List the most common cancers
Breast, lung, prostate and bowel carcinomas account for over half of all new cancer
What cancers are most common in children
- In children, leukaemia, central nervous system tumours and lymphomas common
Which cancers have the highest and lowest 5 year survival rates
- High 5 year survival rates - testis, malignant melanoma, breast, prostate
- Low 5 year survival rates - pancreas, lung, brain, stomach, oesophageal
Which cancers have the highest death
Highest deaths - lung, breast, bowel, prostate
What factors should you consider when predicting cancer outcome
Age, general health status, tumour site, tumour type, trade, tumour stage and availability of effective treatment
What does tumour stage measure
Tumour stage measures malignant neoplasm’s overall burden
Explain the TNM staging system
- TNM staging system - assess tumour stage
- T - size of primary tumour
- T0 - T4
- N - extent of regional node metastasis
- N0 - N3
- M - extent of distant metastatic spread
- M0 or M1
- TNM status converted into a stage from I to IV
- Stage I - early local disease (T1-2)
- Stage II - advanced local disease (T3-4)
- Stage III - regional metastasis (N≥1)
- Stage IV - advanced disease with distant metastasis (M=1)
- T - size of primary tumour
Explain the Ann Arbour staging system
- Ann arbour staging for lymphoma
- Stage I - lymphoma in a single node region
- Stage II - two separate regions on same side of diaphragm
- Stage III - spread to both sides of the diaphragm
- Stage IV - diffuse or disseminated involvement of one or more extra-lymphatic organs such as bone marrow or lungs
Explain the Duke’s staging system
- Dukes staging for colorectal cancer
- Stage A - invasion into but not through bowel
- Stage B - invasion through bowel wall
- Stage C - Involvement of lymph nodes
- Stage D - distant metastases
What does tumour grade measure
Tumour grade describes degree of differentiation of neoplasm
Explain how tumour grading occurs
- Grading of neoplasms not standardized, unlike staging
- G1 - well differentiated
- G2 - moderately differentiated
- G3 - poorly differentiated
- G4 - undifferentiated or anaplastic
- System used for colorectal carcinoma and squamous cell carcinoma
Explain the Bloom-Richardson grading system
- Bloom-Richardson system describes tumour grade in breast cancer
- Assesses tubule formation, nuclear variation and number of mitoses
Explain how tumour grading is used
- Tumour grading important in planning treatment and estimating prognosis in certain types of malignancies
- Soft tissue sarcoma, primary brain tumours, lymphoma, breast cancer, prostate cancer
List cancer treatment methods
- Can be treated by surgery, radiotherapy, chemotherapy, hormone therapy and targeting specific molecular alterations
- Immune system targets showing promise
What is the main type of cancer treatment
Surgery main treatment for cancers but treatment also depends on type of cancer and stage
Explain radiotherapy
- Radiotherapy - kill proliferating cells either by inducing apoptosis or interfering with mitosis
- Use X-ray radiation to kill rapidly dividing cells particularly in G2 of cell cycle
- Either direct or free radical induced DNA damage in G2 detected by cell cycle checkpoints, which initiate apoptosis
- Double stranded DNA breakages cause damaged chromosomes that prevent M phase from completing properly
- Healthy cells shielded with metal
- Given in fractionated doses - bigger differential effect, reduce impact on healthy cells
Explain chemotherapy
- Antimetabolites - mimic normal substrates involved in DNA replication
- Compete with normal metabolites in DNA synthesis pathways
- Eg. Fluorouracil
- Alkylating and platinum based drugs cross link the two strands of DNA helix
- Damaged DNA leading to apoptosis
- Eg. Cisplatin, cyclophosphamide
- Antibiotics act in different ways
- Doxorubicin inhibits DNA topoisomerase, which is needed for DNA synthesis
- Bleomycin causes double-stranded DNA breaks
- Plant-derived drugs blocks microtubule assembly and interferes with mitotic spindle formation
- Eg. Vincristine
- All these treatment target proliferating cells but are non specific - side effects such as loss of hair follicles
Explain hormone treatment
- Non toxic treatment for certain malignant tumours
- Selective oestrogen receptor modulators (SERMs) bind to oestrogen receptors preventing oestrogen from binding
- Eg. Tamoxifen
- Used to treat hormone receptor-positive breast cancer
- Androgen blockade used for prostate cancer
- Selective oestrogen receptor modulators (SERMs) bind to oestrogen receptors preventing oestrogen from binding
Explain how oncogenes can be targeted for treatment
- Target specific mutant proteins using probes
- Drugs that block immune checkpoints are a new emerging area of treatment
- Eg. A quarter of breast cancers have overexpression of Her-2 gene and Herceptin can block Her-2 signalling
- Eg. Chronic myeloid leukaemia shows a chromosomal rearrangement creating an abnormal ‘Philadelphia’ chromosome in which an oncogenic fusion protein is encoded
- Imatinib inhibits the fusion protein
What is curative treatment
- Curative treatment - cure initial diagnosis (disease free) but can have micrometastases
- Typically surgery
What is adjuvant treatment
Given after removal of primary tumour to eliminate subclinical disease
What is neoadjuvant treatment
Given to reduce size of primary tumour prior to surgical excision
Describe the use of tumour markers in diagnosis and monitoring of disease
- Various substances released by cancer cells into circulation
- Useful for monitoring tumour burden during treatment and follow up
- Include hormones, oncofetal antigens, specific proteins, mucin/glycoproteins
- Oncofetal - made. In feral tissues but re-expressed in cancer tissue
Discuss the use of cancer screenings
- Look for early signs of disease
- Earlier detect of cancer lowers the spread and increase chance of cure
