Cancer treatment Flashcards
surgery
-oldest effective cancer therapy
-it can be used alone or in combination with other modalities
-technqiues include resection of metastases, tumor debulking, paliative and reconstructive surgery
primary tumor resection
If tumor has not metastasized
-Chemotherapy and radiation therapy must be given before to reduce cancer size, limit extent of surgery and increase success rate
Radiation therapy
-mainly cures localised cancer that can be completely encompassed within a radiation field
-radiation + surgery for head, neck, laryngeal or uterine
Radiation+surgery+chemotherapy for sarcomas, breast, oesophageal, lung or rectal
-Types include photons, electrons, protons, alpha particle, radionuclides
Neoadjuvant therapy
Given before surgery or chemo
Adjuvant therapy
After surgery or chemo
How radiation works
It damages DNA of cancer cells and causes mitotic catastrophe via single or double stranded breaks. This can be direct DNA damage or indirect via the formation of reactive oxygen species like hydroxyl radicals that do damage
-Normal cells have DNA repair mechanisms while cancer does not
Gamma Knife
Directs highly precise dose of radiation to tumor and avoids healthy tissue around
Brachytherapy
-It involves placing radioactive material inside the body to treat certain cancers
next generation therapy
uses nanoparticles and non-ionising radiation
Nano particles
-The surface of the particle is coated with a molecule that binds to the surface of cancer which facilitates endocytosis
-The particles contain molecules that generate reactive oxygen species or heat when exposed to light
-Not as effective in hypoxic tissue
-Can also be radioactive which allows for far more directed doses as the use of radioisotopes such as alpha emmiters has the potential to limit death of healthy cells surrounding tumor
chemotherapy
-Use cytotoxic drugs that damage DNA (crosslinkers) or inhbit DNA synthesis (anti-metabolites)
-Causes death due to non DNA repair mechanisms
-P53 mutations make cells less sensitive to these drugs as P53 is needed
E.crosslinkers
cisplatin
nitrogen mustards
mitomycin C
E.DNA intercalaters
doxorubicin
(topoisomerase inhibitor)
E.Antimetabolites
fluorouracil (thymidylate synthetase inhibitor)
Methotrexate (tetraydrofolate synthesis inhibitor)
Endocrine therapy
-uses drugs that inhbit cancer growth for cancers that overexpress hormone (androgens) receptors and respond to hormones in a way that promotes survival and growth such as prostate and breast cancers
E.Endocrine
Tamoxifen is a drug that was developed in 1960s and acts as oestrogen antagonist and blocks hormone from binding to cell to reduce oestrogen dependant cancer
Bicalutamide is a testosterone anatagonist for prostate cancer
Immune therapy
Active
Adoptive
Active immunotherapy
Treatment is mediated by active immunity and aims to provoke or amplify a patient’s anticancer immune response
eg: Vaccines, modified T-cells from patient, monoclonal antibodies
Adoptive immunotherapy
Treatment is mediated by passive immunotherapy and involves anticancer antibodies or T cells from healthy individuals that target cancer cells
Car-T Cells
CAR T-cell therapy is used to eradicate very advanced leukemias and lymphomas and to keep cancer at bay for many years
-cytotoxic T cells are removed from cancer patients blood and genetically engineered to express a CAR receptor (chimeric antigen receptor) that targets cancer cells and are returned to patient intravenously
CAR
chimeric antigen receptor
Checkpoint inhibitors
PD1 is a checkpoint receptor on the surface of immune cells that prevents them from attacking self-antigens and causing autoimmune disease
-Cytotoxic T cell with PD1 will engage with ligand PD-L1 and become inactivated
-Tumor cells express large amounts of PD-L1 to inactivate cytoxic T cells
-Monoclonal antibodies bind to PD-L1 which allows T cells to ignore PD1 signal and attack cancer cells
Monoclonal antibody therapy
-targets specific cancer receptors
-HER2 protein is over expressed on breast carcinoma cells and these cells are typically aggressive and have a poor prognosis
-Trastuzumab is a monoclonal antibody that targets Her2 as Herceptin
Anti-angiogenesis drugs
-Monoclonal antibodies that block VEGF
differentiating promoting drugs
include hypo-methylating drugs such as azacitidine which treats leukaemias
Targeted drug therapies
-inhbit overexpressed or overactive proteins
-Eg: Gleevac which is a tyrosine kinase inhibitor
Oncolytic viruses
-viruses are designed to preferentially infect and lyse cancer cells
-it is designed to activate the immune system against a tumor which results in cancer eradication and immune system memory
-it was noted in 20th century
-Hepatitis was used in 1950-1980 as a simplistic approach
-Now use genetically engineered viruses
