Unit 5: Cancer

Explain what cancer is

Cancer is the abnormal uncontrolled multiplication of cells due to genetic (DNA) mutations that disrupt the cell cycle. When cancer affects a major organ or system in the body to the point where organ function is significantly compromised then death occurs.

How does cancer spreads?

• Abnormal cells divide and create other abnormal cells

• Neoplasms (tumors) form

• Malignant tumor cells invade blood and lymphatic vessels and spread to distant sites and produce secondary tumour.

What is the difference between a benign and malignant tumor?

Benign tumours do not spread, however malignant tumours leave the primary location, spread to distant sites and produce secondary tumours.

What causes cells to mutate?

Exposure to carcinogens like asbestos, certain chemicals, acrylamide, UV light causes mutations that accumulate and lead to uncontrolled division that can form tumours.

How does cancer metastasis occur?

When cancer cells move into the circulation system and spread to other parts of the body colonizing other organs.

How can cancer damage the body?

• Tumours can block a blood vessel and interfere with body function.

• Immune system cancers can leave the body more vulnerable to negative effects of infection.

• Blood cancers do not produce tumours, however uncontrolled multiplication of cells still occurs

• Advanced tumors have a blood supply and can use up supplies of energy and nutrients.

Skin Cancer: risk factors, signs and symptoms, treatments and approaches to prevention

Highest incidence, lowest mortality.

• Most are carcinomas that grow slowly and are easy to treat.

• Malignant melanoma is the rarest but most deadly form of cancer.

• Risk factors; fair skin and hair, light eyes, tendency to burn, family history of melanoma.

• Use sunscreen

Breast Cancer: risk factors, signs and symptoms, treatments and approaches to prevention

Number 1 incidence in females.

• Risk factors: age, genetics, age at onset of menstruation, lifetime exposure to estrogen.

• High survival rate if caught early

• Prevention: mammograms and breast self-exams

• Treatment: surgical removal of tumour and adjacent lymph nodes, radiation, chemotherapy

Lung Cancer: risk factors, signs and symptoms, treatments and approaches to prevention

Leading mortal cancer in Canada

• Smoking is the #1 risk factor; followed by second hand smoke, asbestos, pollution

• No effective screening

• Symptoms don’t appear until late

• Treatment is difficult even in early stages

Prostate Cancer: risk factors, signs and symptoms, treatments and approaches to prevention

Most common cancer in men after non malignant skin cancer

• Risk Factor: age, obesity, physical inactivity, history of STIs, diets with excess animal fats, low plant matter.

• Can be detected by enlargement of prostate, changes in urine flow or frequency.

• Prevention: regular screening - digital rectal exam, prostate specific antigen test

• Treatment Options: surgery to remove prostate, radiation, cryotherapy, drugs

Function of prostate

Walnut sized gland near bladder that produces seminal fluid.

Colorectal Cancer: risk factors, signs and symptoms, treatments and approaches to prevention

Incidence has been increasing in young adults in their 20s and 30s. Begins as polyps in the intestine.

• Risk factors: age, male sex, inflammatory bowel disease, family history, smoking, obesity, alcohol abuse

• Symptoms: change in bowel movements, pain/tenderness in abdomen, blood in feces

• Prevention: colonoscopy, sigmoidoscopy, fecal blood screening

• Treatment: surgery, radiation and chemotherapy

Cervical cancer: risk factors, signs and symptoms, treatments and approaches to prevention

• Risk Factor: leading risk factor for cervical cancer is Human Papilloma Virus

• Prevention: HPV vaccine, screening, regular pap tests,

• Treatment: surgery, radiation therapy, chemotherapy

Discuss some of the causes of cancer and how risk can be avoided or minimized

• Carcinogenic chemicals - benzene, nickel

• Radiation - UV, x-ray

• Pathogens - HPV H. Pylori bacterium

Describe how cancer can be detected, diagnosed, and treated

• Screening which involves general examinations done on apparently healthy populations to identify those who may potentially have a disease.

• Testing is done on those who are believed to have a disease. It involves more specific tests to identify the presence of a cancer.

• Treatments include; surgical removal, chemotherapy, radiation, immunotherapy, gene therapy, hormone therapy.

Chemotherapy as cancer treatments (side effects)

• Use of drugs to target and kill cancer cells.

• This is an option when the cancer may have spread, although it affects not only cancer cells but normal body.

• Side Effects: loss, fatigue and nausea

Radiation Therapy as cancer treatments (side effects)

• Useful for localized tumor in combination with surgery or chemotherapy

• Beams focused from several directions resulting in higher dose at the tumour to kill cancer cells

• Side effects: DNA damage and kill healthy cells

Immunotherapy as cancer treatments (side effects)

• Stimulating the immune system with drugs

• Cancer vaccines for prevention: effective cancers caused by an infection (HPV)

• Cancer vaccines for treatment: effective against some cancers (Prostate) to boost immune system

Gene Therapyas cancer treatments (side effects)

• Modifying the genetic material of cancer cells

• Modifying genetic material of immune cells

• Use of altered

What is CRISPR?

• CRISPR is based on a natural defense system in bacteria against viruses.

• Bacteria store small pieces of viral DNA as CRISPR sequences.

• If the virus attacks again, these sequences are turned into RNA.

• The RNA guides an enzyme called Cas to find and cut the viral DNA.

• Scientists adapted this system into a gene-editing tool.

• CRISPR can be used to target and cut specific DNA sequences.

• It was first used in microbes and later in human cells for gene editing.

Hormone Therapy as cancer treatments (side effects)

• Effective against cancers that are helped by hormones (breast, prostate, ovarian cancer)

• Drugs that block hormone receptors or lower hormone levels

What is a biopsy?

Involves the removal of tissue that is suspected to be diseased for further examination

List specific actions you can take to lower your risk of cancer

• Don’t smoke, avoid second-hand smoke

• Reduce exposure to carcinogens

• Eat foods high in antioxidants, avoid burnt food, limit alcohol intake, keep a healthy weight

• Receive available vaccinations

• Get screenings for early detection