Cancer 3

Question 1

What are 7 effects that a tumour can have on its host?

Answer 1

1. Disfigurement
2. Mechanical interference with normal function e.g. prostate tumour –> urinary difficulty, midbrain tumour –> blocked aqueduct –> hydrocephalus, metastisis in lymphnodes –> obstruction of superior vena cava
3. Interference with function of organ or tissue e.g. cancer cells replacing liver parenchyma
4. Discontinuity of surface (ulcer): due to invascion, necrosis and ulceration. Can cause bleeding/haemorrhage or infection.
5. Weight loss - cancer cachexia - due to an increased metabolic demand combined with decreased food intake
6. Function of neoplastic cells e.g. paraneoplastic effects (e.g. osseous - finger clubbing), endocrinopathies
7. Psychological disturbances: brain metasteses can affect behaviour, also depression due to diagnosis

Question 2

What is one pro and one con of tasting for Prostate Specific Antigen?

Answer 2

Pro: early detection in men who otherwise would not have been tested
Con: over-diagnosis in some men resulting in unnecessary costly and invasive treatments/further testing

Question 3

What are 4 ways/tests used for diagnosing cancer?

Answer 3

1. Screening programmes e.g. mammography, self-examination pap smear etc.
2. Clinical history, physical examination + diagnostic tests - patient presents with a problem and first thing is doctor tries to exclude malignancy
3. Grading + staging of cancer
   - Grading = microscopic, degree of differentiation + number of mitoses
   - Staging = more important, CT scans, X-rays etc., size and extent of spread of the primary tumour
4. Diagnostic techniques for cancer - HISTOLOGICAL DIAGNOSIS = main one used

Question 4

What are the 5 ways in which tumour cells or tissue may be examined?

Answer 4

1. Standard histological techniques e.g. paraffin section
2. Immunohistochemical techniques e.g. using antibodies that are specific for certain antigens
3. Chromosomal analysis e.g. Philadelphia chromosome in CML
4. Molecular diagnosis - examination of the genes being expressed by the tumour
5. Flow cytometry - used for quantitiation of antigens and cell surface antigens - used for leukemias + lymphomas