Neoplasia and Lung Cancer Flashcards
Distinguish the features of benign and malignant tumours - 4 key differences
1.) Degree of differentiation: How closely do the cell resemble a mature cell? The more differentiated the slower the rate of growth. Well differentiated = closely resemble tissue of origin. Extend determines how easily the location of the primary tumour can be identified.
2.) Rate of growth: > rate of growth = > accumulation of mutations = more difficult to treat
3.) Local Invasion
4.) Metastasis
Benign neoplasms (tumours)
Much better prognosis. Can be removed. Well differentiated, morphologically and functionally, closely resemble the origin tissue. Few mitoses. Grow slowly generally but can grow quickly under hormonal influence.
Malignant neoplasms (tumours)
Cancerous. Spread throughout the body - invade local tissues and then migrate to distant sites. The only type of tumour able to invade and metastasise. Generally grow quickly. Can be well differentiated or undifferentiated (anaplasm). This is due to dedifferentiation of mature cells or growth of stem cells. % of malignant cells = Tumour cellularity
Describe tumour differentiation
The process by which immature cells become mature cells with specialised functions. Well-differentiated tumours closely resemble their origin tissue. Also, normal cell receptors are present. They tend to grow at a slower rate.
Describe tumour invasion
Benign rarely invasive, often delineated by a fibrous capsule from host response and tumour. Malignant invade into blood vessels and local tissues. This is achieved by breaching the basement membrane. These pre-invasive tumours may be called intraepithelial neoplasm. Sees the breakdown of intercellular junctions (E-cadherin) –> BM and ECM degraded –> Attachment to novel ECM components –> Migration
Describe tumour angiogenesis
Excessive growth of neoplastic cells will cause development of a necrotic core, due to ischaemia. Necrotic cells in the centre of the tumour evoke inflammation which stimulate angiogenesis - creates nutrient supply for the tumour. Tumour cells and cells within the microenvironment also secrete factors to stimulate angiogenesis e.g. VEGF Antiangiogenic factors e.g. thalidomide
Describe tumour metastasis
Benign tumours compress adjacent tissues or release hormones, they cannot metastasise. Malignant tumours invade local tissues and then travel via the bloodstream or lymphatic system to new tissues. Tend to migrate to highly vascularised areas, such as the lungs, brain, adrenal glands, liver and bone.
Describe tumour progression
Initially the tumour is formed from a group of monoclonal cells. As division occurs and mutations arise a heterogeneous group of cells develops. Different divisions of cell are seen. Tumours change throughout growth. Personalised medicine aims to create the most suitable treatment as each tumour is so individual.
Describe tumour grading
Grade is found using a microscope, usually via a biopsy. Involves looking at the cells, looking at the number of cells (mitotic index), look how differentiated and pleomorphic they are, perform immune labelling. Allows the characteristics of the cells to be defined.
Describe tumour staging
Staging is decided using a scan. The TNM system is used: Tumour: Size, local invasion Nodes: Local of distal node involvement Metastasis: Can any be detected? A score in generated which helps direct treatment.
Understand the terminology relating to neoplasm
Neoplasm: New and permanent alteration of cell growth which persists upon removal of the stimulus.
Nomenclature: Benign epithelial neoplasms
~oma e.g. adenoma, papilloma Prefixed with tissue of origin e.g. renal adenoma
Nomenclature: Malignant epithelial neoplasms
Carcinoma, prefixed with cell type e.g. adenocarcinoma
Nomenclature: Benign parenchymal neoplasms (CN/muscle)
~oma e.g. chondroma, fibroma, lipoma, leiomyoma, rhabdomyoma, osteoma
Nomenclature: Malignant parenchymal neoplasms (CN/muscle
~sarcoma e.g. osteosarcoma
Lung Cancer
Primary lung tumours: 95% derived from bronchial epithelium - Metastatic from breast, colorectal, prostate, testicular and renal tumours
Lung cancer aetiology and epidemiology
- Most common cause of death from cancer in industrialised nations - Peak incidence between 50 and 60 years - Most likely killer in both men and women - Smoking and industrial carcinogens = main cause
Smoking and cancer
Statistics: 90% of lung cancer in smokers, passive smoking doubles risk, women more susceptible Clinical evidence: Progressive histological changes, heavy smokers 55x risk Experimental evidence: Genetic mutations
Types of lung cancer - Small cell lung cancer
Small cell carcinoma: Anaplastic cell. Highly malignant. Little cytoplasm. Necrosis
Types of lung cancer -Non-small cell lung cancer (NSCLC)
1.) Squamous carcinoma: Central, squamous cells, keratin, necrosis and cavitation. Established progression 2.) Adenocarcinoma: Central/peripheral glandular pattern, most common in women, non-smokers, < 45 yrs, bronchioalveolar carcinoma BAC 3.) Large cell carcinoma: Undifferentiated, pleiomorphic, adeno and squamous differentiation, poor prognosis
Dysplasia
A disordered cell growth usually seen in epithelial cells. Pre-neoplasia. May not always lead to cancer e.g. if the stimulus is removed the tissue may return to normal.
Distinguish the features of benign and malignant tumours
Rate of growth: Malignant tend to grow quicker Metastasis: Benign do not metastasise Invasion: Malignant invade (degrade BM) whereas benign tend to compress nearby structures Level of dedifferentiation/anaplasia: Malignant tend to have greater levels of anaplasia
Describe tumour differentiation, invasion, angiogenesis and metastasis
Tumour differentiation: Tumour cells lose the morphological and functional characteristics of the cell (anaplasia) Invasion: Destroy the BM (E-cadherins), novel adherence proteins form, invade the local tissue Angiogenesis: Stimulated by necrosis. VEGF, FGF promote the process. Allows supply of nutrients and removal of waste products Metastasis: Invasion into local tissues and into the blood stream. The tumour cells then establish a secondary tumour at a distant site
Describe tumour progression, grading and staging
Tumour progression: Dysplasia –> neoplasia Grading: Looks at the features of the cell, level of differentiation. Microscope Staging: TNM
Understand the terminology relating to neoplasia and the nomenclature of tumours
Neoplasia: Abnormal and excessive cell growth that persists even in the removal of a stimulus Epithelial tumours: Benign: -oma Malignant: Carcinoma Mesenchymal tissues (muscle/CT): Benign: - oma Malignant: Sarcoma Others: embryological origin = blastoma, totipotent cell = teratoma
Describe the 4 main types of lung cancer: aetiology, pathology, staging, treatment and prognosis
AMNA Small cell lung cancer: Oat cells. Anaplasia. < 5% 5-year survival. Highly malignant. Little cytoplasm, many mitoses. Necrosis. From neuroendocrine - can secrete hormones Non small cell lung cancer (3 types): 5 - 30 % 5-year survival rate 1. Squamous carcinoma: Central. Metaplasia. Rapidly dividing, aggressive, smokers, necrosis 2. Adenocarcinoma: Neoplastic gland tissue. Central/peripheral. Most common in women, non-smokers, < 45 yrs 3. Large cell carcinoma: Anaplastic, dysplastic. Poor prognosis
Distinguish small cell carcinoma from non-small cell carcinoma
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Outline the evidence linking smoking and lung cancer
90 % of lung cancer patients are smokers. Causes metaplastic changes in the structure of the respiratory epithelium May lead to a chain of mutation events.
Outline the cell cycle and it’s associated check points
Outline the progression of cancer
(e.g. hyperplasia)
Outline the features of SCLC and NSCLC
