Principles

How Cancer Drugs Work: The Cell Cycle, Log-Kill and Why We Combine Them

Cancer is one idea gone wrong: a cell that divides when it should not, and refuses to die. Almost every classical cancer drug is a counter-move to that single idea — it attacks cells while they divide. But that strategy carries three hard truths with it: each dose kills a fraction, not a number; one drug is rarely enough; and the poison cannot tell a tumour cell from your gut lining. Understand those three and the whole rhythm of chemotherapy — the cycles, the combinations, the toxicities — stops looking like a mystery and starts looking like arithmetic.

Chemotherapy Toxicity and Dosing: The Narrow Line Between Help and Harm

Cytotoxic chemotherapy has no address of its own. It kills what divides fast — and cancer is not the only thing dividing fast inside you. The same drug that shrinks a tumour also strips the bone marrow, the gut lining, the hair, the gonads. So the whole craft of oncology is a balancing act on a very narrow ledge: enough to hurt the cancer, not so much that you kill the patient. Learn the predictable toxicities, the nadir, and the maths behind mg/m² and AUC, and chemo stops being frightening and becomes something you can anticipate.