Week 11 - Neoplasia 4 Flashcards
What are the most common cancers?
- Lung is most common
- Breast
- Prostate
- Bowel carcinomas
What are the most common cancers in children?
- Leukaemias
- CNS tumours
- Lymphomas
What are the leading causes of cancer deaths?
- Pancreatic cancer
- Then lung cancer
Which cancer has the best 5 year survival rate?
Testicular cancer (98%)
Which factors should be considered when determining which individuals will have a favourable outcome for malignant neoplasm?
- Age
- General health
- Tumour stage
- Tumour grade
- Tumour site
- Availability of effective treatments
What is the TNM staging system?
- T: size of primary tumour
- – Typically expressed as T1 through to T4
- N: extent of regional node metastasis
- M: denotes the extent of distant metastatic spread
- The T, N and M status are then converted into a stage from I to IV
What do the tumour stages generally mean?
- Stage I: early local disease (T1, 2; N0; M0)
- Stage II: advanced local disease (T3,4; N0; M0)
- Stage III: regional metastasis (any T; N1-3; M0)
- Stage IV: advanced disease (any T; any M; M1)
What is the Ann Arbor staging?
Tumour staging used for lymphomas
- Stage I: lymphoma in a single node region
- Stage II: 2 separate regions on 1 side of the diaphragm
- Stage III: spread to both sides of the diaphragm
- Stage IV: diffuse or disseminated involvement of 1 or more extra-lymphatic organs
What is the point of tumour staging?
It is a powerful predictor of survival
- A measure of the malignant neoplasm’s overall burden
What is Dukes’ staging?
A system used for colorectal carcinoma
- A = invasion into, but not through the bowel wall
- B = invasion through the bowel wall
- C = involvement of lymph nodes
- D = distant metastases
What is meant by tumour grading?
Grading describes the degree of differentiation of a neoplasm
- Important for planning treatment and estimating prognosis
What do the tumour grades typically mean?
- G1 = well differentiated
- G2 = moderately differentiated
- G3 = poorly differentiated
- G4 = undifferentiated/anaplastic
What is the Bloom-Richardson system?
A grading system used for breast carcinomas
- It assesses tubule formation, nuclear variation and number of mitoses
What are the different treatments for cancer?
- Surgery
- Radiotherapy
- Chemotherapy drugs
- Hormone therapy
- Targeted molecular therapies
How is surgery used as a treatment for cancer?
- Mainstay of treatment for most cancers
- There is adjuvant or neoadjuvant treatment
What is adjuvant treatment?
It is given after surgical removal of a primary tumour to eliminate subclinical disease
What is neoadjuvant treatment?
It is given to reduce the size of a primary tumour prior to surgical excision
How is radiation used as a treatment for cancer?
- Kills proliferating cells by triggering apoptosis or interfering with mitosis
- Focused on the tumour with shielding of surrounding healthy tissue
- Given in fractionated doses to minimise damage to normal tissues
- X-rays or other types of ionising radiation are used
- It kills rapidly dividing cells
- High dosage causes either direct or free-radical induced DNA damage
- – Detected by the cell cycle check points, triggering apoptosis
- – Double stranded DNA breakages cause damaged chromosomes that prevent M phase from completing correctly
How are chemotherapy drugs used as a treatment for cancer?
- Affect proliferating cells
- Several classes of chemotherapy agents exist
- – Antimetabolites mimic normal substrates involved in DNA replication
- – Alkylating and platinum-based drugs cross-link the 2 strands of the DNA helix
- – Antibiotics act in several ways
How is hormone therapy used as a treatment for cancer?
- Relatively non-toxic treatment for certain malignant tumours
- Selective oestrogen receptor modulators bind to oestrogen receptors
- – Prevents oestrogen from binding
- – Used to treat hormone receptor-positive breast cancer
- Androgen blockade is used for prostate cancer
How can targeted molecular therapies be used as a treatment for cancer?
Herceptin
- Can block HER-2 signalling
- 25% of breast cancers have overexpression of the HER-2 gene
How can tumour markers be used?
Can be used in diagnosis and monitoring of tumour burden during treatment and follow-up
- Can be hormones (e.g. human chorionic gonadotrophin is released by testicular, non-seminomatous tumours)
- Can be antigens (e.g. carcinoembryonic antigen is normally only seen in embryonic tissue but cancer expresses it again)
- Can be specific proteins (e.g. prostate-specific antigen is released by prostate carcinoma)
- Can be mucins/glycoproteins
Describe the breast cancer screening program in the UK
Women aged 47-73 are screened every 3 years
- Use a mammogram
Describe the colorectal cancer screening program in the UK
Adults aged 60-69 are screened every 2 years
- They are sent a home screening kit to give a stool sample, which is then tested
Describe the cervical cancer screening program in the UK
- Women aged 25-49 are screened every 3 years
- Women aged 50-65 are screened every 5 years
- Use a PAP smear
