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CANCER

CANCER

What Is Cancer?

ØCancer – a large group of diseases characterized by the uncontrolled growth and spread of abnormal cells
Neoplasm – new growth of tissue that serves no physiological function
Tumor – clumping of neoplasmic cells
Malignant - cancerous
Benign - noncancerous
Biopsy – microscopic examination of cell development

ØMetastasis – malignant tumors that are not enclosed in a protective capsule have the ability to spread to other organs
Mutant cells – disruption of RNA and DNA within normal cells may produce cells that differ in form, quality and function from the normal cell

•Cancerous cells divide repeatedly out of control even though they are not needed, they crowd out other normal cells and function abnormally. They can also destroy the correct functioning of major organs.

What Causes Cancer?

 

•Cancer arises from the mutation of a normal gene.

•Mutated genes that cause cancer are called oncogenes.

•It is thought that several mutations need to occur to give rise to cancer

•Cells that are old or not functioning properly normally self destruct and are replaced by new cells.

•However, cancerous cells do not self destruct and continue to divide rapidly producing millions of new cancerous cells.

 

•A factor which brings about a mutation is called a mutagen.

 

•A mutagen is mutagenic.

 

•Any agent that causes cancer is called a carcinogen and is described as carcinogenic.

 

So some mutagens are carcinogenic

Eternalnal Factors – chemicals, radiation, viruses, and lifestyle

Internal Factors – hormones, immune conditions, and inherited mutations
Theories
•Cellular change/mutation theories
•Carcinogens
•Oncogenes/ protooncogenes

Risks For Cancer

Lifetime risk – the probability that an individual, over the course of a lifetime, will develop cancer or die from it
Relative risk – measure of the strength of the relationship between risk factors and a particular cancer
Smoking – 30% of all cancer deaths, 87% of lung cancer deaths
Obesity – 50% higher risk for breast cancer in postmenopausal women, 40% higher risk in colon cancer for men

Biological Factors

ØSome cancers such as breast, stomach, colon, prostate, uterus, ovaries and lung appear to run in families
Hodgkin’s disease and certain leukemia's show similar patterns
University of Utah research suggests that a gene for breast cancer exists
A rare form of eye cancer appears to be transmitted genetically from mother to child

Reproductive And Hormonal Risks For Cancer

Pregnancy and oral contraceptives increase a woman’s chances of breast cancer
Late menarche, early menopause, early first childbirth, having many children have been shown to reduce risk of breast cancer

Occupational And Environmental Factors

Asbestos
Nickel
Chromate
Benzene
Arsenic
Radioactive substances
Cool tars
Herbicides/pesticides

Social And Psychological Factors

Stress has been implicated in increased susceptibility to several types of cancers
Sleep disturbances, diet, or a combination of factors may weaken the body’s immune system

Chemicals In Foods

Sodium nitrate when ingested forms a potential carcinogen, nitrosamine
Sodium nitrate is still used because it is effective in preventing botulism
Pesticide and herbicide residues

Viral Factors

Herpes-related viruses may be involved in the development of leukemia, Hodgkin’s disease, cervical cancer, and Burkitt’s lymphoma
Epstein-Barr virus, associated with mononucleosis, may contribute to cancer
Human papillomavirus (HPV), virus that causes genital warts, has been linked to cervical cancer
Helicobacter pylori causes ulcers which are a major factor in the development of stomach cancer

Medical Factors

Some medical treatments actually increase a person’s risk for cancer
Diethylstilbestrol (DES) used 1940 to 1960 to control bleeding during pregnancy, the daughters of mothers that used DES were found to have an increased risk for cancers of the reproductive organs
Estrogen supplementation
Chemotherapy used to treat one form of cancer may increase risk for another type of cancer

Types Of Cancers

ØClassification of cancers
•Carcinomas
•Sarcomas
•Lymphomas
•Leukemias

Lung Cancer

In 2006, 174,470 people died from lung cancer
Since 1987, more women have died from lung cancer that breast cancer
Symptoms: persistent cough, blood-streaked sputum, chest pain
Treatment: surgery, radiation therapy, and chemotherapy
Prevention: avoid smoking and environmental tobacco smoke

Breast Cancer

1 out of 8 women will develop breast cancer (lifetime risk)
1 in 227: birth to age 39
1 in 25: ages 40-59
1 in 15: ages 60-79
Detection: mammograms, regular breast self-exams
Symptoms: lump in the breast, thickening, dimpling, skin irritation, distortion or tenderness
Risk factors: family history, hyperplasia, long menstrual history, obesity after menopause, oral contraceptives
Treatment: lumpectomy, radical mastectomy, radiation, chemotherapy
Prevention: exercise

Colon And Rectal Cancers

ØThird most common cancer in men and women with over 148,610 new cases diagnosed in 2006
Risk factors: over 50 years old, obese, family history of colon or rectum cancer or polyps, diets high in fats, low in fiber, smoking, high alcohol consumption, lack of exerciseMore Colors...
90% of colorectal cancers are preventable
Treatment: radiation, surgery, and possible chemotherapy
Prevention: regular exercise, a diet heavy in fruits and plant-origin foods, a health weight, and moderation in alcohol consumption

Prostate Cancer

ØMost common cancer in American men, excluding skin cancer
ØIn 2006, 234,460 new cases diagnosed
Ø1 in 3 men will be diagnosed in their lifetime
Prostate is a muscular, walnut-sized gland the surrounds part of the urethra.  Its primary function is to produce seminal fluid.
Symptoms: nonspecific, weak or interrupted urine flow, difficulty starting or stopping urination
Risk factors: age, race, nationality, family history, diet, lifestyle, and vasectomy
Prevention: diet high in lycopenes, vitamin E

Skin Cancer

Cancer-

Cancer starts out as a mutation in one gene in one cell.  Then the mutated cell starts dividing rapidly and taking over the whole area.

—LEUKEMIA is a cancer in blood-forming cells.
—LYMPHOMA is a tumor developing in lymphatic tissues.
—CARCINOMA is a tumor developing in any part of the epithelium.
—MELANOMA is a tumor developing in the pigment-producing cells of the skin. It is a particular type of carcinoma.
—SARCOMA is a tumor developing in muscles, bones, organs, and connective tissues.
 

CHARACTERISTICS OF CANCER CELLS

—1. LACK DIFFERENTIATION
—Normal cells have specialized functions, but cancer cells do not differentiate and do not contribute to the function of the body.
—2. ABNORMAL NUCLEI
—They have large or multiple nuclei with mutated chromosomes.
—3. FORM TUMORS
—Cancer cells grow and divide rapidly until they accumulate and form a lump of cancer cells called a tumor.  A BENIGN tumor is an accumulation of non-cancerous cells because they stay in their own capsule (encapsulated) and do not invade.

4. ANGIOGENESIS (INDUCE BLOOD VESSEL FORMATION)

—Since these tumors need nutrients, they create new blood vessels just for them to feed on.

5. METASTASIZE

—Pieces of the tumor break off and travel in the bloodstream to any new location, invade nearby tissues and continue their massive cell division and growth there. If there is a tumor in the lung, it is biopsied (the doctor surgically takes out a piece). If the cells are lung cells, it is lung cancer. But if the cells are pancreas cells, it is pancreatic cancer that has metastasized.
 

ORIGIN

—There are many factors that play a role in the development of cancer, including heredity factors, carcinogens, and mutagens.
—CARCINOGEN is an environmental agent that contributes to cancer. Not everyone exposed to it gets cancer. Examples of a carcinogen are ultaviolet radiation, toxic chemicals, and viruses.

MUTAGEN is an agent that increases chances of DNA change or mutation. Everyone exposed for long enough will get DNA mutations, and possibly cancer. Examples are x-rays and some medicines (thalidimide; caused birth defects

1. CARCINOGENS

—a) RADIATION is from overexposure to sunlight.
—b) ORGANIC CHEMICALS include tobacco, foods (salted pork), and pollutants

2. HEREDITY

DIAGNOSTIC PROCEDURES

—PAP SMEARS detect cervical cancers. They just swab the cervix and look at the cells under a microscope.
—MAMMOGRAMS are diagnostic procedures to detect breast cancer. The breast is just placed on a special type of machine like an x-ray.
—20% of breast cancers are not detected by mammogram and can only be detected by ultrasound.
—Those at high risk for breast cancer should get an MRI instead of a mammogram, since the x-ray might induce cancer.
—COLONOSCOPY is a diagnostic procedure to detect colon cancer. A scope is inserted into the rectum so the doctor can look for polyps.

Particular types of cancers run in families, such as breast, lung, and colon cancer

The American Cancer Society says the following are signs of cancer: C-A-U-T-I-O-N

—Change in bowel or bladder habits (colon cancer)
—A sore that does not heal (skin cancer)
—Unusual bleeding or discharge
—Thickening or lump in breast or elsewhere (breast cancer)
—Indigestion or difficulty swallowing (GI system cancer)
—Obvious change in wart or mole (skin cancer)
—Nagging cough or hoarseness (lung cancer)
 
PREVENTION OF CANCER-

1. BEHAVIORS

   

—DON’T smoke, sunbathe, drink alcohol, or get too many x-rays. Smoking cigarettes is associated with many types of cancers, including cancer of the lung, larynx, throat, and urinary bladder.

   

—DO be tested (self-breast exams and testicular self-exams every month, and Dr. check-ups), be aware of chemical hazards at work, and be aware that using estrogen for menopause symptoms must be combined with progesterone, otherwise there is an increased risk of cancer.

2. DIET

—Avoid fats, salty, smoke-cured, pork, and pickled foods.
—Eat plenty of fiber, green leafy vegetables and fruits, and eat cabbage, broccoli, Brussels sprouts, and cauliflower, vitamins A and C.
—
—For more information on smoke-cured meat, read the articles posted at the bottom of our Lecture Unit 1 webpage.

 

PREVENTION OF SKIN CANCER:

—A.   use broad-spectrum sunscreen
—B.   stay out of the sun altogether from 10-3
—C.   wear protective clothing
—D.   wear sunglasses
—E.   do not use tanning machines

 

TREATMENT OF CANCER-

1. RADIATION

—When someone has surgery to remove a tumor, it is often followed by radiation because the cancer cells may have spread throughout the body.  Cells that are in the process of dividing are the most likely cells to be killed by exposure to radiation. Since cancer cells are always in the process of dividing, exposing them to x-rays may kill them. The x-ray beam is coned down so just the tumor is exposed. However, scatter radiation kills off other cells that rapidly divide (stomach lining and hair follicles), so the side effects include baldness and nausea.

2. CHEMOTHERAPY

—This is for cancer that has metastasized. It is also good for cancer of the blood (leukemia). The drugs are designed to specifically kill just the cancer cells, but it tends to also kill off the normal blood cells that are just being formed in the bone marrow. Thus, bone marrow transplants are also needed sometimes.

3. BONE MARROW TRANSPLANTS

—Someone needs to volunteer to donate a small piece of bone from the crest of their hip. This bone marrow will contain healthy new blood cells that can repopulate the depleted bone marrow of the sick person. These cells are injected into the sick person’s vein.

4. IMMUNOTHERAPY

—Blood cells are taken from the sick person and are fused with an antibody that is specifically designed to seek out and destroy the cancer cell.

5. GENE THERAPY

—This is new research, attempting to find a gene that will shrink tumors.
 

6. COMPLEMENTARY THERAPIES

—This involves natural healing therapies such as biofeedback, acupuncture, and exotic foods. It’s worth a try if you’re going to die!
 

Long term effects of sun exposure can result in skin cancer
Malignant melanoma, deadliest form of skin cancer
Sun give off 3 types of harmful rays:
•UVA
•UVB
•UVC
Prevention: limit exposure to harmful UV rays, drink more fluids than usual, apply cool compresses to skin, moisturize skin

 

What to look for – The ABCD rule

•Asymmetry – half of mole does not look like the other half

•Border irregularity – the edges are uneven

•Color – pigmentation is not uniform

•Diameter – greater than 6mm

 

Ovarian Cancer

ØFifth leading cause of cancer death for women, 20,180 new cases diagnosed reported in 2006
ØMost common symptom is enlargement of the abdomen
ØRisk factors include: family history, age, childbearing, cancer history, fertility drugs, talc use in genital area, genetic predisposition
ØPrevention: diet high in vegetables and low in fat, exercise, sleep, stress management, and weight control

 

Cervical and Endometrial (Uterine) Cancer

 

9,710 new cases of cervical cancer, 41,200 cases of endometrial cancer in U.S. in 2006
Pap test – cells are taken from the cervical region
Risk factors:
•Cervical cancer: early age at first intercourse, multiple sex partners, cigarette smoking, and certain STIs
•Endometrial cancer: age, endometrial hyperplasia, overweight, diabetes, and high blood pressure

Other Cancers

ØPancreatic cancer – “silent” 4% 5-year survival rate
ØLeukemia – cancer of blood forming tissues

Detecting Cancer

ØThe earlier the diagnosis the better the prospect for survival
ØMagnetic resonance imaging (MRI)
ØComputerized axial tomography scan (CAT scan)
ØProstatic ultrasound
ØRegular self-exams, and check ups

New Hope In Cancer Treatments

Remove less surrounding tissue during surgery
Combine surgery with radiation or chemotherapy
Immunotherapy
Cancer-fighting vaccines
Gene therapy
Neoadjuvant chemotherapy
Stem cell research  

nucleus of every one of the human body's 30 trillion cells exists DNA, the substance that contains the information needed to make and control every cell within the body. Here is a close-up view of a tiny fragment of DNA. 

•Early diagnosis can often make a difference to how easily cancer is managed/treated and the chance of making of good recovery.weeks

Know Your Body and What is Normal for You

•If it turns out not to be serious, you’ve got peace of mind

•; if you smoke, stop doing so. If you fail to stop, do not smoke in the presence of non-smokers.

2)Avoid ObesityUndertake some brisk, physical activity Increase your daily intake and variety of vegetables and fruitsIf you drink alcohol, whether beer, wine or spirits, moderate your consumption Care must be taken to avoid excessive sun exposure. 

Food, nutrition and physical activity and the prevention of cancer

•Be physically active every day

•Eat mostly foods of plant origin

•Red meat

–Alcohol salt

•Add dietary supplements for cancer prevention

•Breastfeed children for at least six months

 

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