Clinical Oncology Basics

Overview – Clinical Oncology Basics

Clinical oncology basics encompass the foundational principles of managing cancer patients, including diagnosis, staging, and treatment using surgery, chemotherapy, radiotherapy, and supportive care. The overarching aim of oncology is to cure cancer when possible, and when not curable, to prolong survival and optimise quality of life. Management is multi-disciplinary and guided by the type, stage, and biological behaviour of the malignancy.

Aim of Clinical Oncology

• Primary aim: Cure the cancer (when possible)
• If not curable:
  • Control tumour growth
  • Alleviate symptoms
  • Prolong life and improve quality of life (QOL)
• Note:
  • Some cancers (e.g. germ cell tumours, lymphoma, leukaemia) are curable
  • Most metastatic disease is not curable

Managing Cancer Patients

Key Disciplines

• Medical Oncologist
  • Chemotherapy
  • Hormonal therapy
• Radiation Oncologist
  • External beam radiotherapy
  • Brachytherapy: Radioactive source placed within/near tumour
  • Systemic radiation
• Oncological Surgeons
  • Definitive or palliative resections
• Allied Health Support
  • Dietetics, physiotherapy, occupational therapy, social work
• Palliative Care Specialists
  • Symptom control (not limited to terminal patients)
  • End-of-life care

Stepwise Approach to Cancer Management

1. Diagnosis – What Type of Cancer?

• Imaging:
  • Chest X-ray (largely obsolete)
  • CT scan
  • Bone scan: Detects osteoblastic activity
  • PET scan: Radiolabelled glucose uptake (high in metabolically active tissue)
  • MRI: Especially for CNS tumours

2. Staging

• Determines extent of disease (early vs locally advanced vs metastatic)
• Often uses TNM system (Tumour, Nodes, Metastasis)
• Requires:
  • History and examination
  • Tumour markers:
    • α-fetoprotein (AFP)
    • β-hCG
    • Carcinoembryonic antigen (CEA)
    • Prostate-specific antigen (PSA)
  • Blood tests: FBC, LFTs, bone marrow biopsy if relevant
  • Imaging: CT, MRI, PET, bone scan

3. Prognosis – Is It Curable?

• Prognostic markers:
  • Tumour size
  • Histological differentiation
  • Lymph node involvement
  • Presence of metastasis

4. Treatment – If It Is Curable

Surgery

• Often curative in early-stage disease
• May also be used as debulking prior to adjuvant therapy

Chemotherapy

• Cytotoxic drugs that block DNA synthesis or cell division
• Mechanisms:
  • DNA cross-linking (platinum compounds)
  • Alkylation
  • Microtubule disruption
  • Topoisomerase inhibition
• Side Effects:
  • Nausea/vomiting
  • Myelosuppression
  • Alopecia
  • Infertility
  • Risk of secondary malignancy
  • Multi-organ toxicities
• Curative: Leukaemia, lymphoma, germ cell tumours
• Adjuvant: Breast, colon, ovarian cancers

Biological Agents

• Monoclonal antibodies:
  • HER2+ breast cancer
  • EGFR+ cancers
  • CD20 in lymphomas
  • Action: Block receptors or trigger immune-mediated killing
• Anti-angiogenic therapy:
  • VEGF inhibitors – starve tumour blood supply
• Tyrosine kinase inhibitors (TKIs):
  • Eg: Imatinib (Glivec) in CML or GIST
  • Block EGFR signalling pathways

Hormonal Therapy

• Breast Cancer:
  • Tamoxifen: Blocks oestrogen/progesterone receptors
  • Aromatase inhibitors: Prevent oestrogen synthesis
• Prostate Cancer:
  • Androgen deprivation therapy

Radiotherapy

• Types:
  • External beam radiotherapy (EBRT): Localised, non-invasive
  • Brachytherapy: Internal placement of radioactive material
• Indications:
  • Curative
  • Adjuvant
  • Palliative
• Mechanism: DNA damage to tumour cells
• Side Effects: Local tissue injury
• Delivered in fractions over days to weeks

Palliative Care

• Not limited to end-of-life
• Includes:
  • Pain management
  • Anti-emetics
  • Nutritional support
  • Physio/occupational therapy
  • Psychosocial support
• Palliative chemo/radio may reduce tumour burden, relieve symptoms, and enhance QOL

5. Management – If Not Curable

• Goals:
  • Prolong survival
  • Control symptoms
  • Maximise comfort and function
• How chemo or radiotherapy helps QOL:
  • Shrinks tumour → reduces pain/compression
  • Reduces analgesic burden
  • Stabilises disease to extend life

Summary – Clinical Oncology Basics

Clinical oncology basics form the foundation of effective cancer care, integrating diagnostic imaging, prognostic evaluation, and multi-modal treatment across curative and palliative goals. Management is tailored to tumour type, stage, and biology, with the central aim of curing where possible, and optimising symptom control and survival where not. For a broader context, see our Genetics & Cancer Overview page.