Chemotherapy Flashcards
What is chemotherapy?
- Generally refers to group of ‘cytotoxic’ agents used in systemic management of cancer
- treatment to erradicate occult cancer cells must include effective systemic treatment
What are the mechanism of action of chemotherapy?
- most agents target DNA either directly or indirectly
- preferentially toxic towards actively proliferating cells
- tumours which divide rapidly, with short doubling times, usually respond best to chemo
What are the indications for giving chemotherapy?
- Pre-operative treatment of operable tumour before definitive surgical intervention
- aim to make tumour smaller
- used in osteosarcoma
- Primary tumour that is inoperable
- Adjuvant =alongside complete macroscopic clearance at surgery
- treats occilt microscopic metastases
- Palliative =to alleviate symptoms / prolong life
- Curative =realy chance of cure justifies more intensive treatment
- Prophylactic
- hormonal treatment given before overt malignancy appears
- tamoxifen
Why are cytotoxic chemotherapy commonly given as a combination of different drugs?
- different classes of drugs have diffeent action and may kill more cancer cells
- less chance of drug-resistant malignant cells emerging
- when drugs with different sites of toxicity are combine, dose can be maintaine for each drug
What is the classic treatment schedule of chemotherapy?
- Given cyclically to allow normal cells to recover from toxicity of treatment
- Cells usually affected by chemo at standard dose are haematopoietic stem cells and lining of GI tract, producing low blood counts and mucositis
- Giving the treatment every 3-4 weeks allows these cells to recover
- Repeated cycle required to get tumour clearance
- Most 6 month course = maximally effective
What is maintenance treatment in chemotherapy? When is it used?
- Following the induction of complete remission chemotherapy still given for time after to maintian remission
- Used in childhood leukaemia 18 months after remission
What are the different routes of administration of chemotherapy?
- Orally
- Systemically
- Regionally
- intravesical
- intraperitoneal
- Intra-arterial
How do you calculate the dose for chemotherapy drugs?
- Body sruface area calculation
- Carboplatin only dug that dose calculation is done according to renal function
What are some of the immediate side effects of chemotherapy and what systems do they affect? Further specific details given later.
- Nausea and vomiting
- Alopecia
- Myelosupression
- GI side effects
- Neurological
- Genitourinary
- Cardiac
- Hepatic
- Skin and soft tissue toxicity
- Myalgia and arthralgia
What are some of the long term side effects of chemotherapy?
- Second malignancies
- some lead to genetic changes required to induce a second malignancy
- Reduction in fertility
- Pulmonary damage may result from bleomycin
- Cardiac fibrosis may occur due to doxorubicin
- Psychological and social impact
What is myelosuppression? How doe chemotherapy cause this?
- Chemo causes bone marrow suppression by killing haematopoietic progenitor cells
- Leads to leucopenia and thrombocytopenia 10-14 days from the beginning of each cycle
What is the management of myelosuppression? Consider management of:
- Anaemia
- Thrombocytopenia
- Neutropenia
- Anaemia
- may benefit from blood transfusions
- recombinant erythropoetin injection
- Thrombocytopenia
- single donor or HLA matched platelets
- Neutropenia
- neutropenic infection =broad spectrum antibiotics
- Blood cultures, urine, sputum and throat + Chest X-Ray
What is the total white count cut off for immediate in-patient management for suspected neutropenic sepsis?
- White count of less than 1 x 10^9/L
- with associated fever
How is neutropenic sepsis prevented?
- Prophylactic antibiotics -considered in certain condition e.g. COPD but not ususally used
- Dose reduction if sepsis associated with current dose
