Cancer is caused by abnormal cell growth. Normal cells reproduce and develop only when and where they are needed (e.g. in tissues or structures that are still developing in growing kids, to replace damaged, killed or worn out cells, etc.). When cells grow or multiply out of control, a tumor (lump) is formed. Tumors can be malignant or benign. A benign tumor is not cancerous, rarely comes back when removed and do not spread to other parts of the body. Malignant tumors, on the other hand, are cancerous and spread to other parts of the body (called metastasis).
A normal cell becomes cancerous when there is a change in the cell’s genetic material, which can occur spontaneously or is brought by carcinogens (an agent that causes cancer) such as chemicals, tobacco, viruses, radiation, etc. Even when a normal cell becomes cancerous, the immune system can often recognize it and remove it before it replicates or spreads. Thus cancer is more likely to progress in people whose immune system is somehow compromised.
There are more than 100 different known cancer types. Symptoms and treatment depend on the cancer type and how advanced it is. Treatment plans may include surgery, radiation and/or chemotherapy. Sometimes alternative medical methods are employed to mitigate the suffering of cancer patients caused by the traditional treatment methods.