Non-targeted cancer therapies Flashcards
Surgical oncology
Only curative if not metastatic
Removal of large intestine prevents Familial adenomatous polyposis
Mastectomy prevents breast cancer
Commonly used in combined therapy
Fluorescence guided surgery
Enables location of tumour
Peptide with probe bound added. Digested by matrix metalloproteases (secreted by most cancers) to reveal fluorescence
Radiotherapy
Can be used before (neoadjuvant) or after surgery (adjuvant)
Damages normal cells but cancer cells are more sensitive as dividing more rapidly and mutations in DNA repair
External beam therapy (photon/proton)
Brachytherapy
Systemic therapy
Photon radiotherapy
X or gamma ray
Directly ionises DNA or induces free radicals from water.
Induction of DNA damage response leading to cell cycle arrest/DNA repair or apoptosis
Dose delivered as several alignments (damages surrounding tissue)
Proton beam therapy
Causes direct and indirect DNA damage
Deposit energy in a specific area (Bragg point) reducing damage to surrounding tissue
So-far used to treat uveal melanoma
Brachytherapy
Uveal melanoma
Radioactive plaque added to eye near tumour which releases radioactive dose
Systemic therapy
Liquid drug taken by mouth or injection
Contains a radioactive isotope
Can be coupled to a monoclonal antibody to direct to tumour
Treats thyroid, bone and prostate cancers
Radiotherapy resistance
Tissue specific gene expression
Deficient DNA repair mechanisms
Solid tumours often have hypoxic environment (failure to induce free radicals)
When chemotherapy is used
Neoadjuvant to shrink a tumour before surgery or radiation
Adjuvant to kill remaining cells post surgery
Curative as a single therapy
Palliative for patients with advanced/metastatic cancer
Chemotherapy
Disrupts cell proliferation
Most effective against rapidly dividing cells
Non-specific. Normal rapidly dividing cells are affected
Compromised renewal of epithelial barrier
Anti-metabolites
Similar to naturally occurring compounds Inhibit nucleic acid synthesis S phase specific Require active transport Breast cancer, leukaemia, lung cancer
Methotrexate
Antimetabolite
Analogue of folic acid
Inhibits dihydrofolate reductase
Blocks purine and pyrimidine nucleic acid synthesis in S-phase
Anthracyclines
Intercalate into DNA in S and G2 phase
Doxorubicin inhibits Topoisomerase II (DNA correcting enzyme) preventing DNA replication
Breast, bladder and Acute lymphocytic leukaemia
Microtubule binding agents
Complex organic bases Natural and semi-synthetic Microtubule destabilising drugs (Videsine) Microtubule stabilising drugs (Taxol) Result in mitotic arrest
Taxol
Blocks disassembly of the mitotic spindle during cell division through stabilisation of microtubule polymer
Chromosomes unable to achieve metaphase spindle configuration
Breast, ovarian and lung cancer