What Is Cancer?
Cells are building blocks in our bodies, which are tiny structures not visible to the naked eye. Groups of cells form tissues and organs of the body. They are produced by the division of other cells in a regular, controlled fashion. Our bodies constantly make new cells: to help us grow, to replace worn-out cells, or to heal damaged cells after an injury. Sometimes this control goes wrong and the cells divide in uncontrollably. This abnormal and excessive growth of tissue cells is cancer (also called a tumour). A tumour can be benign (not cancer) or malignant (cancer). A cancerous tumour is malignant, meaning it can grow and spread to other parts of the body. A benign tumour means the tumour can grow but will not spread.
Within each cell are thousands of genes that act as a command centre for the cell. Genes provide instructions for what role the cell will play in the body. The process of cell division and the passing along of genes to newer cells is usually well controlled, ensuring that the right kinds and numbers of cells are present for the different parts of the body to function correctly. The body and the cells can usually recognize when something has changed in a cell and will work to repair or destroy the abnormal cell. For cancer to start, certain changes take place within the genes of a cell or a group of cells. The change is called a mutation. It means that a gene has been damaged, lost or copied twice. Mutations also can happen by chance when a cell is dividing. Some mutations mean that the cell no longer understands its instructions and starts to grow out of control.
How Common Is Cancer Around The World?
According to the international agency for research on cancer, GLOBOCAN, 2018 saw 18.1 million new cases of cancer and about 9.6 million deaths globally. In Nigeria, there were 115950 new cases of cancer in 2018 with 70327 deaths attributed to cancer in the same year.
How Does Cancer Spread?
Cancerous tumours are malignant, which means they can spread into nearby tissues. As these tumours grow, some cancer cells can break off and travel through the blood or the lymph system to other places in the body to form new tumours, far from the original tumour. Unlike malignant tumours, benign tumours (non-cancerous) do not spread into nearby tissues and usually grow quite slowly.
The place where cancer starts in the body is called primary cancer or primary site. If cancer cells spread to another part of the body the new area of cancer is called secondary cancer or a metastasis. Cancer cells can travel in blood, lymph or spread from one organ to another ? if they are in direct contact. The process by which cancer cells spread to other parts of the body is called metastasis.