Therapeutic options in Cancer Flashcards
Describe modalities of therapy currently available
Prevention: • Diet • Reduced environmental factors e.g. smoking • Screening • Genetics • Medication
Treatment:
• Surgery
• Radiotherapy
• Systemic therapy - chemotherapy, immunotherapy
How is diet linked to colorectal cancer?
Linked to red meat consumption
How is diet linked to breast cancer?
Linked to saturated fat intake
Describe some currently available cancer screening schemes
- Cervical cancer: smear tests, HPV injections
- CRC: faecal occult blood
- Breast cancer: mammography
More controversial, is it of benefit to patient:
• Prostate cancer: PSA blood test (reliable?)
• Lung cancer: MR / CT scanning, breath test
Describe some chemoprevention commonly used
Primary: oesophageal cancer
- High rates in parts of China
- Supplement diet with anti-oxidants, not much difference
Primary: breast cancer
- Known at risk women
- Prophylactic tamoxifen, benefit vs. harm (side effects) e.g. increases risk of endometrial cancer
Secondary: previous H&N or lung cancers
- Give anti-oxidant supplements
- No benefit
Describe some mechanisms of local cancer treatment
- Surgery
- Radiotherapy
- Ablation (freezing, radio-frequency, etc.)
- Isolated limb perfusion
Describe some methods of systemic treatment
- Hormonal therapy
- Chemotherapy
- Immunotherapy
- Whole body irradiation (for bone marrow transplant)
What are the 5 Rs of radiobiology?
- Radiosensitivity – How sensitive is it to radiotherapy?
- Repair – allows repair of normal cells, not necessarily cancer
- Re-population – allows repopulation of normal cells, while ideally not allowing tumour growth
- Re- oxygenation – hypoxic cells resistant to radiation, splitting the dose into fractions raises the possibility of the closed vessel being open the next time around, and therefore allowing the tumour cells to be killed.
- Re-assortment – allows targeting of cells in different stages of cell cycle during different treatments
What is total mesolectal excision?
Total mesorectal excision is a standard technique for treatment of colorectal cancer. A significant length of the bowel around the tumour is removed, and the removed lymph system scrutinised for cancerous activity (see lymphadenectomy). It is possible to rejoin the two ends of the colon; however, most patients require a temporary ileostomy pouch. Local treatment.
What is prostate brachytherapy?
Localised treatment where tiny radioactive particles the size of a grain of rice are implanted directly into the site of the tumour. These particles are known as ‘seeds’, and they can be inserted linked together as strands, or individually. Because the seeds are inserted or implanted directly into, or very close to, the tumour, they deliver high doses of radiation to the tumour without affecting the normal healthy tissues.
Where in the cell cycle are cancer cells not susceptible to radiotherapy?
G1 quite unsusceptible, and no effect in G0 (no treatment kills senescent cells)
Define the therapeutic index
Represents the difference between the lowest therapeutic concentration and the concentrationt that causes toxicity in patients
What is a neoadjuvant?
‘Neoadjuvant’ – chemotherapy given beforehand e.g. increase success of surgery/radiation
What are some important biomarkers for metastatic CRC?
- Kras status
* Braf status
Give some examples of hormone therapy for cancer treatment
- Breast cancer: ER+ve & tamoxifen
* Prostate cancer: LHRH antagonists
