Understanding Cancer

What Is Cancer?

Cancer is generally defined as the unregulated growth of certain cells in the body. The word cancer actually refers to over 100 different diseases, but in all cases, certain body cells multiply in an abnormal, unregulated manner.

Normally, the growth and reproduction of every cell in the body are regulated. This regulation determines how the tissues and organs in the body function, as well as their size. When previously healthy cells in the body begin to grow too rapidly, they become abnormal and build up to form a solid mass, or tumor.

Types of Tumors

If the cells of the tumor remain localized at the site where they began in the body and multiply relatively slowly, the tumor is called benign. Benign tumors, such as cysts, warts, moles, and polyps, do not spread to other parts of the body. Benign tumors usually can be removed surgically and generally are not life threatening. Benign tumors won't return if all of the abnormal cells are removed.

Malignant tumors contain cells that grow rapidly and spread to healthy, normal bodily tissue. There are many altered properties of malignant cells that allow a pathologist—a physician who specializes in the causes of diseases—to determine if a tumor is abnormal.

What Is Metastasis?

The cells of malignant tumors may undergo metastasis, a process in which cells travel from their original tumor, and spread to other organs. Once this occurs, malignant cells develop into new tumors that often grow more rapidly than cells from the original tumor.

Complications from Cancer

The bone is a common site of metastasis for a number of different cancers.

Cancer cells that have metastasized to the bone can damage the bone, which can give rise to a variety of symptoms. Various treatments are available to control the symptoms and the destruction of bone.

Hypercalcemia of malignancy—an abnormal amount of calcium in the blood—is another possible complication from cancer. It affects approximately 10% to 20% of all adult patients at some point during the course of their disease.

How Is Cancer Classified?

Cancers are classified based on where they start growing. The four major categories of cancers include: carcinomas, sarcomas, leukemias, and lymphomas. About half of all cancers originate in one of 4 organs: the lung, breast, prostate, or colon.

How Cancers Start

Before a cell can become cancerous, its genetic information, or DNA, must be damaged. This damage is what causes a cell to grow rapidly and turn into a tumor. Not all cells will experience equal damage to their genetic material, and it is not possible to predict when cancer will spread or where it will go. This is why some cancers can spread so fast and aggressively, while other cancers are slow moving and treatable.

What Are the Stages of Cancer?

• In stage I, cancer cells can be distinguished from normal cells. The cancer cells are still localized (usually referred to as cancer in situ) and surgical removal of the tumor usually results in a cure.
• In stage II, tumor size is increased. The cancer cells may or may not have spread to the lymph nodes, and begun encroaching on nearby tissue.
• By stage III, the cancer cells have continued to grow and extend into the area around the tumor.
• In stage IV, tumors have spread to other parts of the body.

Symptoms Suspicious of Cancer

In its early stages, cancer typically does not have any symptoms. However, here are some important symptoms that might indicate the presence of cancer and should be brought to the attention of a doctor:

• Any changes in bowel habits. Suddenly developing constipation that continues for two weeks or more, especially if it's accompanied by intermittent attacks of diarrhea. Cancer of the bowel often presents itself in this way. Blood in the stool, even if attributed to hemorrhoids, should also be checked out because hemorrhoids can coexist with more serious colon problems. Finally, if normally bulky stool has become thin and ribbonlike, the reduced caliber may be due to a growth that's narrowing a portion of the colon.
• An open sore or a persistent rash that does not clear up may reflect skin cancer.
• Blood or discharge from any body orifice—vomited, coughed up, in the urine, from the vagina, or in the stool.
• Any persistent bump or lump anywhere—in the breast, on the skin, in the testicle, under the arms, neck, groin, or abdomen.
• Pain in the stomach, either when hungry or after eating, indigestion, or difficulty swallowing.
• A chronic, nagging cough, with or without sputum and especially (but not necessarily) accompanied by any amount of blood, however small, is a sign—especially in smokers. So is persistent hoarseness.
• A low-grade fever without an obvious cause (doctors called it FUO—fever of unknown origin) that continues for longer than a week or two warrants a visit to your doctor. It may be due to something as innocuous as an infection behind a tooth, but it may also reflect a serious process such as a diseased heart valve, an abscess somewhere in the body—or a hidden malignancy.
• Weight loss for no apparent reason. The problem may be due to a medication, an overactive thyroid, an undiagnosed infection—or, again, a hidden cancer.

Although these signs may be symptoms of other conditions, they should not be ignored because they are not causing any pain. Cancers often don't hurt in the early stages.

The information provided here does not substitute for the information or advice from a health care professional.