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Cancer Basics

Cancer isn't just one disease. It is a large and complex family of malignancies that can affect virtually every organ in the body. Cancer is second only to heart disease as the leading cause of death in the United States. Over 1.2 million new cases are diagnosed every year, with half of them occurring in the lung, prostate, breast, colon and rectum. Cancer can strike at any age, although it is most common in people over 50.

Cancer begins in the body's cells, which are constantly dividing and multiplying to replace old, damaged cells. Sometimes, cells begin to divide unnecessarily, forming excess tissue known as a tumor. In most cases, tumors are benign, meaning that they are not cancerous. Benign tumors, although they may cause some health problems depending on their size and location, are not life-threatening.

However, if an abnormal cell begins to divide, it eventually forms a malignant, or cancerous tumor. Most malignant tumors grow quite rapidly, invading nearby organs and tissues. Cancerous cells can also travel through the bloodstream to other regions of the body. When cancer spreads from its original site, the process is known as metastasis.

The good news is that cancer death rates have been declining in recent years, especially among men, who generally experience higher rates than women. Increasing public awareness has resulted in more people getting regular cancer screenings, and practicing healthy lifestyles to reduce their risk.

Causes of Cancer

The vast majority of cancers--about 80%--are considered sporadic, meaning that there is no clear cause. For some reason, certain normal genes begin to mutate (change), multiplying rapidly and becoming malignant. There are several environmental influences that may cause these gene mutations to occur. In fact, a large number of cancers are preventable because most of these factors can be controlled with healthy lifestyle choices.

    Environmental causes of cancer include:
  • Age: cancer is most common among people over the age of 50.
  • Diet: high-fat, high-cholesterol diets are proven risk factors for several types of cancer, particularly colon cancer
  • Obesity: although no clear link has been established, research indicates obesity may be a contributing factor to some cancers.
  • Cigarettes greatly increase the lung cancer risk, even among non-smokers forced to inhale secondhand smoke. Other tobacco products, like pipes and chewing tobacco, are linked to cancers of the mouth, tongue and throat.
  • Long-term exposure to chemicals like asbestos, radon and benzene
  • Exposure to high levels of radiation
  • Harmful ultraviolet rays from the sun are directly linked to melanoma and other forms of skin cancer
  • Some viruses, including hepatitis B and C, human papillomaviruses (HPV), and the Epstein-Barr virus, which causes infectious mononucleosis, have been associated with increased cancer risk
  • Immune system diseases, like AIDS, can make one more susceptible to some cancers

The other 20% of cancers are hereditary. This means that the abnormal gene responsible for causing the cancer is passed from parent to child, posing a greater risk for that type of cancer in all descendants of the family. However, just because someone has a cancer-causing gene doesn't mean they will automatically get cancer. If hereditary cancer is suspected, family members should consider genetic counseling and testing to determine their risk. Regular cancer screenings are recommended for high-risk families so that if cancer does occur, it will be diagnosed in the early stages, when it's most responsive to treatment.

    Signs of hereditary cancer include:
  • Several relatives with cancer
  • Cancers that occur at an earlier age than normal
  • Multiple or bilateral cancers: for example, a person with breast cancer who also develops ovarian cancer
  • Rare or unusual types of cancer
  • Ethnic background: some cancers are more common among certain population groups

7 Warning Signs of Cancer

Unfortunately, many types of cancer don't display any obvious symptoms or cause pain until well advanced. Because early-stage cancer symptoms tend to be subtle, they are often mistaken for signs of other, less-threatening diseases. Here are the seven warning signs of cancer:

  • Changes in bowel or bladder habits
  • A sore that does not heal
  • Unusual bleeding or discharge
  • Thickening or lump in the breast or any other part of the body
  • Indigestion or difficulty swallowing
  • An obvious change in a wart or mole
  • A nagging cough or hoarseness

Some symptoms are specific to certain types of cancer, such as difficult urination for prostate cancer, or flu-like symptoms for acute leukemias. Don't be afraid to discuss unusual symptoms with your doctor! Diagnostic tests are available for most common cancers. If diagnosed early, your chances of surviving cancer are greatly increased.

Initial Diagnosis

There is a wide array of methods to diagnose cancer. As researchers learn more about the mechanisms of cancer, new diagnostic tools are constantly being developed and existing methods refined. If your primary care physician suspects cancer, he or she may order some tests to confirm the diagnosis. These tests can either be conducted by your physician or by oncologists at cancer centers like Nazha Cancer Center. No matter who makes the diagnosis, a second opinion by a cancer expert is strongly recommended. Some types of cancer, particularly lymphomas, can be hard to classify, even for an expert. Accurate identification of cancer allows oncologists to choose the most effective treatment. The most common diagnostic methods include:

  • Biopsy: a small tissue sample is surgically removed and examined under a microscope for the presence of cancer cells. Depending on tumor location, some biopsies can be done on an outpatient basis with only local anesthesia. If the tumor is filled with fluid, a type of biopsy known as a fine needle aspiration is used. A long, thin needle is inserted directly into the suspicious area to draw out fluid samples for examination.
  • Endoscopy: a flexible plastic tube with a tiny camera on the end is inserted into body cavities and organs, allowing the physician to view the suspicious area. There are many types of scopes, each designed to view particular areas of the body. For instance, a colonoscope is used to detect growths inside the colon, and a laparoscope is used to examine the abdominal cavity.
  • Diagnostic imaging: several techniques are used to produce an internal picture of the body and its structures. Types of imaging methods include:
    • X-rays are the most common way doctors make pictures of the inside of the body. Specialists can spot abnormal areas that may indicate the presence of cancer.
    • CAT scan (computerized axial tomography), uses radiographic beams to create detailed computerized pictures taken with a specialized X-ray machine. It is more precise than a standard X-ray, and provides a clearer image.
      • Magnetic Resonance Imaging (MRI) uses a powerful magnetic field to create detailed computer images of the body's soft tissue, large blood vessels and major organs. MRI is an accurate but expensive process, and patients must lie completely still during the procedure for best results.
      • Ultrasound uses high-frequency sound waves to determine if a suspicious lump is solid or fluid. These sound waves are transmitted into the body and converted into a computerized image.
  • Blood tests: some tumors release substances called tumor markers, which can be detected in the blood. A blood test for prostate cancer determines the amount of prostate specific antigen (PSA). Higher than normal PSA levels can indicate cancer. Recently, a blood test for ovarian cancer, known as CA-125, has become available. However, blood tests by themselves can be inconclusive, and other methods should be used to confirm the diagnosis.

Preventing Cancer

Up to 85% of cancers can be prevented by avoiding environmental risk factors like smoking, sun exposure, alcohol abuse and poor nutrition. Of course, things like age, race, gender and family history cannot be changed, but knowing your personal cancer risk can help you devise a prevention strategy with regular screenings and healthy lifestyle choices. Having one or more risk factors for cancer doesn't mean you will get cancer. In fact, many people considered high-risk never develop cancer while others with no known risk factors become ill.

Nazha Cancer Center can help you with risk assessment, cancer screening, genetic testing and other services, including information on nutrition and smoking cessation. Follow the road to cancer prevention by taking charge of your health.