Pathology of cancer Flashcards
Most prominent types of cancer
breast, prostate, lung, bowel, melanoma, barsa; cell carcinoma
avoidable risks of cancer
hormones (oestrogen- contraceptive pill), obesity, alcohol., breastfeeding= reduces risk of breast cancer by 5%, no clear risk factor for prostate cancer, lung cancer= smoking (79%) preventable
harder to manage risk factors
air pollution, workplace exposure to pollution, processed meat- bowel cancer, not enough fibre
terminology
cancer= highly invasive and destructive neoplasm, oncology- study of neoplasm, neoplasm- cells formed from irreversible deviant cell division, tumour- a collection of cells that have lost genetic control of proliferation and differentiation, malignant- invasive and destructive cells that don’t resemble cells of origin
benign tumours and malignant tumour suffix
benign- end in oma, malignant- carcinoma (epithelial or sarcoma (connective tissue)
benign tumour
differentiated cells, similar to normal cells, mitosis fairly normal, relatively slow growth, expanding mass- indicates problem, frequently encapsulated, remains localised, systemic effects- rare, only life threatening in certain location (e.g. brain)- in an area that we cant get to get rid off
malignant tumour
cells vary in size and shape with large nuclei, many undifferentiated cells, mitosis increased and atypical, rapid growth, cells not adhesive, infiltrate tissue, no capsule, invade nearby tissue or metastasis and lymph vessels, systemic effects- often present, life threatening by tissue destruction and spread of tumours
difference between normal cell proliferation and cancer cell
normal- cell proliferation= rate at which cells should be replaced, cell differentiation= have function
cancer cells- cells over proliferated, and undifferentiated cells
cancer occurs because of unrepaired gene malfunction
what causes cancer- altering genes
caused by altering genes that control the cells- reproduction- mitosis and meiosis, growth, differentiation, death. the cell is able to grow uncontrollably (altered proliferation) and loses its ability to carry out its specific function (altered differentiation) and does not die when expected
characteristics of cancer cells
angiogenesis causes increased blood supply to neoplastic cells, new antigen present on cell surface trigger immune response, lack of cell contact inhibition causes can increase in cell proliferation, changes in surface enzymes that degrade the extracellular matrix, lack of adhesions and cohesion makes cells slipperty and able to move easily= increased movement to other locations in cell body, secretions of substances alters metabolic processes of unaffected cells and increases growth of neoplastic cells, enlarged nucleus provides increased energy to rapidly dividing cells
impact of cancer on tissue, organs and organ system
loss of cell to cell communication which allows further unrestricted growth of tumour cells, increased energy expenditure- deprives unaffected cell of nutrient, increase motility and loss of cohesion and adhesions- promotes movement to other locations, rapid angiogenesis which provides extensive blood flow to tumour, substance secretion- which alters the metabolism and deflates neighbouring cells, present foreign antigens on the cancer cell surface which can trigger immune response
major categories of cancer cells
mutator gene- gene that repair mutated DNA and protect genome, protooncogenes- genes that regulate cell function, tumour suppressor genes- genes that prohibit proliferation of cells and regulate apoptosis, P53 gene, Rb gene- retinoblastoma, osteosarcoma, breast cancer, pancreatic cancer and lung cancer
BCL-2= gene- leukaemia
mechanisms of cancer
cell exposed to carcinogenic agent= DNA damage (failure of DNA repair)= mutation in cell genes= activation of growth promotion oncogenes or activation of apoptosis controlling genes or activation of tumor suppressing antioncogenes= unregistered cell growth and differentiation= cancer
3 phases of cancer
initiation phase- carcinogenic agent, DNA damage and cell mutation,
promotion phase- activation of oncogenes by promoting agent,
progression (malignant tumour)
once in progressive phase it doesn’t matter if you get rid of promotion phasem it will still be progressive
carcinogens- high energy ionising radiation
Y rays, X rays, UV rays
causes genetic damage in cell, can kill cells directly
carcinogens- hormones
some tumour cells are responsive to hormones for growth, Ca of breast cancer, uterus, prostate and adrenal glands
carcinogens- chemicals
tobacco- lung, laryngeal, lip, oesophageal, bladder Ca, asbestos, benzene, insecticides, formaldehyde
carcinogens- viruses and bacteria
HPV, hepatitis B or C, retroviruses (e.g. HIV), helicobacter pylori
spread of cancer- local spread and direct extension
local- proliferation of the neoplasm within the tissue of origin
direct- process of tumour moving into adjacent tissues and organs
spread of cancer- seeding and metastases
seeding- malignant tumour move along membranes of peritoneal and pleural cavities, gaining easy access to organs within
metastases- neoplasm spread to distinct sites by way of lymphatic or blood vessels
tumour staging
size, extent, spread, nodes
cancer classification- grades 1 and 2
tumour grading- level of anaplasia
grades 1 and 2- well differentiated, resembles the tissue of origin in size and shape, structure and mitotic activity
cancer classification- grades 3 and 4
highly undifferentiated, demonstrate little resemblance, tissue or origin
warning signs of cancer
unusual bleeding or discharge anywhere in the body, change in bowel or bladder habits, a change in wart or mole, a sore that does not heal, unexplained weight loss, anaemia or low Hb or persistent fatigue, persistent cough without reason, a solid lump often painless, in breast or testes of anywhere on the body
general manifestations of cancer
systemic inflammatory and immune response- fever, anorexia, weight loss,
increased metabolic rate, paraneoplastic symptoms- indirect changes in body function, local effects of tumour on neighbouring tissues- occupies space- palpable mass and pain, loss of function- constipation, diarrhoea and SOB, changes in blood
diagnostic tests
complete history, physical examination, imaging studies- X rays/ MRI, biopsy and cytology studies, tumour markers- hormones, enzymes immunoglobulins, protein antigens (PSA= prostate, hGG= testes), CA125 (ovarian, uterine, cervical, pancreatic, lung, colon, breast), CEA (colorectal but many others), blood urine and tissues rests
cancer treatments
3 possible goals- completely eradicate the neoplasm, control continued growth and spread, reduce symptoms without curing cancer
treatment
chemotherapy, radiotherapy, surgery, hormones, immunotherapy, bone marrow/ stem cell transplantation, adjuvant therapy- additional prophylactic treatment used in cancers known to metastasis breast cancer
each strategy is dependent on cancer and may use alone or in combination
prognosis- many factors affect course and outcome
type- pancreatic/ lung cancer have poor outcome (late diagnosed), location, stage of disease, age, overall health, response to treatment,
prognosis- 5 year survival rate
percentage of persons who are living 5 years after diagnosis, cancer free, in remission, living with cancer
cancer prevention
screening- breast/ bowel/ cervical, exercise, balanced healthy diet, maintain healthy weight, vaccinations, skin protection, avoid tobacco, avoid alcohol consumption, protect against exposure to industrial carcinogens
