What Cancer Is and Why It Matters

This lesson introduces cancer as a disease of abnormal cell growth, survival, and spread. It explains why cancer is not one single illness, how normal controls on cell division can fail, and why early detection and accurate classification matter for treatment.

Learners will distinguish benign tumors from malignant cancers, understand the basic idea of metastasis, and recognize why cancer matters not only biologically but also clinically, socially, and personally. Later lessons will build on this foundation by examining cancer types, staging systems, diagnostic workups, and treatment choices in greater depth.