Oncology Flashcards
What is chemotherapy in general?
Group of cytotoxic agents used to SYSTEMATICALLY manage cancer
Why is it necessarily for chemo to systemically Tx patients, rather than being just localised?
Metastasis kills patients, not local recurrence in primary organ
What is the % of people with cancer who will require chemotherapy?
60-70%
What is the mechanism by which chemo exerts its anti-cancer action?
Most target DNA directly/indirectly
Preferentially toxic to actively proliferating cells ∴ work best on rapidly dividing tumours
What are the uses for chemo?
- NEOADJUVANT - Tx of operable tumour pre-op to reduce its size ∴ allow for less radical Tx. Also Tx micro mets.
- PRIMARY - initial Tx for inoperable tumour - reduce tumour bulk to allow surgical resection (↑ cure rates)
- ADJUVANT - post op Tx for micro mets after complete resection (↑ cure rates)
- PALLIATIVE - relieve Sx and prolong life when incurable. Balance so not to ↓ QoL
- CURATIVE - mostly germ cell, (non)Hodgkin’s lymphoma, childhood cancer WITHOUT surgery, even with mets! ∴ justifies intensive Tx with ↑ toxicity
- PROPHYLACTIC - hormonal Tx before overt malignancy appears e.g. tamoxifen for in-situ breast cancer before invasive carcinoma
Cytotoxic chemo is most commonly given in combo of different drugs. Why is this?
- Different mechs of action give highest chance of result (several sub-lethal cell injuries can kill cell in combination- synergism)
- ↓ chance of drug resistance
- Different drugs = different toxicity effects ∴ dose can be maintained
How are most schedules of chemotherapy treatments given?
Cyclically - every 3-4 weeks
Why are chemotherapy treatments scheduled cyclically (i.e. every 3-4 weeks)?
Allows normal cells to recover from toxicity - low blood counts (myelosuppression) and mucositis
Repeated cycles required for full clearance as only a proportion of tumour cells killed each time
Why are many chemotherapy treatments only maximally effective after a 6 month course?
Due to resistance emergence (chemo sensitive die and resistant remain ► replicate) and increased toxicity
Why do most people with cancer take conventional doses of chemotherapy?
Known to be effective against the particular malignancy in majority of PTs
Side effects are tolerable
Why is it bad to take high doses of chemo?
Higher toxicity, and potentially lethal SEs (1-2% mortality) (bone marrow suppression) → specialised supportive care required (GFs, rescue stem cells/bone marrow, ABx)
What cancers are ones where high doses of chemo are justified?
High doses justified only when long term survival or cure possible (HELL-MUG):
Hodgkins
Ewing’s sarcoma
Leukaemia
Lymphoma
MUltiple myeloma
Germ cell tumours of testis
Why is prolonged chemotherapy to maintain remission not advised/advantageous?
Increased resistance and toxicitiy
What condition/group of patients is maintenance chemotherapy advised?
Childhood Leukaemia - 18 months maintenance Tx post remission
What is the advantage of giving chemo orally?
Freeing the patient from lenghty hospital visits and invasive procedures
What is the disadvantages of taking chemo orally?
- Doesnt reduce toxicity - requires regular review
- Only few chemo drugs avaliable orally (cyclophosphamide, etoposide, capecitabine, tamoxifen)
- Absorption issues can effect levels in circulation
How is most chemotherapy given?
IV mostly as bolus injection or short infusion.
Can be continuous infusion via central line
Chemotherapy Tx can be administered regionally. What are the methods?
Intravesical - high doses given at site, ↓ systemic absorption and toxicity e.g. superficial bladder cancer
Intraperitoneal - for trans-coelomically spread tumour e.g. ovarian cancer
Intra-arterial - for tumours with well-defined blood supply (e.g. hepatic artery infusion for liver mets). ↑ doses to involved site ↓ systemic absorption
How are chemotherapy doses calculated?
Most calculated according to patients body surface area (DuBois and DuBois formula):
BSA = (Weight (kg) 0.425 x Height (cm) 0.725) x 0.007184
Others:
- Carboplatin - renal function
- Newer drugs e.g.traztuzumab - body weight
What type of ADVANCED cancers is chemo most effective (i.e. cure of advanced disease in >50%)
Hodgkins disease
Testicular/germ cell cancers
Acute lymphoblastic leukaemia
Choriocarcinoma
Paediatric cancers e.g. leukaemia, lymphoma, sarcoma
What are the ADVANCED cancers where chemo is less effective (<50% cure)
Non-Hodgkins
Ovarian cancer
Paediatric Neuroblastoma
Osteosarcoma, Ewings Sarcoma, Rhabdomyosarcomas
What types of REGIONAL cancers will chemo increase cure rates?
Breast
Colorectal
Non-small cell Lung
Oesophageal/gastric
Bladder
What types of cancer will chemo result in remission in most pts?
Those in list of curable cancers.
Breast
Small cell lung cancer (very chemo sensitive)
Ovarian cancer
What types of ADVANCED REGIONAL cancer will chemo prolong survival but NOT cure in most?
Non-small/small cell lung cancer
Colorectal cancer
Gastric cancer
Breast cancer
Bladder
Prostate
What types of cancer is chemo only really effective for pallitation of Sx?
Renal Cancer
Melanoma
Head and neck cancer
Pancreatic
Billiary Tract cancers
What are the IMMEDIATE GI SEs of chemotherapy
N&V - direct stimulation of vomiting centre, peripheral stiumlation and anticipatory.
GI - rapidly dividing cells ∴ susceptible.
- Mucositis (especially oral)
- Diarrhoea (colitis/inflammation)
- Constipation (dehydration, other drugs e.g. opioids)
What are the IMMEDIATE bone marrow related SEs of chemotherapy?
Myelosuppression - kills haematopoietic progenitor cells.
- ↓WCC (< 1 x 109), ↓platelets (rare if standard doses used) - after 10-14 days.
- Higher doses - cause worse/longer leucocyte fall (but drug dependent)
- Lowest point of drop = nadir.
- Recovery after 3-4 weeks.
What are the immediate hair related SEs of Chemo?
Alopecia - hair follicles rapidly dividing (reversed with discontinuation) - ↓ with cold cap
What are the immediate neurological SEs of chemotherapy?
- Peripheral/Autonomic neuropathies (mainly sensory) (e.g. cisplatin, taxanes, vinca alkaloids)
- Central toxicity - ifosfamide induced encephalopathy, 5-FU induced cerebellar toxicity
- Ototoxicity (e.g. pernament cochlear damage with cisplatin)
What are the immediate genitourinary SEs of chemotherapy?
- Nephrotoxicity - e.g. cisplatin, ifosfamide - renally excreted ∴ adequate renal func required
- Bladder toxicities e.g. cyclophosphamide, ifosfamide - haemorrhagic cystitis