Cancer Therapy Flashcards
(43 cards)
What is the meaning of adjuvant therapy?
Treatment given in addition to the primary therapy, eg. chemo, radio, hormone treatment
What is the meaning of neoadjuvant therapy?
Treatment given to shrink the tumour before the primary treatment
What are the functions of surgery in cancer treatment?
Prevention, diagnosis, staging, primary treatment, debulking, relieving symptoms/side effects
When is and when isn’t surgery appropriate for treatment of cancer?
Surgery is most often used when tumours are at their early stage, or are localised and solid. Surgery is not suitable for systemic cancers or those that have metastasised to risky areas such as major blood vessels
What usually happens in surgery?
The main aim of surgery is to remove the whole tumour/host organ. The surrounding healthy tissue is also removed to reduce the chance of recurrence. Some lymphatic system may also be removed. Surgery if often used in combination with other modalities of treatment. Can also be used to alleviate symptoms
What are the risks of surgery?
Bleeding, blood clots, damage to nearby tissues and nerves, adverse reactions to surgery drugs, damage to other organs, pain, infections, slow recovery of other body functions
What are the main types of surgery?
Debulking - before chemo or radio, removes most of tumour, improving chances
Laparoscopic - “keyhole”, uses laparascope (small tube) with camera and light source to guide the surgery
Radical - Removes all nearby tissues eg. nerves, lymph nodes, muscles
Preventative (prophylactic) - Removes non cancerous tissues in high risk patients eg. with BRCA1/2 mutations
How does radiotherapy work?
Uses ionising radiation, usually delivered by linear accelerator, to kill malignant cells via DNA damage. Can be curative when the tumour is localised. The radiation is delivered to match the 3D shape of the tumour so that healthy cells are not affected. Renal cell carcinoma is radioresistant, and can’t be used in metastatic cancers. Radio usually given over time to allow the cells to recover.
What are the different types of radiotherapy?
3D conformal radiotherapy - Use computer programmes to analyse tumour and design radiowaves in that shape
Intensity modulated radiotherapy - 3D shape divided into segments and different intensities used for different segments
Image guided radiotherapy - Used to treat tumours in areas that move eg. lungs. Frequent images taken before and during surgery to assist in precise delivery to the tumour
Stereotactic body radiation - Use imaging and computer modulation to deliver high intensity doses of radio. Given in single/few treatments as an alternative to surgery in small tumours
Brachytherapy - Radioisotope source placed in sealed container inside the body near the tumour
What is the mechanism of action of radiotherapy?
Ionising radiation has enough energy to knock the electron off of an atom, forming an ion. This can directly damage DNA, or form free radicals from H2O which damage DNA. DNA repair mechanisms often significantly disrupted in cancer cells, so this can lead to apoptosis. Also, the sheer amount of damage can overwhelm these mechanisms. Mitotic catastrophe, IR-induced senescence, necrosis, and autophagy can happen. When dsbreaks occur, sensor proteins (PARP, MRN) recruit transducer proteins ATM/ATR which phosphorylate H2AX which is maintained by mediator proteins, effector proteins are signalled to which lead to apoptosis
What is mitotic catastrophe?
Mitotic catastrophe is when cells enter mitosis prematurely or inappropriately.
What are the side effects of radiotherapy?
The healthy cells receive some radiation, however they repair much more effectively due to their intact repair mechanisms. They’re still able to be damaged.
Sore red skin, fatigue (low rbc, energy used for repair), hair loss, nausea, loss of appetite, sore mouth, diarrhoea, lymphedema (damaged lymphatic system -> swelling)
What is chemotherapy?
Chemotherapy uses cytotoxic drugs to kill cancer cells. It is systemic, given orally or via IV, and given in cycles with recovery periods inbetween. It targets dividing cells at various stages of the cell cycle. The fact that it targets rapidly dividing cells means that it can also affect normal cells ie. digestive tract, reproductive system, hair
How can chemotherapy be used?
It can be adjuvant, neo-adjuvant, or solo. Mitomycin, Ifosfamide, Cisplatin (MIC) is used for non small cell lung, and oesophageal cancer
Cyclophosphamide, Doxorubicin, Oncovin (Vincristine), Prednisolone (CHOP) used for Non H lymphoma and chronic lymphocytic leukaemia
What are alkylating agents and how do they work?
Alkylating agents add an alkyl group to G in the DNA, crosslinking the strands so that the DNA can’t unwind during replication, stalling replication at the DNA checkpoint, leading to apoptosis. They also encourage mispairing during DNA repair. Toxic to normal cells, especially fast dividing ones.
What are the side effects of alkylating agents?
Hair loss (carboplatin), nephrotoxicity, neurotoxicity, ototoxicity (ear, platinums), nausea, vomiting, diarrhoea, immunosuppression, tiredness
What are antimetabolites and how do they work?
They interfere with DNA synthesis enzymes. They masquerade as purine/pyramidine residues, inhibiting replication and transcription. Can be folate antagonists, inhibiting dihydrofolate reductase which produces folic acid, a DNA building block. They induce apoptosis in S phase when DNA is being synthesised
What are the side effects of anti-metabolites?
Fatigue, alopecia, BM suppression -> anemia, low wbc & platelet, increased risk of neutropaenic sepsis (inflammatory response to infection) or bleeding, nausea and vomiting, mucositis, diarrhoea, palmar-plantar erythrodysesthesia (red, swell, numb, skin sloughing off palms and soles)
What are anti-microtubule agents and how do they work?
They inhibit cell proliferation by binding to and suppressing microtubule dynamics in the mitotic stage. Vinca alkaloids and taxanes inhibit assembly and disassembly of mitotic microtubules which leads to mitotic arrest and cell death. They’re also anti-angiogenic
What are the side effects of anti-microtubule agents?
Peripheral and autonomic neuropathy, alopecia, nausea, vomiting, decreased blood cell production in bone marrow (myelosuppression), joint pain (arthralgia), allergy
What are topoisomerase inhibitors and how do they work?
They bind to and inhibit the religation of DNA by topoisomerase, which results in DSBs that build up and lead to apoptosis.
What are the side effects of topoisomerase inhibitors?
Irinotecan: acute cholinergic type syndrome (diarrhoea, ab cramps, sweating. Given with atropine to block aberrant nerve impulses
Hairloss, nausea, vom, fatigue, myelosuppression
What are cytotoxic antibiotics and how do they work?
They’re naturally occuring drugs that are good at killing cancer cells. They generally interrupt cell division. The main groups are anthracyclins, bleomycins. The main mechanisms are intercalating DNA preventing replication and transcription, inhibiting Top II, producing free radicals to damage DNA, damaging cell membranes.
What are the side effects of cytotoxic antibiotics?
Cardiac toxicity (arrythmia, heart failure), alopecia, neutropaenia, nausea, vomiting, fatigue, skin changes, red urine
