Cancer Notes

Understanding Cancer

• Definition: Cancer is a group of cells that have lost their normal control mechanisms, leading to unregulated growth.

• Develops from any tissue within any organ.

• Characterized by uncontrolled cell division, resulting in malignant growth or tumors.

Tumors

• As cancerous cells grow and multiply, they form a mass of cancerous tissue called a tumor.

• Tumors can be:

  • Benign (non-cancerous): grow locally and do not spread by invasion or metastasis.

  • Malignant (cancerous): invade neighboring tissues, enter blood vessels, and metastasize to different sites.

Development and Spread of Cancer

• Cancerous cells develop from healthy cells through a complex process called transformation.

• Initiation:

  • The first step involves a change in the cell's genetic material, causing it to become cancerous.

  • This change can occur spontaneously or be caused by a carcinogen (an agent that causes cancer).

• Promotion:

  • The second and final step in cancer development.

  • Promoters are agents that allow a cell that has undergone initiation to become cancerous but do not cause cancer on their own.

• Cancer starts when normal cells transform into abnormal cells, which then multiply, leading to cancer in situ. This progresses to malignant or invasive cancer through angiogenesis, where tumors grow their own blood vessels.

• Cancer spreads through local invasion and metastasis. Metastasis occurs when cells invade other parts of the body via blood and lymph vessels.

Types of Cancer

Leukemias:

• Cancers of the blood and blood-forming tissues.

• Do not form lumps.

• Harm the body by crowding out normal blood cells in the bone marrow and bloodstream.

• Common Symptoms:

  • Systemic: Weight loss, fever, fatigue, loss of appetite.

  • Lungs: Easy shortness of breath.

  • Muscular: Weakness.

  • Bones or Joints: Pain or tenderness.

  • Psychological: Fatigue

  • Lymph Nodes: Swelling

  • Spleen and/or Liver: Enlargement

  • Skin: Night sweats, easy bleeding and bruising, purplish patches or spots.

Lymphomas:

• Signs and Symptoms:

  • Lymph nodes enlargement

  • Lungs cough

  • Liver enlargement

  • Kidney nephrotic syndrome

  • Weight loss

  • Night sweats

  • Skin itch

  • Spleen enlargement

  • Neck lump caused by swollen lymph nodes

  • Bone marrow involvement

Carcinomas:

• Cancer of epithelial cells.

• Include cancers of the:

  • Skin

  • Breast

  • Lung

  • Prostate

  • Colon

  • Thyroid gland

  • Stomach

• Occur more often in older people than in younger ones.

• Basal Cell Carcinomas:

  • Rarely spreads

  • Found deep within skin layers of thick skin

  • Occupies basement membrane

  • Most common form of NMSC

  • 96% of victims 40 years or over

  • Red, pale or pearly in colour

• Squamous Cell Carcinomas:

  • Spreads more commonly than BCC's

  • Found near body orifices and in the oral cavity

  • Occupies outer layer of skin

  • Less common but more dangerous

  • Almost all victims of SCC 40 years or older

  • Thickened, red, spot, may bleed, crust or ulcerate

Sarcomas:

• Cancers of the mesodermal cells.

• Include:

  • Leiomyosarcoma: cancer of smooth muscle

  • Osteosarcoma: bone cancer

• Typically occur more often in younger people than in older ones.

• Examples on the slide: includes cancers of Blood vessels, Lymph vessels, Skin and fat, Bone and cartilage

Common Cancers:

• Lung

• Breast (women)

• Leukemias (Bloodstream)

• Lymphomas (Lymph nodes)

• Colon

• Bladder

• Prostate (men)

• Fat

• Bone

• Muscle

• Throat Cancer

• Cancer of the Oesophagus

• Stomach Cancer

• Bowel Cancer

• Cancer of the Bladder

• Cancer of the Uterus or Cervix

• Skin Cancer

• Ovarian Cancer

• Testicular Cancer

Most Common Cancers Worldwide:

• Women:

  • Breast

  • Lung

  • Stomach

  • Cervical

  • Colorectal

• Men:

  • Lung

  • Stomach

  • Liver

  • Prostate

  • Colorectal

• Cancers Causing Most Deaths (2007):

  • Lung: 1.4m

  • Stomach: 866,000

  • Colon: 677,000

  • Liver: 653,000

  • Breast: 548,000

Naming Cancers:

• Cancer Prefixes Point to Location

  • adeno- gland-

  • chondro- cartilage

  • erythro- red blood cell

  • hemangio- blood vessels

  • hepato- liver

  • lipo- fat

  • lympho- lymphocyte

  • melano- pigment cell

  • myelo- bone marrow

  • myo- muscle

  • osteo- bone

Immunogenicity, Risk Factors, and Symptoms of Cancer

Signs & Symptoms:

• Unusual Fatigue

• Backaches

• Abdominal Swelling and/or Pain

• Bloating and/or a Feeling of Fullness

• Persistent, Gastrointestinal Complaints such as Gas, Nausea and Indigestion

• Frequency and/or Urgency of Urination

• Abnormal or Postmenopausal Bleeding

• Change in Bowel Habits

• Unexplained Weight Loss or Gain

Bodily Defenses Against Cancer

• The immune system can recognize and destroy cancer cells.

• Cancer progression is more likely in individuals with altered or impaired immune systems.

• The immune system uses various cells (e.g., natural killer cells, macrophages, cytotoxic T cells) and antibodies to combat cancer.

• Tumor antigens can help contain or destroy cancerous cells, but even a fully functioning immune system cannot always destroy all cancerous cells.

• Tumor antigens can be detected with blood tests, known as tumor markers. These markers are used for screening, diagnosis, and evaluating treatment response. The slide enlists tumor markers for different parts of the body.

Risk Factors

• Family History & Genetic Factors

• Age

• Environmental Factors

• Geography

• Proportion of Cancers Caused by Major Risk Factors in developed and developing countries.

  • Developed Countries:

    • Tobacco: 30%

    • Diet or Nutrition: 39%

    • Infections: 5%

    • Other: 26%

  • Developing Countries:

    • Tobacco: 16%

    • Diet or Nutrition: 10%

    • Infections: 8%

    • Other: 44%

    • Environmental pollution: 2%

    • Occupational exposures 5%

• Diet

• Viral Infections

• Inflammatory Diseases

• Lower risk:

  • Maintaining a healthy weight.

  • Being physically active.

  • Eating a diet high in plant foods, including vegetables, fruits, whole grains and beans.

  • Eating a diet low in red meat and avoiding processed meat.

  • Limiting alcohol, if you drink at all

  • Avoiding sugary beverages

  • Eating a diet low in salt

  • Breastfeeding and having been breastfed

  • Not smoking

• Higher risk:

  • Being overweight or obese

  • Eating a diet high in red and processed meat

  • Eating a diet low in whole grains and beans

  • Eating a diet low in vegetables and fruits

  • Not being physically active

  • Drinking alcohol

  • Drinking sugary beverages

  • Eating a diet high in salt, fat and sugar

  • Not having been breastfed

  • Smoking

Lung Cancer Risk Factors

• Smoking, secondhand smoke, radon, asbestos (particularly among smokers), certain metals (chromium, cadmium, arsenic), some organic chemicals, radiation, air pollution, and a history of tuberculosis.

• More than 150,000 Americans die every year from lung cancer - it's the most common cause of cancer death in the U.S.

• The risk of getting lung cancer grows significantly with multiple causes with examples:

  • No Risk Factors: Normal Risk of Cancer

  • Asbestos Exposure: 6x The Risk

  • Smoker: 11x The Risk

  • Smoker+Asbestos: 59x The Risk

  • Non-smokers living with a smoker have a 24% risk of developing lung cancer.

Symptoms

• Some develop early; others develop only after cancer progresses

• Seven Warning Signals of Cancer:

  1. A change in bowel or bladder habits

  2. A sore that does not heal

  3. Unusual bleeding or discharge

  4. Thickening or a lump in the breast or elsewhere

  5. Indigestion or difficulty in swallowing

  6. Obvious change in a wart or mole

  7. Nagging cough or hoarseness

• At first, cancer produces no symptoms

• Cancer growing in an area with a lot of space may not cause any symptoms until it becomes larger. In contrast, A cancer growing in a restricted space may cause symptoms when it is relatively small

• Early detection of cancer can save lives. Know the warning signals listed in the slide.

• Cancers produce symptoms by:

  • Growing into & irritating or destroying other tissues

  • Putting pressure on other tissues

  • Producing toxic substances

  • Using energy & nutrients normally available for other bodily functions

• A number of complications can result, some serious and requiring emergency treatment.

• SAINT SILUAN Warning signs for cancer in children:

  • S = Spots: White spot in the eye, new squint, blindness, bulging eyeball

  • L = Lump: Abdomen and pelvis, head and neck, limbs, testes, glands

  • U = Unexplained: Fever, loss of weight and appetite, pallor, fatigue, easy bruising or bleeding

  • A = Aching: Bones, joints, back, and easy fractures

  • N = Neurological Change in behaviour, balance, gait, and milestones, headache, enlarging head

• Pain:

  • Painless at first.

  • As the cancer grows, the first symptom is often a mild discomfort.

  • The pain may result from the cancer compressing or eroding into nerves or structures.

• Bleeding:

  • At first, a cancer may bleed slightly because its cells are not well attached to each other, & its blood vessels are fragile

  • Later, as the cancer gets bigger & invades surrounding tissues, it may grow into a nearby blood vessel, thus causing bleeding

  • The site of the cancer determines the site of the bleeding. For example, cancer in the digestive tract will cause bleeding in the stool

• Weight Loss & Fatigue:

  • Increases as cancer progresses.

  • People may become very thin.

  • People with advanced stage cancer are often very tired & sleep many hours a day

• Swollen Lymph Nodes:

  • May be painless or tender

  • May be freely movable, or if the cancer is more advanced, may be stuck to the skin, the deeper layers of tissue, or both

• Depression:

  • Can be related to the symptoms of the illness, a fear of dying, & a loss of independence.

  • Some cancers may produce substances that directly cause depression by affecting the brain

• Neurological & Muscular Symptoms:

  • Cancer can grow into or compress nerves causing a change in sensation, weakness or muscle.

  • When cancer grows in the brain, it may cause:

    • confusion

    • dizziness

    • headaches

    • nausea

    • changes in vision

    • seizures

• Respiratory Symptoms:

  • Cancer can compress or block the lungs causing:

    • shortness of breath

    • pneumonia

    • inability to cough up secretions

Warning Signs, Complications, Diagnosis, and Prevention of Cancer

Warning Signs of Cancer:

• Weight loss

• Fatigue

• Night sweats

• Loss of appetite

• New, persistent pain

• Recurrent nausea or vomiting

• Blood in urine

• Blood in stool

• Sudden depression

• A recent change in bowel habits (constipation or diarrhea)

• Recurrent fever

• Chronic cough

• Changes in size or color of a mole

• Changes in a skin ulcer that doesn't heal

• Enlarged lymph nodes

Cancer's Seven Warning Signs:

• The American Cancer Society has developed a simple way to remember the seven warning signs of cancer. Each letter in the word CAUTION represents a possible warning sign that should prompt an individual to see his health care provider.

• Change in bowel or bladder habits

• A sore that doesn't heal

• Unusual bleeding or discharge

• Thickening or lump in the breast or elsewhere

• Indigestion or difficulty swallowing

• Obvious change in a wart or mole

• Nagging cough or hoarseness

• Potential Warning Signs of Cancer that People Too Often Ignore include:

  • Unexplained weight loss

  • Shortness of breath

  • Weakness and fatigue

  • Frequent fevers or infections

  • Chronic cough and chest pain

  • Bloating

  • Chronic heartburn

  • Bowel problems

  • Difficulty swallowing

  • Pelvic or abdominal pain

  • Jaundice

  • Changes in nails

Some Complications of Cancer

Cardiac Tamponade:

• Occurs when fluid accumulates in the baglike structures surrounding the heart.

• Fluid can accumulate when cancer invades the pericardium & irritates it.

• Types of cancers involved: lung & breast cancer, lymphoma.

• Compression of the heart due to fluid accumulation within the pericardium

Pleural Effusion:

• Occurs when fluid accumulates in the baglike structure around the lung.

• Causes shortness of breath.

Superior Vena Cava Syndrome:

• Occurs when cancer partially or completely blocks the vein that drains blood from the upper part of the body into the heart.

• Blockage causes the veins in the upper part of the chest & neck to swell.

• Manifestations of supra-azygos SVC obstruction:

  • Distended arm and neck veins

  • Edema of neck, face and arms

  • Congested mucous membranes (mouth)

  • Dilated, tortuous vessels on upper chest

• Manifestations of infra-azygos SVC obstruction:

  • More severe symptoms but all of the features for obstruction distal to entrance of SVC

  • Dilation of collateral vessels on anterior and posterior abdominal wall with downward and back blood flow into IVC, then back to heart

Spinal Cord Compression:

• Occurs when cancer compresses the spinal cord or the spinal cord nerves.

• Causes pain & loss of function.

• Uterus

• Bladder

• Sexual organs

• Legs

• Bowel and anus

• Long-term :

  • Permanent death of spinal nerve

  • Dysfunction below the level of the canus jury

Brain Dysfunction:

• Occurs when the brain functions abnormally as a result of a cancer growing within the brain.

Diagnosis

• Screening programs allow early detection & diagnosis of cancer.

• The earlier cancer is diagnosed, the more effective treatment is likely to be.

• Includes screening, testing, & a physical examination.

• After a cancer is diagnosed, it is staged.

• Staging: a way of noting how advanced the cancer has become.
  *Includes:

• Stage 0- carcinoma is in situ

• Stage I- Cancer is small

• Stage IIA, IIB

• Stage IIIA

• Stage IIIB

• Stage IV- cancer has spread to other areas of the body

The ABCDE System of Melanoma Detection:

• The ABCDE criteria represent a commonly used clinical guide for early diagnosis of melanoma. The following features are considered suspicious:

  • Asymmetry: Moles that have asymmetrical appearance

  • Border: A mole that has blurry and/or jagged edges

  • Color: A mole that has more than one color

  • Diameter: Moles with a diameter larger than a pencil eraser (6 mm or 1/4 inch)

  • Evolution: A mole that has gone through sudden changes in size, shape or color

Preventing Cancer

• The risk of developing certain cancers may be reduced by making lifestyle changes according to what the American Cancer Society recommends

• Measures known to reduce the risk of cancer:

  • Avoid smoking or exposure to tobacco smoke

  • Avoid occupational carcinogens

  • Avoid prolonged exposure to sunlight without sunscreen protection

• Measures that possibly reduce the risk of cancer:

  • Limit the intake of high-fat foods

  • Increase the intake of fruits & vegetables

  • Be physically active

  • Achieve & maintain a healthy weight

• According to the slide key causes of cancer are:

  • Tobacco

  • Alcohol

  • Lack of fruit & vegetables

  • Meat

  • Lack of fibre

  • Overweight

  • Lack of physical exercise

  • Post-menopause

  • Infections

  • Ionising Radiation

  • Occupational hazard

  • Sun exposure & sunbeds

Cancer Treatment

Surgery:

• One of the oldest forms of cancer treatment

• Most effective treatment

• Primary means of treating tumors

• Can't be used for all early-stage cancers

Radiation Therapy:

• Radiation: beam or field of intense energy focused on a certain area or organ of the body

• Kills cells that divide rapidly

• Can damage normal tissues adjacent to the tumor

• Therapy is divided into a series of doses over a long period of time

• Therapy plays a key role in curing many cancers

• Steps include imaging, targeting radiation beams, delivering high-energy radiation, and damaging cancer cells.

Chemotherapy:

• Involves the use of drugs to destroy cancer cells

• Drugs are designed to inflict greater damage on cancer cells than on normal cells

• Drugs affect normal cells & cause side effects *Chemotherapy:

  • prevents blood vessel growth

  • stops cell division/ replication process

  • creates a non-dividing cell by altering cell structure

  • causes spontaneous cell death

• Chemotherapy, alone or combined with radiation, may be used before, after or instead of surgery in treating lung cancer.

Immunotherapy:

• Purpose is to stimulate the body's immune system against cancer

• Some Use vaccines composed of antigens derived from tumor cells to boost the body's production of antibodies or immune cells

• complex binds to dendritic cell precursor

• tumor antigen is linked to a cytokine

• Patients blood is drawn

• The complex is taken in by dendritic cell precursor

• Dendritic cell matures and is infused back into patient

• Dendritic cell displays tumor antigen and activates T cells

• T cells attack cancer cell

Combination Therapy:

• Commonly, several chemotherapy drugs are combined

• These drugs work on different parts of the cancer cell's life cycle

Alternative Medicine:

• Include medicinal herbs

• May be used to treat cancer, but not many have been subjected to careful scientific studies

Global Impact of Cancer

• Cancer is a global killer, accounting for 7.4 million deaths worldwide and being the leading cause of death globally (13% of all deaths).

• The most frequent cancer types and their mortality include Lung, Stomach, and Colorectal.

• There are more than 100 cancer types. Any part of the body can be affected

• In the developed world

  • 1 in 3 people will develop cancer during their lifetimes

• Across the world:

  • 1 in 9 people have a risk of developing cancer again if they survived the first

  • 2 in 9 people have an increased risk of developing a second primary cancer

• 70% of all cancer deaths occur in low and middle income countries

• More than 30% of cancer could be prevented, mainly by not smoking tobacco, having a healthy diet, being physically active and preventing infections that may cause cancer

• A third of cancers could be cured if detected early and treated adequately.

• Slide enlists leading cancer killers.

Pediatric Cancer

• Every day 46 kids are diagnosed with cancer

• Every day 7 children will die from cancer

• Pediatric Cancer kills more kids than Cystic fibrosis, pediatric AIDS, and asthma COMBINED

• 1 in 330 children will develop cancer by age 20

• Treatment side effects can last a lifetime for these kids

• Spread the knowledge

• September is childhood cancer awareness month

• Childhood Cancer - Current Long-Term Outcomes

  • 22% Live at least 30 years and don't suffer chronic health conditions

  • 34% Die within 30 years

    • 20% die in years 1 to 5

    • 14% die in years 6 to 30

  • 25% Survive at least 30 years but suffer mild or moderate chronic health conditions

  • 19% Survive at least 30 years but suffer life-threatening or disabling chronic health conditions