Cancer Flashcards
What are the hallmarks of cancerous cells
Self-sufficient in growth signals Insensitivity to anti-growth signals Tumour invasion and metastasis Lack of immune rejection Evading apoptosis Angiogenesis Limitless replication/uncontrolled proliferation
Describe a benign tumour
Can progress to cancer
Well encapsulated
Cells and Tissues appear normal
Do not spread to lymph nodes or distant location
Describe a malignant tumour
Rapid growth rates
Altered microscopic appearance
—->loss of cell differentiation
—->Absence of normal tissue organisation
Not encapsulated
Invades blood vessels, lymphatics and surrounding structures
Distant metastases
What are the 3 types of skin cancer
Basal Cell Carcinoma
Squamous Cell Carcinoma
Melanoma
What are the cells affected, characteristics and treatment options in Basal Cell Carcinoma
Arises from the stem cells in the basal layer of the epidermis or hair follicles
Slow growing and rarely spreads
Appears as a pearly lump or scaly, dry area that’s either shiny + pale or bright + pink
Treatment is guided by the stage and progression and includes Topical creams (Imiquimod), Surgical excision with 4mm - 5mm border, phototherapy, curettage + diathermy
What are the cells affected, characteristics and treatment options in Squamous Cell Carcinoma
Arises from Keratinocytes in the outer layers of the epidermis.
Rapidly growing lump that appears as a sore that’s not healed and may be painful to touch
Appears as a thickened red, scaly spot
Treatment is guided by the stage and progression and includes Surgical excision, Radiotherapy and/or Chemotherapy, curettage and diathermy.
What are the cells affected, characteristics and treatment options in Melanoma
Arises from the Melanocytes of the epidermis.
Differ in size, shape and colour and has irregular borders
Appears brown, black, blue or red.
May itch or bleed.
Treatment requires wide surgical excision due to the penetrating nature of the lesion.
The risk of sentinel node involvement increases with lesions >1mm thick.
—-> biopsy recommended
If +ve, lymphectomy, Chemotherapy and Radiotherapy are recommended
What is the relationship between sun exposure and skin cancer
The sun emits UVA and UVB rays which are absorbed by the skin and damage cell structures.
UVB is directly absorbed by DNA and causes change in a number of genes
UVA damages DNA by generating oxygen radicals that cause DNA molecules to break.
The changes seen in these genes, particulary ‘Tumour suppressor gene’ can decrease cell repair and induce uncontrolled cell proliferation.
Define Angiogenesis and relate to tumour formation
The formation of new blood vessels.
Due to rapid growth and proliferation, tumours secrete endothelial growth factor to stimulate angiogenesis.
This increase blood and nutrient supply to the tumour
Define Metastases and relate to tumour formation
The spread of cancer cells from the site of original tumour (primary tumour)
Cancer cells can spread through the vascular and lymphatic pathways, as well as through the tissues.
Common metastases sites include the liver, bone, lungs and brain. It is though that specific interactions between the cancer cells and tissue receptors influence where metastasis will occur
Why are some cancers more prevalent in older people
Some cancers take several years to develop and become symptomatic, so are not diagnosed til older age.
Also, at later stage in life the human cells have cumulative exposure to carcinogens, environmental and genetic influences that promote the development of cancer.
What are the common VIRAL causes of cancer
Common viral causes of cancer include Hepatitis B/C affecting the liver, Human Papilloma Virus affecting the cervix, and Epstein-Barr virus related to lymphoma and nasopharyngeal cancer.
What factors are relevant in the risk of developing cancer
lifestyle:
Cigarette smoking containing carcinogens
Western diet high in fat, sugar, salt red meat and low in fibre.
Abdominal Obesity, highly metabolically active and release free fatty acids within visceral organs
Environmental:
Pollutants and exposure to UVA/UVB rays
Electromagentic fields r/t mobile phone towers and mobile phone use
Occupational:
Carcinogen exposure such as asbestos, toxic chemical and smoke
Genetic:
Family history of cancers
Inherited altered genes such as the BRCA 1/2, p53
Mutations to oncogenes, tumour suppression genes and DNA repair genes.
How may diet and physical activity assist in preventing cancer
Physical activity reduces risk factors by increasing gut motility which decreases time the GI lining is exposed to potential carcinogens. Also reduces insulin and sex hormones (oestrogen and androgens) which in turn decreases exposure of these to breast tissue
High fibre diet promotes gut motility. Antioxidants can protect the DNA against damage. Various fruit and veg have protective substances against cancer
Discuss the clinical manifestations of pain, fatigue and cachexia in relation to cancer development
Early stages of cancer development may be asymptomatic. Pain may be attributed to compression, obstruction, inflammation, tearing or stretching of tissue or adjacent structures. Bone metastases cause referred pain in other bones and joints
Persistent tiredness is related to physiological impact of the cancer itself and/or cancer treatments. Fatigue is influenced by sleep disturbances, changes in chemical concentrations, psychosocial factors, physical activity levels, dietary/nutritional status. It is a subjective and highly individualised phenomenon.
Cachexia is severe tissue wasting and emacication. Fat stores and muscle loss occurs and the body appears excessively thin. Attributed to taste changes, early satiety, side effects of treatments and a hypermetabolic state.
Discuss the incidence of cancers across the lifespan
Cancer is more prevalent in the older adult
Leukaemia is the most common cancer in both male and female children
Testicular cancer and melanoma is seen in teenage males
Melanoma is seen in teenage females
Throughout early adulthood melanoma remains prevalent in both sexes
Breast cancer is seen in late adult females
Prostate cancer is seen in late adult to older adult males
Colorectal cancer is seen in older adult females
Describe the 3 key events involved in Carcinogenesis
INITIATION - the initial event when the cell is exposed to the carcinogen
PROMOTION - a secondary event when the cell is exposed to additional factors that promote growth of the transformed cells
PROGRESSION - the 3rd stage when the cellular changes become irreversible and express malignant characteristics
