• Created by: Emmatjies
  • Created on: 13-05-20 10:26

Aetiology of cancer

Cancer is nearly always caused by abnormalities in genetic material that are either inherited or there was an error in the splicing of the genes in DNA replication.

Cancer is a loss of normal growth including a loss apoptosis.

Carcinoma in situ is the earliest stage of carcinoma; it is only present in tissues where it started and has not spread ti any near tissues.

Can be Macroscopic or microscopic.

Macroscopic- Requires imaging and surgery- They meausre size, consistency, shape, capsule an appearance.

Microscopic- Cell pattern, differention, biochemistry, neoplasia.Requires, imaging and biopsy 

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Effect on Host

Angiogenesis- The formation of new blood vessels.

Neuroendocrine effects- Production of hormones, antibodies, hypercoaguabillity. (neuroendocrine cells that reciev neuronal input and release hormones into the blood.)

Paraneoplastic effects- Paralysis of phrenic nerve and recurrent laryngeal nerve (para neoplastic effects are rare disorders triggered by an altered immune reponse)

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Metastatic spread

Spread via:

  • Direct- Invade neighbouring tissues
  • Blood- Through baxton's plexus
  • Lymphatic system- Lymphatic permeation, Retrograde spread
  • Transcoelomic-Shedding of cells into serous cavities.
  • Implantation- Natural passageways, surgical incision.

Cancer chooses the path of least reisistance:

  • Invade tissue spaces
  • Into epithelial cavities
  • Baxton's plexus - Valve-less venous blood vessels.
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Classification of tumours

  • Carcinomas- Arise from epithelial tissue
  • Sarcomas- Arise from connective tissue
  • Lymphomas- Arise from lymphomas
  • Adeno- Gland
  • Chrondo- Cartilage
  • Erythro- Red blood Cell
  • Haemangio- Blood vessel
  • Hepato-Liver
  • Lipo- Fat
  • Lympho-Lymph
  • Melano- Melanocyte
  • Myelo- Bone marrow
  • Mylo- Muscle
  • Osteo- Bone
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Lung cancer


  • Smoking
  • Genetics
  • Passive smoking
  • Lacks of physical activity

Either small cell lung cancer (20%) or Non-smal call carcinoma (80%)


  • Haemoptysis
  • Cough
  • Stridor
  • Weightloss
  • Lethargy
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Small cell Lung cancer

Highly malignant

No cure

Mets often spread to brain

Tumours double in size every month

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Non-small cell carcinoma

Also known squamous cell carcinoma

Responsible for 80% of lung carcinomas

Causes mucosal changes in large airway

Present in larger bronchi

It is undetectable on a CXR until airway obstruction occurs


  • Lobar collapse
  • Enlarged hilar collapse
  • Pleural effusion
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Why stage a cancer?

To aid the clinician in planning treatment

To give an indication of prognosis

To assist in the evaluation of test results

To facilitate exchange of info between treatment centres.

To continue to investigate cancer.

Use TNM (tumour node mets) and dukes scoring system.

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Benign VS Malignant

  • Movable
  • No ulceration
  • Unattached
  • Growth by expansion
  • Slow growth
  • NO vascularisation
  • Distinct radiogrpahic appearance-clear borders
  • Hard
  • Ulcerations
  • Fixed to overlying skin
  • Growth by invasion
  • Rapid growth
  • Vascularisation
  • Indistinct radiographic appearances
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