chap 8: cancer Flashcards
what is cancer?
the abnormal, uncontrolled multiplication of cells that ultimately cause death if left untreated
tumor
a mass of tissue that serves no physiological purpose
benign tumor
-noncancerous
-made up of cells similar to surrounding cells and enclosed in a membrane preventing them from penetrating neighbouring tissues
-dangerous when it interferes with bodily functions
malignant tumour
-synonymous with cancer
invades surrounding structures (blood vessels, lymphatic system and nerves
-spreads via blood and lymphatic circulation and forms tumours in almost any part of the body
-not all cancers produce a mass (leukemia) but are still malignant
how does cancer begin
a malignant cell divides without regard for normal control mechanisms and gradually produces a mass of abnormal cells/ tumour
-takes a billion cells to make a mass the size of a pea
–> a single tumour cell goes through many divisions, taking years before it grows to a noticeable size
-produces a sign or symptom (lump, persistent cough, unexplained bleeding/pain)
metastasis
-spreading of cancer cells from one part of the body to another –> occurs bc cancer cells do not stick to each other and do not remain at the original location (primary tumour)
-break away through lymph or blood vessels to invade nearby tissue
-tumour can recruit normal cells, modify them and use them to travel to different parts of the body and prepare other sites from travelling cancer cells
–> create proteins that attract free-floating cancer cells that gather at new sites and replicated
–> new tumours called secondary tumours metastases
staging
classifying the progress/ extent of cancer in a person
stages of cancer
0: precancerous change
1: tumour is typically small and not grown outside the organ it started in
2+3: tumour is larger or has grown outside the organ it started in to nearby tissue
4: the cancer has spread through the blood or lymphatic system to a distant site in the body (metastatic spread)
remission
signs and symptoms of cancer disappear + disease is considered to be under control
- results from treatment
types of cancer
carcinoma: covers external body surfaces, line internal tubes and cavities, form secreting portion of glands. ex. skin, breast, uterus, prostate, lungs, and GI tract
sarcoma: arise from connective and fibrous tissues –> muscle, bone, cartilage, and the membrane covering muscles and fat
lymphomas: cancers of lymph nodes, part of the bodys infection-fighting system
leukemia: blood forming cancer cells, reside in bone marrow
lung cancer
- most common cause of cancer death
-risk factor: tobacco smoke, environmental tobacco smoke, low income
-symptoms: persistent cough, chest pain, recurring bronchitis
-CT scans can detect lung cancer early even though its difficult to detect in its early stages ( symptoms)
treatment: can be treated with surgery, radiation. chemotherapy, phototherapy, gene therapy, immunotherapy
colon/rectal cancer
-3rd most common type of cancer
-risk factor: age (50 or older), heredity, chronic bowl inflammation, type 2 diabetes. lifestyle, excessive alcohol use and smoking, obesity, lower income
-symptoms: bleeding from rectum, change in bowel habits
treatment: regular fecal tests 12-30 months for Canadians 50 or older to test amount of blood in stool, sigmoidoscopy, surgery is primary treatment. radiation and chemo before surgery to shrink a tumour
breast cancer
- most common cancer in women (1/8 will have it and 1/34 will die)
-risk factors: strong genetic component, early onset menstruation, late onset of menopause, having no children or having first child after 30, high breast density, current use of hormone replacement therapy, obesity, physically inactive, alc use
-early detection: mammogram, ultrasound, breast self exams
treatment: lump will be scanned to determine if cancerous (ultrasonography + biopsied) –> lumpectomy, mastectomy), lymph nodes from armpit are removed and examined to see if the cancer spread. hormone therapy, antibody therapy, radiation, chemotherapy, SERMS
survival rate: if tumour is discovered before spread = 100% chance of survival more than 5 years, 88% for all stages at 5 yrs and 84% at 10 yrs, 87% across all ages
prostate cancer
- most common cancer in men
-3rd leading cause of death in men
-risk factors: AGE (age 50 and over 65), inherited genetic predisposition (5-20%), Black, unhealthy diets, history of STDs, type 2 diabetes
-detection: early–> no symptoms, changes in urinary frequency, painful + blood in urine. can be detected prostate-specific antigen (PSA) blood test, ultrasound, a needle biopsy
-treatment: radical prostatectomy, surgical implantation of radioactive seeds, external radiation, cryotherapy, chemotherapy
-5 yr survival rate 94 percent
cervical cancer
-women in 20’s-30’s
-sexually transmitted infection (HPV)
-a very percentage of hpv infected women get cervical cancer
-risk factors: smoking and infection w/ genital herpes, HPV 16
detection: pap test
diagnosing cancer
-biopsy: confirms the type of tumour
-mri: detects hidden tumours by mapping
-ct: xray for cross-section of tumour’s shape and location, precise location for accurate radiation dosage
-ultrasonography: used in physicians office, less expensive, and completely safe
treating cancer
-goal is to kill/remove all cancerous cells while leaving normal tissue untouched
-ex is surgically removing a tumour
-if its less accessible then a combo of surgery, radiation therapy, and chemotherapy is needed
chemotherapy
-destroys quickly growing cancer cells
-causes dmg to normal tissues such as intestinal, hair and blood forming cells (side effects such as nausea, vomiting, diarrhea and hair loss
-can be given before or after surgery (before is induction chemotherapy) and that depends on the cancer
palliative chemotherapy is when the cancer cannot be cured from chemo but still benefit from it
radiation
-beam of xrays or gamma rays is directed at the tumour
-small organs can have radioactive seeds surgically placed and removed later if necessary
-destroys both normal and cancerous cells
immunotherapies
boosts immune systems response to cancer
-ex. monoclonal antibodies selectively kill cancer cells and only bind to that cell surface marker
CAR-T cell therapy
-chimeric antigen receptors that are injected to the patient and recognize antigens on the tumour cells and bring immune t cells near the cancer cells
hormone therapies
-blocks the bodys ability to produce hormones or interfere with how they act + tumour cells can be tested for the presences of hormone receptors
-prostate and breast cancers
dna mutations and cancer
-can be inherited
-environmental: radiation, certain viruses, and chemical substances
oncogenes
genes involved in transformation of normal cell into cancer cell
-control or restrict cell growth (tumour suppressor genes)
–> if mutated, releases the brake on growth and leads to rapid and uncontrolled cell division
-ex. p53, BRCA1 (breast cancer gene 1) BRCA2
cancer promoters
-carcinogenic agents (uv radiation) known as cancer initiators
-accelerate growth of cells w/o dmging or permanently altering dna
-estrogen: stimulates growth in female reproductive organs is a cancer promoter
-cigarette smoke is a complete carcinogen its both initiator and promoter
tobacco use
-85% of lung cancers and abt 30% of all cancer deaths
-48000 deaths annually
dietary factors
- maintaining a healthy weight and a diet rich in fruits and vegetables lowers the risk of cancer
-omega 6 polysaturated fats are associated w/ higher risk of certain cancers than diets favouring omega 3 fats (fish and canola oil)
-high intake of sugar is high risk of obesity and obesity is a risk for variety of cancers (endometrial, colorectal and pancreatic)
-alc (15% risk of breast cancer , oral, colon cancer)
-high temp cooking: acrylamide in starch based foods that are fried or baked at high temps
-fibre: high fibre diet is recommended
-anti carcinogens (vit C, E, selenium and carotenoids) as well as calcium and folic acid, phytochemicals
carcinogens in environment
-microbes (viruses, bacteria, and parasites) –> epstein barr, hepatitis b and c
-ingested chemicals (nitrates and nitrites in processed meat
-environmental and industrial pollution (fossil fuels and their combustion products)
–> radon, asbestos
-radiation
stem cell transplants
-restores blood forming cells in ppl who had their own cells destroyed by high-dosage radiation therapy or chemotherapy
-stem cells are taken from a donor and then transplanted into the bloodstream, then bone marrow and then take place of the cells that were destroyed
experimental tech
-liquid biopsy: less invasive and repeated multiple times. drawing a sample of urine/blood
starve or feed tumours?
-starving: tumours grow back more aggressively by forming new blood vessels and lay down highways of collagen and the cells can develop stem cells to repopulate. also become more resistent to chemo
feeding o2: can be more efficiently killed by chemo as tumours wont enter panic mode and form super tumours
preventing cancer
-live smoke free
-maintain a healthy diet and weight
-sit less and move more
-protect your sin
-avoid environmental and occupational carcinogens
