What is Cancer?
Cancer is a large group of diseases characterized by:
• Abnormal cell structure
• Uncontrolled growth
• Ability to spread
• Ability to invade normal tissue
• Cancer is a group of more than 100 different kinds of diseases.
Cancer occurs when abnormal cells in the body keep dividing and forming more cells without control.
Cancer is the second leading cause of death today. At the beginning of the 20th century, cancer was the eighth leading cause of death in this country. One in four deaths in the United States is caused by cancer. Due to changes in lifestyle behaviors, there has been an increase in certain cancers. However, with improvements in public/professional education, primary prevention, early detection and treatment, the incidence and mortality rates are declining.
Classification of Cancer
Tumors can be classified as benign or malignant. The word tumor comes from the Latin word tumure, meaning “to swell.” Its meaning is often used synonymously with the term “neoplasm.” Neoplasm refers to an abnormal growth of tissue whose cells usually have rapid growth.
Benign tumors are non-cancerous and considered harmless. However, a benign tumor can lead to death if it grows in a critical area of the body such as the brain. Benign tumors may turn into malignant tumors.
Malignant tumors have the property of invading surrounding tissue, destructive growth, and have the ability to spread to lymph nodes and other parts of the body (metastasize).Tumor Staging is performed to determine the extent of the disease. The TNM classification system is commonly used to stage many cancers. T=primary tumor size, N=nodal involvement, and M=presence or absence or metastases.
Causes of Cancers
The exact cause or causes of most cancers are unknown, except for lung cancer.
• Cigarette smoking is the major contributor of lung cancer. Therefore, lung cancer can usually be prevented. It has also been implicated in the risk of developing bladder cancer, the exact mechanism is not known, but statistics show that there is a correlation. Smokers run a higher risk of developing lung cancer than non-smokers. Smoking related illnesses cause about 385,000 premature deaths every year.
• Environmental factors may be involved in a significant percentage of cancers. Parasite-Schistosoma haematobium, in some parts of the world (Egypt) can cause bladder cancer. It invades the body then migrates to the bladder.
• Industrial environment with some occupations have been implicated in the etiology of some cancers. People who work with asbestos or in mines are at high risk of developing lung cancer. Asbestos workers may develop mesotheliomas of the pleural or peritoneal cavities. Exposure to certain solvents, (benzene) has been associated with an incidence of leukemia.
• Ultraviolet light and irradiation is responsible for high incidence of skin cancer as a result of exposure to excessive sunlight. An increased incidence of leukemia has been reported after exposure to radiation.
• Diet influences cancer development. It is suspected that colorectal cancer is due in part to the Western diet, which consists mostly of processed foods with less consumption of roughage, bulk, and non-digestible complex carbohydrates. A non-Western diet is high in fiber and has a low incidence of colorectal cancer but a high incidence of stomach cancer. A high fiber diet moves through the intestine faster and produces a large soft stool that is easy to excrete. A low fiber diet may produce the reverse effect.
• Late first full-term pregnancy over age 40; having a first menstrual period at an early age, late menopause; and a familial history of breast cancer may be a contributor towards breast cancer.
• Sexual activity at an early age and having multiple partners, or exposure to the human papilloma virus may cause cervical cancers.
• Age and race are significant risk factors. The elderly and African Americans are at a much higher risk for Prostate Cancer. White men between the ages of 20 and 40 are at the highest risk for Testicular Cancer.
Early Warning Signals of Cancer
The best opportunity for curing cancer is early detection followed by appropriate treatment. The American Cancer Society has compiled a list of seven early warning signals.
• Change in bowel or bladder habits may signal a sign of colorectal cancer. Constipation or diarrhea alone or alternating with each other. If accompanied by abdominal pain, it may indicate partial obstruction of the colon. The main symptom in cancer of the rectum is blood in the stool.
• A sore that bleeds easily or does not heal may be due to cancer. Oral cancer for example may be due to heavy smoking, drinking, or the use of chewing tobacco. Chewing tobacco can cause white, roughened patches to form in the mouth.
• Unusual bleeding or discharge from the rectum may be a sign of colorectal cancer or if it is from the vagina it may be a warning sign of uterine cancer. Vaginal bleeding is unusual when it occurs between regular menstrual periods or after menopause. Bladder or kidney cancer may be manifested by blood in the urine or by difficult or painful urination.
• A thickening or lump in the breast or elsewhere may be an indication of breast cancer or it may indicate nonmalignant cystic masses. Other signs of breast cancer include retraction of the nipple, nipple discharge or pain and tenderness. Testicular cancer can be felt as a lump. Enlarged lymph nodes, especially in the neck, may be an early sign of lymphoma.
• Indigestion or difficulty in swallowing (dysphagia) can be a symptom of esophageal or stomach cancer. Dysphagia may be due to physical obstruction, such as malignancy, or a motor disorder.
• An obvious change in a mole or wart or darkening of a previously normal area is often a sign of skin cancer. Most skin malignancies are easily curable; however, malignant melanoma can metastasize very quickly, so early detection is very important. This cancer is associated with a small, black lesion, which may be raised and may not always appear on sun-exposed areas.
• A nagging cough or hoarseness can be lung cancer. It is the leading cancer killer in men and women.
Warning Signs of Other Cancers
Ovarian cancer may be “silent,” but it is usually associated with abdominal swelling and occasional pain that is often confused with stomach discomfort, distention, or gas. Vaginal bleeding is rare.
Oral cancer may stem from a sore that bleeds easily and does not heal. Pain may or may not be present when swallowing or chewing. Pre-cancerous lesions have a white, patchy appearance.
Prostate cancer symptoms are the same as for benign prostate hypertrophy (urinary frequency and hesitancy). More ominous symptoms include lowerback pain and blood in the urine.
Bladder cancer may be associated with increased urinary frequency. A common symptom is blood in the urine.
Skin cancer lesions may appear scaly and can ooze blood or blood-tinged serum. There may also be changes in sensation, tenderness or pain. Melanoma signs include a raised dark bump with pigment spreading beyond the edge.
Leukemia is often diagnosed on patients experiencing repeated infections, fatigue, paleness and weight loss. Frequent nosebleeds may also occur and symptoms tend to appear rapidly in children.
Screening for Cancer
The American Cancer Society Recommendations for the Early Detection of Cancer in Average-Risk, Asymptomatic people:
Diet, exercise, reducing exposure to environmental risks, and reducing or not smoking will greatly improve your health. Combined with early screening and detection, prompt treatment can be performed which will improve your chances for a better outcome.
Avoid obesity. Individuals who are 40% or more overweight increase their risk for certain types of cancers.
Reduce total fat consumption. A high fat diet may be a factor in the development of particular cancers. Eat more high-fiber foods such as whole grain cereals, fruits and vegetables. Studies suggest that a high-fiber diet may help to reduce the risk of colon cancer.
Include foods rich in vitamins A and C daily such as dark green, deep yellow vegetables and fruits: spinach, carrots, and apricots. Vitamin C can be found in oranges, grapefruits, strawberries, green and red bell peppers.
Include cruciferous vegetables in your diet regularly - e.g. cabbage, broccoli, Brussels sprouts, cauliflower.
Minimize consumption of smoked, salt-cured, and nitrite-cured foods such as cold cuts and canned meats.
Keep alcohol consumption moderate - it may play a role in the etiology of liver cancer.
Knowing the stage of the cancer is very important for planning treatment. The plan of care may be curative or palliative depending on the stage of the disease, its location in the body, which symptoms are present, and the general health and age of the patient. Treatment may include:
• Radiation therapy, which involves the use of high-energy rays to damage cancer cells and stop their growth.
• Chemotherapy, which involves the use of drugs to kill cancer cells. The drugs can be in the form of pills, administered intravenously (IV), or injected directly into a vein, muscle or fatty tissue. Chemotherapy is usually administered in cycles, a treatment period followed by a rest period.
• Surgery is another option if the lesion is small and has not spread to other healthy tissues.
• Biotherapy/Immunotherapy is another alternative that involves the use of the body’s own immune system to fight the cancer cells. One or a combination of therapies may be implemented in the treatment plan depending upon the physician’s recommendation.
Side Effects of Treatments
Many anticancer drugs are made to destroy or control the rapidly growing cancer cells. Unfortunately, the drugs can also affect rapidly growing healthy cells. The damage to normal cells can cause side effects such as hair loss, vomiting, nausea, mouth sores, taste changes, skin changes, fatigue, a lower white blood cell count and potential for bleeding.
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A Cancer Journal for Clinicians, January/February 1998. Vol. 48, No. 1.
A Cancer Journal for Clinicians, January/February 2000. Vol. 50, No. 1.
Please talk to your physician if you have questions about your health and if you would like to know more about cancer.