Cancer in its many forms is one of the most devastating diseases in our society, taking more than one thousand lives every day in the United States alone. In the US, cancer is the second most common cause of death after heart disease. While advances in medical technology have dramatically improved cancer survival rates, it still accounts for approximately 1 in every 4 deaths in industrialized nations.
Common types of cancer
Cancerous cells can develop anywhere in the body, but the most common types of cancer occur in the breast (mostly in women), prostate (men only) colon, skin, lung, lymphoma, urinary bladder, thyroid, kidney, pancreas, leukemia, and brain.
How do cancer cells form?
The most important thing to understand about cancer cells in humans and other animals is that the biochemistry underlying the development of malignant cancer cells is different for different types of cancer, which is why it is so difficult to find a cure for cancer – there is no one cure. Regardless of the mechanisms behind it, cancer cells are simply normal cells which have, for one reason or another, entered a stage of uncontrolled, unregulated growth. This rapid growth and division of cancer cells is what causes tumors to form and is the target of chemotherapy drugs.
Cell growth and division is controlled by specific genes in our DNA. When DNA is damaged, or if it contains risky forms (alleles) of these genes, the regulation of these cellular processes can go haywire and lead to cancer. This is why cancer can be caused by environmental exposures (UV rays, chemicals, radiation, tobacco smoke), genetic predisposition (inherited forms of genes linked to increased risk of certain cancers), or due to random mutations.
Cancer cells grow and divide unchecked, forming tumors. As the tumors grow, the malignant cells send signals to the body to form new blood vessels so that they get the oxygen and nutrients they need to continue growing and spreading in a process called angiogenesis. When cancer that has developed in one part of the body spreads to other parts, this is called metastasis. This may happen through the lymph system, the bloodstream, or to nearby organs through contact.
Cancer screening and treatment
Early detection is the most important factor to a good prognosis for cancer, which is why it’s important to follow doctors’ guidelines for routine testing according to your age and sex.
Once cancers have reached a certain stage, they become more difficult to treat and the side effects of treatment will be more serious. After the cancer has metastasized, treatment becomes even more complicated and chances of survival are dramatically reduced.