted and non-targeted. Non-targeted chemotherapy agents block the stages of the cell cycle, inhibiting DNA replication and mitosis. Targeted chemotherapy can differentiate between cancerous and non-cancerous cells.
Types of non-targeted anicancerous agents
Alkylating agents, Platinum agents, Antimetabolites, Anthracyclines, Anti-microtubule agents.
Cancer- Alkylating agents
For example, Cyclophosphamide. Covalently bind to Alkyl groups in the nucleotide Guanine, induces crosslinking DNA. The inhibits DNA replication and transcription so the cell undergoes cell cycle arrest and apoptosis.
Examples of Alkylating agents (cancer)
- Cyclophosphamide-leukaemias, lymphoma and solid tumours
* Chlorambucil-lymphoma and chronic leukaemias
Cancer- Platinum agents
For example, Cisplatin. Most widely used chemotherapy drugs. They bind to the nucleotide Guanine causing cross linked DNA which inhibits DNA replication and transcription. The cell undergoes cell cycle arrest and apoptosis. Connected to the Platinum you have two highly reactive Chlorine groups which interact with other proteins responsible for replication. They cause DNA protein cross links, induces stress mechanisms within the cells and the cells undergo apoptosis.
Examples of Platinum agents
- Carboplatin- ovarian and lung cancer
* Cisplatin- testicular, lung, cervical, bladder and head/neck cancer
Cancer- Antimetabolites
For example Methotrexate. They interfere with the normal cell metabolism of nucleic acids. Methotrexate inhibits the production of Pyrimidines and Purines by inhibiting the enzyme DHFR. Decreases nucleotides inhibiting DNA replication
Normal production of Purines and Pyrimidines
Dietary folate is converted to FH2 which is converted by DHFR (Dihydrofolate reductase) into FH4. This is then converted to Purines or can be converted to Pyrimidines by Thymidylate synthase.
Example of antimetabolites
- Methotrexate-acute leukaemia, non-Hodgkin’s lymphoma and solid tumours
- 5-Fluorouracil- GI and breast cancer
Anthracyclines
For example Doxorubicin. These are anti-tumour antibiotics.
1) Inhibits Tropoisomerase 2 (Its normal role is to induce double stranded breaks to relax and stabilise DNA replication). This will prevent DNA relaxation and DNA reannealing which will create multiple DNA double strand breaks.
2) It can indirectly inhibit Helicase by intercalating into DNA and stabilising it, preventing it from being separated.
3) Produce reactive oxygen species which induce DNA/cell damage and apoptosis.
Examples of Anthracyclines
- Doxorubicin- leukaemia, lymphoma and breast cancer
- Epirubicin- breast cancer
- Idarubicin- haematological cancer
Cancer- anti microtubule agents
Disrupts the microtubule spindle which is required for effective separation of the chromatids. Microtubules are also important for cell migration (prevent metastasis), however this will cause a range of side effects as it disrupts normal cell function. Can be separated into Vinca Alkaloids and Taxanes. Affects mitosis but not DNA replication
Types of anti-microtubule agents
- Vinca alkaloids- for example Vinicristine, prevents tubulin assembly, cant assemble the mitotic spindle. Chromatids cant separate, they experience cell arrest during anaphase.
- Taxane- for example Doxetaxel (breast and lung cancer). Prevents tubulin disassembly so you cant contract the mitotic spindle. Experience cell cycle arrest at the M phase checkpoint in Anaphase and die.
Signs and symptoms of the menopause
- Hot flushes / night sweats
- Menstrual irregularities- can be heavier bleeding which occurs more regularly
- Difficulty sleeping
- Reduced sex drive (libido)
- Recurrent urinary tract infections (UTIs), increased frequency of urination, urinating at night
- Poor memory and concentration
- Headaches
- Mood changes, such as low mood or anxiety
- Palpitations
- Joint stiffness, aches and pain- Osteoporosis is the progressive loss of bone mass which alters bone microarchitecture, greater susceptibility to breaks. Osteopenia causes thinning of the bones.
- Reduced muscle mass
What causes the Menopause
Oestrogen withdrawal
Menopause- what causes vaginal dryness, itching or discomfort during sex
Its caused by atrophy, inflammation and reduced collagen. Thinning of the mucosal layer and thickening of the stroma. Thins out the vagina, making it more delicate. Reduction in oestrogen causes a loss in lubrication. There can be a reduction in elasticity making movement difficult and can cause bleeding and itch.
Average age of the menopause
52
Menopause- Vasomotor symptoms
Vasomotor symptoms i.e. hot flushes can by triggered by alcohol/caffeine, exercise and environmental temp changes. Due to the effect of fluctuating oestrogen levels on the thermoregulatory centre. Change to blood flow, blood might shift to the skin causing a feeling of warmth and flushing. Dilation in small blood vessels.
Diagnosing the Menopause
In women over 45 the diagnosis of menopause does not need additional lab tests. Its 12 months since last menstrual period when the women is not using hormonal contraception, diagnosed retrospectively. Usually a transitional stage with irregular cycle and vasomotor symptoms, this is the peri-menopause stage.
How many menstrual cycles in a womens life
400-500