Epidemiology, Cancer Prevention and Screening
Basic measures
Incidence counts new cases per population-time; prevalence counts existing cases over total population. Age standardisation is essential when comparing populations with different age structures. Mortality and relative survival describe outcome. Five-year survival is inflated by lead-time bias and overdiagnosis, so disease-specific mortality is the preferred endpoint for screening programmes.
Study designs
Ecological studies are group-level and hypothesis-generating; cross-sectional studies measure association at one time; case-control studies yield odds ratios and are prone to recall and selection bias; cohort studies yield relative risks and establish temporal sequence; randomised trials are the reference standard.
Screening principles
Wilson and Jungner criteria: the disease is important, accepted treatment exists, facilities for diagnosis and treatment exist, there is a recognisable latent stage, a suitable and acceptable test exists, natural history is understood, there is agreed policy on whom to treat, and costs are balanced against case-finding. Harms include false positives and the associated anxiety and biopsy, overdiagnosis and interval cancers.
Established programmes
Cervical cytology or HPV testing plus HPV vaccination; mammography in defined age bands; colorectal screening by faecal immunochemical testing, sigmoidoscopy or colonoscopy; low-dose CT for high-risk smokers; hepatitis B vaccination to prevent hepatocellular carcinoma.
Primary prevention
Tobacco control is the single largest lever, followed by weight control, alcohol reduction, physical activity, UV protection and control of oncogenic infections (HPV, HBV, HCV, Helicobacter pylori, Epstein-Barr virus, HIV).
Traps
Confusing incidence with prevalence, crude with standardised rates, and relative with absolute risk. Attributable fraction questions need the prevalence of exposure as well as the relative risk.
Supportive Care, Palliative Care and Oncologic Emergencies
Emergencies to recognise instantly
Febrile neutropenia is fever of 38.3 degrees Celsius once, or 38.0 degrees sustained, with an absolute neutrophil count below 0.5. Take cultures and give empirical anti-pseudomonal beta-lactam within 60 minutes; add vancomycin for line infection, mucositis or haemodynamic instability.
Tumour lysis syndrome: hyperkalaemia, hyperphosphataemia, hyperuricaemia and hypocalcaemia. Prevent with hydration and allopurinol; rasburicase is for high-risk or established disease and is contraindicated in G6PD deficiency.
Malignant spinal cord compression: back pain, motor weakness, sensory level and bladder dysfunction. Give dexamethasone immediately and arrange MRI within 24 hours.
Hypercalcaemia: intravenous saline, then a bisphosphonate or denosumab, with calcitonin for rapid control. SIADH causes euvolaemic hyponatraemia and is managed with fluid restriction. Superior vena cava syndrome usually needs tissue diagnosis before radiotherapy in the stable patient.
Symptom control
The WHO analgesic ladder, opioid conversion and rotation, laxatives for opioid-induced constipation, antiemesis by emetogenic risk (5-HT3 antagonist plus dexamethasone plus an NK1 antagonist for highly emetogenic regimens), mucositis care, fatigue management and VTE prophylaxis in high-risk ambulatory patients.
Palliative care
Early integration improves quality of life. Discuss goals of care, advance care planning and preferred place of death, and recognise the dying phase to stop futile interventions.
Traps
Do not delay antibiotics pending results, do not give rasburicase without checking G6PD, and avoid steroids before lymphoma diagnosis where they can obscure histology.
Ethics, Professionalism and Communication
The four principles
Autonomy (respect for the informed choice of a capacitated patient), beneficence, non-maleficence and justice (fair distribution of scarce resources). When they conflict for a competent adult, autonomy generally prevails, even when the choice seems unwise.
Consent and capacity
Valid consent requires capacity, adequate information and voluntariness. Capacity is decision-specific and time-specific: the patient must understand, retain, weigh and communicate the decision. Best-interest decisions apply only when capacity is absent, and a substitute decision-maker or advance directive should be sought.
Communication
The SPIKES framework (setting, perception, invitation, knowledge, empathy, strategy and summary) structures the breaking of bad news. Avoid false reassurance and jargon, and check understanding with teach-back. Cultural and religious context, interpreter use and family involvement preferences vary and must be respected without overriding the patient's own wishes.
Professionalism
Confidentiality, with limited exceptions such as serious risk of harm or legal obligation; appropriate boundaries; honesty about errors and disclosure of adverse events; management of conflicts of interest; and the duty to report impaired colleagues.
Research ethics
Institutional review board approval, informed consent, clinical equipoise, risk minimisation and the Declaration of Helsinki. Placebo-controlled oncology trials are acceptable only when no proven effective treatment exists, or when standard treatment is given to both arms.
Resource allocation
Triage decisions should be transparent and consistent, based on clinical need and likelihood of benefit, never on social worth.
Traps
A patient refusing curative treatment is exercising autonomy, not demonstrating incapacity, and confidentiality may be breached only where law or serious public risk requires it.
Rule of thumb
If you would not defend the decision before the patient, the family and a tribunal, it probably violates one of the four principles.