Chemo and radiotherapy Flashcards
What is chemotherapy
The use of any chemical substance to treat disease
The use of cytotoxic drugs in the treatment of cancer
What is the aim of chemotherapy?
Deliver enough cytotoxic drug to a cancer cell target which is expressed drug to a cancer cell target which is expressed differently to normal tissue
How frequently is chemo given?
In intervals
Why is chemo given in intervals?
To allow the normal tissue to recover
What method of cancer treatment is systemic
Chemo
Why are single chemotherapy agents rarely used
Genetically resistant cells are selected out
Why is it important for chemo to be systemic
Either due to metastases or the potential to metastasise in the future
Why is it advantageous for chemo to be a combination?
Different mechanisms of action and different side effect profiles reduces the likelihood of resistance and toxicity
What qualities should chemotherapy drugs have
Cytotoxic activity for that tumour, preferentially able to induce remission
Different mechanisms of action, ideally additive or synergistic effects
Non-overlapping toxicity to maximize benefit of full therapeutic doses
Different mechanisms of resistance
What is adjuvant chemo?
After other initial treatment to reduce the risk of relapse
What is neoadjuvant chemo?
Used to shrink tumours prior to surgical or radiological treatment - may allow later treatment to be more conservative
What is palliative chemo?
No curative aim, offers symptom relief may prolong survival
What are alkylating agents
Anti-proliferative drugs that bind via alkyl groups to DNA leading to apoptotic cell death
Give some examples of alkylating agents
Cyclophosphamide
Chlorambucil
Bulsulfan
Give examples of angiogenesis inhibitors?
Bevacizumab, aflibercept, sunitinib
What are antimetabolites
Interfere with cell metabolism including DNA and protein synthesis
Give examples of antimetabolites
Methotrexate
5-flurouracil
What are antioestrogens
Aromatase inhibitors (letrozole, anastrozole) Oestrogen receptor antagonists (tamoxifen, raloxifene)
What are anti tumour antibiotics
Interrupt DNA function
Give examples of anti-tumour antibiotics
Dactinomycin
Doxorubicin
Mitomycin
Bleomycin
What are monoclonal antibodies
Antibodies to a specific tumour antigen can slow tumour growth by enhancing host immunity or be conjugated with chemo/radioactive isotopes to allow targeted treatment
What are topimerase inhibitors
Interrupt regulation of DNA winding
Give an example of a topimerase inhibitor
Etoposide
What are vinca alkaloids
Spindle poison which target mechanisms of cell division
Give an example of a vinca alkaloid
Vincristine
Vinblastine
Docetaxel
List the main side effects of chemo
Vomiting
Alopecia
Neutropenia
Infertility
Which cells experience more of the effect from chemo
Rapidly dividing cells - gut, hair, bone marrow, gametes
What is extravasation of chemo
Inadvertent infiltration of a drug into the subcutaneous/subdermal tissue
How does extravasation of chemo present
Tingling, burning, redness, swelling, no flashback/resistance from cannula
Describe the management of extravasation of chemo
Stop and disconnect infusion
Aspirate any residual drug before cannula removed
Follow local policies and any drug specific recommendations
DNA binding drugs - use a dry cold compress to vasoconstrict and reduce drug spread
Non-DNA binding drugs - use a warm compress to vasodilate and increase drug distribution
Describe how chemo and radiotherapy may lead to infertility
Damage spermatogonia causing impaired spermatogenesis or male infertility
Hasten oocyte depletion leading to premature ovarian failure
What should be done prior to treatment if the treatment carries a risk of infertility
Men - semen cryopreservation
Women - cryopreservation of embryos, oocytes and ovarian tissue. Ovarian transposition (oophropexy) may be possible prior to pelvic radiation but protection is not guaranteed due to radiation scatter
Describe the mechanism of action of radiotherapy
Uses ionizing radiation to cause damage to the DNA
Prevents cell division and causes cell death
The aim of radiotherapy treatment is to inactivate cancer cells without causing a severe reaction in normal tissue
Describe radical radiotherapy treatment
Given with curative intent
Total doses range from 40-70 gray (Gy) in up to 40 fractions
Some regimens involve several smaller fractions a day with a gap of 6-8hrs.
Combination chemo is used in some sites such as oesophagus to increase response rates
Describe palliative radiotherapy
Aims to relieve symptoms and may not impact on survival
Doses are smaller and given in fewer fractions to offer short term tumour control with minimal side effects. Palliation is used for brain metastases, spinal cord compression, visceral compression and bleeding
Bone pain from metastasis can be reduced or eliminated in 60% cases
List some early reactions of radiotherapy
Tiredness Skin reactions Mucositis Nausea and vomiting Diarrhoea Dysphagia Cystitis
List some late reactions of radiotherapy
CNS/PNS - somnolence, spinal cord myelopathy, brachial plexopathy
Lung - pneumonitis
GI - xerostomia, benign strictures, fistulae, radiation proctitis
GU - urinary frequency, vaginal stenosis, dyspareunia, erectile dysfunction
Endocrine - panhypopituitarism and hypothyroidism
Secondary cancers
List the methods of giving radiotherapy
Conventional external beam radiotherapy (EBRT)
Stereotactic radiotherapy
Brachytherapy
Radioisotope therapy
Describe conventional external beam radiotherapy
Delivers a beam of ionizing radiation to the patient from an external linear accelerator
Describe stereotactic radiotherapy
Highly accurate form of EBRT
Used to target a small lesion with great precision
Often referred to by the manufactures name eg. Gamma knife
Describe brachytherapy
Involves radiation source being placed within or close to a tumour, allowing high local radiation dose. Implants may be placed within a cavity or within tissue
Describe radioisotope therapy
Uses tumour seeking radionuclides to target specific tissues
What is interventional oncology
Interventional radiology procedures used in palliative care/cancer treatment.
Can be divided into disease modifying and symptomatic procedures
Describe disease modifying interventional oncology
Intended to modify cancer progression and/or to improve prognosis Includes: Image guided ablation Embolization Image guided brachytherapy Isolated perfusion chemotherapy
Describe symptomatic interventional oncology
Provides relief from cancer related symptoms but does not modify the underlying disease process. The techniques can offer significantly improved quality of life, reduce admissions and increase time spent out of hospital
Name the interventional treatment option of ascites or pleural effusions
Temporary/permanent image guided drain
Name the interventional treatment option of oesophageal/large bowel obstruction
Stenting
Name the interventional treatment option for tumour related haemorrhage
Trans arterial embolisation
Name the interventional treatment option for jaundice
Biliary drainage and stenting
Name the interventional treatment option for renal tract obstruction
Nephrostomy
Ureteric stenting
Name the interventional treatment option for bone metastases
Image guided ablation
