Cancer is a disease that begins in the cells of the body. In normal situations, the cells grow and divide as the body needs them. No more, no less. This orderly process is disturbed when new cells form that the body were not needed and old cells don't die when they should. These extra cells lump together to form a growth or tumor.

Understanding tumors
Two types of tumors exist, benign and malignant. Benign tumors are not cancerous. They can usually be removed and generally don't grow back once they're gone. The cells in benign tumors don't spread and it is rare for a benign tumor to be life-threatening.

Malignant tumors, on the other hand, are cancerous. The cells in them are abnormal and divide randomly and chaotically. The cells behave aggressively and attack the tissue around them. They also can jump away from the malignant tumor and enter the bloodstream or lymphatic system to form new tumors in other parts of the body. This type of spread is known as metastasis.

Types of cancer
There are virtually dozens of different cancer types. The most common in the US is a non-melanoma skin cancer. Close to one million new cases of it were reported in the US in 2005. Breast, lung and prostate cancer also are very common.

Effects of cancer
A cancer diagnosis permanently changes your life -- sometimes surprisingly for the better and other times with dire consequences. You are suddenly faced with hundreds of decisions, from choosing a doctor, to considering different treatments, to figuring out how you’re going to pay for it all.

Things can seem scary and overwhelming when you are first digesting the news. Urgent decisions need to be made quickly, and even as you are doing just that the cancer can be spreading throughout your body. While there is no lack of information about what to do and how to do it, wading through the mountain of research is an exhausting task.

That's why wikiCancer is here -- so that anyone touched by a cancer diagnosis can share their experience, find support, and get and give real answers to important questions quickly and easily.

A short history of cancer
Cancer is not a new disease. Written descriptions of it can be found on Egyptian papyrus dating back to roughly 1600 BC. The Egyptians blamed the disease on the gods and treated it with a cauterizing tool they called “the fire drill”. Apparently the drill did not work, as the writing on the papyrus says, “There is no treatment.”

The Greek physician Hippocrates is believed to be the first person to use the word “carcinos”, which describes the crab-like way that both the ulcer-forming and non-ulcer forming tumors spread. Over time, the word shortened to “cancer”.

When the first autopsy was performed by Italian anatomist Giovanni Morgagni in 1761, the foundation was laid for the scientific study of cancer, also known as oncology.

The 18th century John Hunter was one of the first people to suggest operating on a tumor. Unfortunately for his patients, anesthesia was not developed until a century later. Not surprisingly, surgery began to flourish once anesthesia was introduced.

When the modern microscope was invented in the 19th century, it allowed scientists to study cancer with the unaided eye and the modern pathologic study of cancer was born. Surgeons could now remove tissue and pass it to pathologists, who could tell the surgeon whether or not an operation successfully removed a tumor.

Cancer Q&A

What causes cancer?

DNA is found in every cell in the body and regulates all of its activities. Cancer is caused by damage to DNA. The body is usually able to repair damaged DNA, but is unable to do so in cancer cells.

Some people inherit damaged DNA, but in most cases people damage it themselves through lifestyle choices such as smoking, exposure to ultraviolet radiation (UV) from the sun or exposure to cancer-causing substances known as carcinogens in the environment, such as asbestos.

Inheriting damaged genes or being exposed to carcinogens does not mean that cancer is inevitable. It does, however, mean that the chance of getting cancer is increased. Scientists are still trying to understand the factors that can increase a person’s chance of developing cancer.

While being infected with certain viruses, such as the human papillomavirus (HPV) and human immunodeficiency virus (HIV), can increase the risk of some types of cancer, cancer is not contagious. You can't "catch" cancer from someone who has the disease. Scientists also know that an injury or bruise does not cause cancer.

Can cancer be prevented?
There are a number of ways to reduce the chance of getting cancer, including:

• Not using tobacco products
• Choosing foods low in fat
• Eating a diet rich in vegetables, fruits, and whole grains
• Exercising regularly
• Maintaining a healthy weight
• Avoiding over-exposure to the sun

Early detection is also a powerful way to prevent cancer, as treatment is often more effective when cancer is detected in its early stages. By getting regular checkups and screening exams, such as sigmoidoscopy, colonoscopy, mammography, and the Pap test; precancerous conditions can be detected and treated before they turn into cancer.

What are the symptoms of cancer?
Cancer can cause a variety of symptoms or none at all. Possible signs include:

• A thickening or lump in any part of the body
• Noticeable changes in a wart or mole
• A sore that does not heal
• A nagging cough or hoarseness
• Changes in bowel or bladder habits
• Indigestion or difficulty swallowing
• Unexplained changes in weight
• Unusual bleeding or discharge

Not all of these symptoms are caused by cancer. They can also be caused by infections, benign tumors, or other problems. Only a doctor can make a cancer diagnosis. Anyone with these symptoms should not wait to feel pain before seeing a doctor because cancer doesn't normally cause pain in its early stages.

What happens when a doctor suspects cancer?
A doctor may order various tests or recommend a biopsy. A biopsy is usually the most reliable way to know whether a medical problem is cancer.

During a biopsy, the doctor removes a sample of tissue from the abnormal area. A pathologist studies the tissue under a microscope to check for cancer cells.

How is cancer treated?
Conventional cancer treatment can include surgery, radiation, chemotherapy, hormone therapy, and biological therapy. The doctor may use one method or a combination of several, depending on the type and location of the cancer, whether the disease has spread, the patient’s age and general health, and other factors.

Some people choose to try complementary and alternative therapies as part of their cancer treatment. Some government-run organizations provide up-to-date information about various healing practices used in conjunction with cancer treatment.

Are there side effects to cancer treatment?
Because cancer treatment damages healthy cells and tissues as well as cancerous ones, it often causes side effects. Anyone about to receive cancer treatment should thoroughly talk to their doctor about all the treatment options, weighing the likely benefits of killing cancer cells against the risks of possible side effects.

Can conventional treatments make the cancer worse?
People sometimes worry that having a biopsy or surgery for cancer will spread the disease. This can happen, but only very rarely. Surgeons take special precautions to prevent the spread of cancer during surgery.

Are clinical trials a treatment option for cancer?
Participating in a clinical trial is a valid treatment option for people with cancer. Doctors conduct clinical trials to learn about the effectiveness and side effects of new treatments. Through research, doctors learn new ways to treat cancer that may be more effective than conventional cancer therapy.

Clinical trials follow strict guidelines and have procedures to protect the safety of the people who join the study. The information gained from the trials has led to significant advances in cancer treatment.

People who take part in the studies have a chance to benefit from treatments that have shown promise and make an important contribution to medical breakthroughs.

Is cancer painful?
Sometimes cancer is painful and other times it isn't. Whether a patient has pain depends on the type of cancer, the extent of the disease, and the individual's tolerance for pain. Pain usually occurs when the cancer grows and presses against bones, organs, and nerves. Pain can also be a side effect of cancer treatment.

Pain should not be accepted as a normal part of having cancer. It is important for people to talk about their pain so steps can be taken to help relieve it.

What are some ways to relieve pain?
Doctors can prescribe medicines or recommend over-the-counter drugs to relieve pain. Some people fear become addicted to pain medication, but the fact is that addiction to prescribed cancer pain medicines is somewhat rare.

If you take pain medication and start to feel uncomfortable side effects, talk to your doctor about changing the dose or type of medication.

See also

• Just diagnosed?
• Cancer Types
• Conventional treatment options
• Financial issues