Cancer in disguise
What is cancer?
Cancer is an uncontrolled proliferation of certain abnormal cell types in the body that invade surrounding normal tissue. The cell type and location determine the type of cancer. Cancers can be found in solid tissue or in tissues of the bone marrow, blood or lymph tissues. Cancer does its damage to the host by growing rapidly and robbing normal cells of nutrients. Additionally, cancer can spread to other areas, a process called metastasis. Cancers can cause secondary problems by obstructing organs, eroding tissue, causing swelling or seizures when found in the brain, or preventing the normal development of different types of blood cells.Common forms of cancer
The most common form of cancer in the U.S. for both men and women, is non-melanoma skin cancer, with about 700,000 new cases annually. The majority of these are basal cell carcinomas (80%), while the remainder are predominantly squamous cell carcinomas. Cumulative exposure to ultraviolet sunlight radiation is the principal risk factor associated with this form of cancer. Fortunately, such cancers are amenable to surgical treatment, with relatively high success rates.Each year about 1.3 million new cases of other cancers (besides non-melanoma skin cancers) are diagnosed in the U.S. The most common of these in men are prostate, lung, colon, bladder, and rectal cancer. For women, the most common new cancers in order of decreasing frequency, are breast, lung, colon, uterine, and ovarian cancers. If ordered according to the cancers that cause the most deaths, the lists change slightly because some cancers have a greater potential for response to treatment than others. When forms of cancers are viewed in this manner, the top three most lethal cancers for men remain the same: lung, prostate, and colon, but pancreatic and stomach cancers now appear as fourth and fifth on the list. For women, the most common causes of cancer deaths are due to lung, breast, colon, ovarian, and pancreatic cancers, in that order.
