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Cancer What is Cancer? Group of diseases characterized by new cells that divide and grow unrestrained. Johannes Muller discovered that tumors were made up of cells. Neoplasm: “New growth.” Neoplastic growths rob nutrients and provide no benefit to the organism Ovarian Cancer Cell
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What is Cancer? • Group of diseases characterized by new cells that divide and grow unrestrained. • Johannes Muller discovered that tumors were made up of cells. • Neoplasm: “New growth.” Neoplastic growths rob nutrients and provide no benefit to the organism Ovarian Cancer Cell
Four Types of Malignant Growth • Carcinoma- Epithelial tissue cancers. Smooth linings of inner & outer surfaces of body. • Sarcoma- Connective tissue involvement, bone, cartilage, and muscle. • Leukemia- Cancers arising in the blood, stem cells in bone marrow. • Lymphoma- Cancer of the lymphatic system. • Carcinomas account for about 85% of all cancers. Another 10% are Sarcomas and Leukemias. • Carcinoma rates increase with age. Sarcoma, which accounts for about 2% of cancers, has a constant rate across the lifespan
Carcinoma • Risk increases with age, probably due to cumulative effects of exposure to environmental carcinogens.
Types of Neoplasms • Benign: Remain localized, in one place. • Malignant: tend to spread, or metastasize, and establish secondary colonies. They destroy surrounding tissue • Cells seem to be limited to about 50 divisions in a lifetime. Cancer cell have no such limits and become like a parasite.
Metastasis • Refers to the ability of cancers to spread via the blood and lymph systems. • New cell colonies established at sites distant from the original tumor.
Metastasis Growth of Tumor Vascularization Invasion Attachment to endothelium Transport Interaction with Vascular Components Retraction Underlapping Overlapping Invasion through Basement Membrane Establishment of Micrometastases
Skin Cancers • Melanoma – Most dangerous form of skin cancer because it metastasizes. Cancer arising in the Melanin, or skin pigment. • A = Asymmetry • B = Border Irregularity • C = Color Variation • D = Diameter > 6 mm, or about the size of a pencil eraser Maureen Reagan died of metastatic melanoma (brain and bone involvement) in 2001 at age 60.
Basal and Squamous Cell Carcinomas • Basal cell carcinoma affects 800,000 Americans each year. It is the most common of all cancers • Squamous cell carcinoma, the second most common skin cancer, afflicts more than 200,000 Americans each year. Squamous cell cancers may occur on all areas of the body including mucous membranes. • Both are most common in areas exposed to the sun Basal Cell Carcinoma Squamous Cell Carcinoma
Kaposi’s Sarcoma • Rare form of skin cancer, but not uncommon among AIDS patients. • May be fatal if lungs or other internal organs are affected.
Breast Cancer 7 cents from the sale of each stamp went to fund breast cancer research
Prostate Cancer Prostate Anatomy
Prostate Cancer Stage A : Deep tumor. May not be detected by digital-rectal exam Stage B: Tumor may be detected by DRE or ultrasound Stage D: Metastasis to bone and lymph nodes Stage C: Spread to surrounding tissue
Eric Davis • In June 1997, at age 34, he underwent surgery to remove a baseball-sized colorectal cancer tumor. By September he was back in the line-up.
Screening for Colon Cancer • British advertising campaign to prompt screening for colon cancer.
Brain Cancer Glioma, or cancer arising in the glial cells of the brain. Note its position inside a ventricle.
Brain Cancer MRI showing no tumor (left) and three months later (right)
Behavioral Risk Factors • Smoking • Diet • Alcohol • Exercise • Ultraviolet Light • Sexual Behavior
Smoking • Primary cause of preventable death in the U.S. (400,000/year) • About 90% of lung cancer cases are smoking related (80% in women). • Smoking is also related to other forms of cancer (e.g, bladder, pancreas, leukemia). • Relative risk of lung cancer is about 9 times greater in smokers than in nonsmokers. • Smokers tend to show and “optimistic bias” and underestimate the risks associated with smoking.
Safe Smoking? • Cigars and Pipes carry relative risks of 2.9 and 2.5, respectively for lung cancer. Lower than for cigarettes, but still considered moderate. • Cigars + Cigarettes – RR= 6.9 • Pipes + Cigarettes – RR= 8.1
Alcohol • Alcohol implicated in cancers of tonsils, tongue, pancreas, and liver. • Alcoholism associated with cirrhosis of the liver, and cirrhotic livers more prone to cancer. • Liver cancer is not a leading cause of death among alcoholics, however. • Alcohol interacts with smoking to increase risk of laryngeal cancer.
Ultraviolet Light • Sun exposure, fair skin, and not using sunscreen are risk factors for skin cancer. • Lifetime exposure and occasional severe sunburn increase risk of skin cancer. • Wear sunscreen and protective clothing. Young, white men with no skin cancer history are the least likely to take precautions Malignant melanoma is a form of skin cancer that can be fatal. Other forms generally don’t contribute to cancer mortality.
Sexual Behavior • Kaposi’s Sarcoma and Non-Hodgkin’s Lymphoma are related to AIDS. • Invasive cervical cancer risk factors: 1. Multiple partners 2. Low SES 3. Early 1st sexual experience 4. Early pregnancies 5. Male sex partners who have had multiple partners
Environmental Risk Factors • Radiation • Asbestos • Pesticides • Benzene • Nickel • Vinyl Chloride • Some Petroleum Products
Environmental Risk Factors: Evidence • Nuclear power plant workers:cancer death rates increase with increased radiation exposure (men only). • Also, death rates from cardiovascular disease (men and women) and accidents (men only) increased. • Radiation exposure contributes to all-cause mortality in these workers Living near a nuclear power plant does not increase cancer risk.
Power Lines • No evidence that living near power lines increases cancer risk. • Occupational exposure to magnetic fields also unrelated to cancer risk.
Aspartame • No evidence that Aspartame (Nutrasweet) is related to brain cancer. • Aspartame is metabolized to aspartic acid, phenylalanine, and methanol, which occur naturally in larger quantities in many other foods. • Because it breaks down into these components before absorption, it has no opportunity to affect organs.
Inherent Risk Factors • Family History • Ethnic Background • Age
Psychological Risk Factors • Depression – no clear relationship to cancer. No relationship between depression and incidence of cancer and no evidence of a causal relationship
Suppression of Emotion • No evidence of a “cancer-prone,” or “Type C” personality. • Suppression of emotion shows a consistent relationship with cancer incidence.
30-year Prospective Follow-up Study of Emotional Suppression and Cancer Incidence 1% Cancer Incidence “Acting Out” Shaffer, J.W., Graves, P.L., Swank, R.T., & Pearson, T.A. (1987). Clustering of personality traits in youth and subsequent development of cancer among physicians. Journal of Behavioral Medicine, 10, 441-447. Loners & Emotional Suppression 16% Cancer Incidence 30 years later Beginning of Study
Cancer Survival and Psychosocial Factors • Cancer patients who are depressed, anxious, guilty, and alienated live longer than hopeless/helpless patients. “Fighting Spirit.” • Married cancer patients live longer than unmarried cancer patients, even when controlling for early diagnosis and treatment among married patients. • Married patients have a greater degree of social support and more extensive social networks. These provide: 1. Access to information 2. Sense of personal control 3. Self Esteem 4. Optimism
Psychotherapy and Survival • Psychotherapy can help alleviate stress and increase sense of well-being. • The ability of psychotherapy to extend survival time is less well-established. • Speigel, et.al, (1989) found that women with metastatic breast cancer lived about 18 months longer if they received weekly, 90-minute, support group meetings, compared to women who received only medical treatment. Assignment to treatment conditions was random.
Psychotherapy and Survival • Review of literature on psychotherapy and cancer survival was less impressive. Some studies were able to show a benefit, some were not. • Studies that showed a benefit for psychotherapy had the following components: 1. Social support 2. Group therapy with patients who have the same cancer 3. An educational component 4. Training in coping strategies