Targeted Therapy — Precision Molecular Cancer Care

Targeted therapy refers to a class of pharmacological agents designed to inhibit specific biochemical molecules necessary for neoplastic transformation, tumour progression, and survival. Unlike standard cytotoxic chemotherapies, which broadly attack rapidly dividing cells, targeted agents zero in on defined molecular aberrations identified through comprehensive genomic profiling.

These therapies are primarily categorised into small-molecule inhibitors and monoclonal antibodies. Small molecules penetrate cell membranes to block intracellular enzymatic pathways (such as tyrosine kinase activity), whereas monoclonal antibodies bind to specific extracellular receptors, preventing ligand activation or flagging the malignant cell for immune-mediated destruction.

Targeted therapy has transformed management for many cancers by offering more personalised, effective options with distinctive toxicity profiles. Understanding whether your cancer has actionable targets guides your diagnostic pathway, as specialised molecular testing must precede treatment decisions. Knowing how these drugs work helps patients navigate targeted side effects, such as rash, diarrhoea, or elevated blood pressure, and reinforces the importance of consistent medication adherence to prevent drug resistance.

Eligibility requires biomarker testing on tissue or liquid biopsy samples. Techniques include Next-Generation Sequencing (NGS), Polymerase Chain Reaction (PCR), and fluorescence in situ hybridisation (FISH) to detect mutations, gene amplifications, or fusions that indicate susceptibility to targeted drugs.

Targeted therapy is central to treating non-small cell lung cancer (e.g., EGFR, ALK, ROS1 alterations), breast cancer (HER2-positive), colorectal cancer, melanoma (BRAF mutations), chronic myeloid leukaemia (BCR-ABL fusion), renal cell carcinoma, and gastrointestinal stromal tumours (KIT mutations).

Targeted drugs can be used alone or combined with chemotherapy, immunotherapy, or hormone therapy. When resistance mechanisms emerge over time, repeat biopsies often guide the selection of next-generation targeted agents tailored to secondary mutations.