Cancer Flashcards
Proliferation
Rate of proliferation = Rate of degeneration
Stop and go signals
Contact inhibition
normal cells respect boundaries of other cells and don’t grow into the territories
Telomerase
DNA telomere protein cap naturally gets smaller as cells divide, and stop once it reaches certain length
In cancer, telomerase enzyme adds them back so it keeps dividingC
Cell growth regulators
Proto-oncogens = promote growth (become oncogens in cancer and hyperactive proliferate)
Tumor suppressor genes = suppress growth (in cancer theye dont work anymore)
Carcinogenesis
Development of cancer
1) Initiation stage (mutation occurs)
- Mutation in cell from carcinogens, inherited, or error
Carcinogenes = chemical, radioactive or virus
When occurs, cell either dies, repairs or replicates and becomes cancerous
2) Promotion stage
Reversible where proliferation of altered cells, more likely to become cancer in prescence of promoting factors
E.g. obesity, dietary fat, cigarette smoking and alcohol
3) Progression stage
Increased growth of tumor, metastasis
Benign and malignant
Benign - grow slowly, well differentiated, does not spread (eg. moles, uterine fibrioids)
Malignant - grows rapidly, poorly differentiated, metastases occurC
Classification of cancer
i) Anatomical site = origin of tumor, solid or haematological
ii) Histological analysis (grading) = more differentiated, the more benign so how close they resemble the cells they come from
iii) Extent of disease (staging) = help guide treatment, location of cancer and metstasis (Stage 1 and 2 is more localized, 3 and 4 is difficult to control)
TNM classification
T = Tumor size
N = spread to lymph nodes
M = Metastasis
Side effects
i) Local
Benign can also cause local problems
Occlusion eg. colon cancer
Ulceration eg. invade other tissues
Pain esp in bone metastases and nerve pressing
Infarction - cancer cells become its own supply and rob blood from surrounding cells
ii) Systemic
Weight loss = cachexia as it rob nutrients
Bleeding from eroding blood vessels and necrosis
Anemia from less RBC production
Clinical manifestations
Pain - can be direct pressure, obstruction, destruction, infection, inflammation
Brain tumor = HA
Fatigue - weakness, lack of energy, constant hypermetabolic state
Cachexia - wasting syndrome, possibly because the body is fighting cancer and proinflammatory cytokines released (breaks down protein and fats)
Anemia, thrombocytopenia and leukopenia
Anemia = chronic bleeding, malnutrition, common in GI cancers
Leukopenia - tumor invasion of one marrow, high risk of infection
Paraneoplastic syndrome
Rare syndrome where substances released from tumor or immune response
= Fever, HTN, hypotension, hypoglycemia
Lymphatic system
Protects against disease/infection by filtering body fluids that leaked from putting back into the blood stream
Lymphocytes maturing
B lymphocyte = Bone marrow
T Lymphoctes = Thymus
Lymph nodes - filter the fluid in lymphatic system (neck, axillary, chest, abdomen, groin), swell during infections
Spleen - holds cells like macrophages
Thymus, bonemarrow, liver and tonsils as well
Hodkins lymphoma
Reed-Sternberg cells
- In lympho nodes
- Requires biopsy
Good prognosis
More common in men ages 15-30 and older than 55
Risk factors
EBV Virus, occupational virus, genetic, HIV
Clinical manifestation - weight loss, fatigue, weakness
- Fever
- No painful lymph nodes
Non-Hodkins lymphoma
More common, worse prognosis
Men older than 60
Risk factors
Genetic, toxin exposure, immunosuppressants/chemo
Same clinical manifestation
Frequent infection
Growth fraction
High growth fraction = tissues that have cells in active proliferation
Chemotherapy drugs more toxic
Low growth fraction = cells that are G0 phase, less receptive to cytotoxic cells
Chemotherapy barrier
1) Impossible to know when 100% of cancer cell kill
2) Drug resistance over time
3) Solid tumors respond poorly due to low growth fraction
4) Nearly impossible to completely kill every malignant cell
5) Cannot selectively target cancer cells (healthy cells die too)
6) Dosage limited due to toxicity
Chemo strategies
1) Intermittent therapy
- Chemotherapy at irregular interrvals to allow healthy cells to recover
- Only used when healthy cells regenerate faster than cancer cells
2) Combination therapy
- Usually 2 or more drugs used to
i) Reduce drug resistance
ii) Reduce toxic effects to healthy cells
iii) Increase cancer killing rate
3) Optimizing dosage schedules
4) Regional drug delivery
- If possible, direct chemo to area to reduce systemic effects
Neutropenia
ABC uunder 500 = Nadir
Nadir reached in 10-14 days
Begins to develop 2-3 days after dose
Must be monitored closely as signs of infection will be masked from no inflammation of WBC
NC
- LOW GRADE FEVER = emergency immediately
- Minimize contact with others, avoid crowds, hand washing
- Reverse isolation in hospital
- Reduce food w pathogens
