Chemo is systemic poison timed against dividing cells
Chemotherapy floods the bloodstream with drugs that jam mitosis or damage DNA so repair pathways tip cells toward death. That systemic reach can hit cancer anywhere—and healthy fast-dividing tissue too—so regimens are staged as induction, consolidation, adjuvant, or purely palliative care.
Chemotherapy uses one or more anti-cancer drugs in a planned regimen, aiming to cure, lengthen life, or ease symptoms. Today's common meaning stresses nonspecific intracellular poisons that block cell division or injure DNA, distinct from selective signal-blocking targeted drugs. Because agents travel in the blood, they are systemic therapy and are often paired with local tools such as surgery or radiation. Cytotoxic drugs stress cells; if apoptosis follows, the tumor shrinks, but susceptibility varies widely among cancers.
Strategies have names that mark timing and intent. Induction is first-line treatment with curative aims. Consolidation repeats the successful drug after remission; intensification swaps in a different agent. Combination regimens use several mechanisms at once to limit resistance and allow lower individual doses. Neoadjuvant therapy shrinks tumors before surgery; adjuvant therapy follows local treatment to mop up micrometastases. Maintenance means repeated low doses to prolong remission; salvage or palliative courses trade cure for smaller tumor burden and gentler toxicity.
Only patients fit enough for the stress should receive full doses; performance status guides eligibility and reductions. Because each cycle kills only a fraction of tumor cells, repeated courses matter. Effectiveness spans cures in some leukemias, little benefit in certain brain tumors, and unnecessary use against most non-melanoma skin cancers. Side effects often mirror damage to other rapidly dividing cells—hence familiar hair, gut, and blood-count costs—even when the clinical goal is carefully chosen.
Source: Chemotherapy
