7. tumour diagnosis and prognosis Flashcards
main techniques used in the investigation and diagnosis of tumours
symptoms
signs: physical exam
- tumour markers
- biopsy
- histology
- imaging
Tumour Markers
- Certain tumours liberate products that can be detected in blood/urine/CSF samples, thereby acting as tumour markers.
These may aid diagnosis but may also be used to follow up therapy when blood levels become increased, often before imaging can detect tumour recurrence
Tumour Biopsy
- Virtually every site in the body can be biopsied
- Tissue samples are acquired for examination
- Techniques used vary according to site and suspected diagnosis
Needle biopsy: inserted into organ
Endoscopic biopsy- inserted into hollow organ
Curettage: scrape out
Biopsy Handling
Fix in formalin solution for routine histology, special stains and immunohistochemistry
Fix in glutaraldehyde for electron microscopy
Send fresh for cytogenetics, tumour genetics
Diagnostic Cytology
- Examination of cells in tissue fluids or exfoliated from surfaces (Fine Needle Aspiration)
- diagnosis of malignancy (shed cells would be malignant)
- Useful for screening – main example is cervical cytology programme
Cervical cytology
Cluster of cells with prominent nuclei, overlap each other, different chromatin pattern
Further test for malignancy or change in growth
two assessments made during histology to predict behaviour
- Analysis of the degree of differentiation and growth pattern of the tumour.
- Evaluation of how far a tumour has spread.
Tumour Stage
- The size of a primary tumour
- The degree to which it has locally invaded
- The extent to which it has spread by distant metastasis
Staging Systems - TNM
tumour spread
lymph nodes
metastasis
- The stage of a tumour is generally the most important indicator of likely prognosis and of appropriate therapy
- Advanced stage tumours (extensive spread) may require aggressive treatment
- Early stage tumours (localized) may be treatable by relatively conservative measures
Duke stage for colorectal cancer
Grade of Tumour:
The degree of differentiation of tumour cells relative to normal tissue of origin
- Variation in size and shape of constituent cells of the tumour (pleomorphism)
- The proportion of cells containing mitotic figures (mitotic index)
Low grade tumours are slow growing and have a good prognosis
High grade tumours are fast growing and have a poor prognosis
- Tubule formation
- Nuclear pleomorphism
- Mitotic counts
1-3: 1 is good
three examples of tumour markers and outline their use in evaluating tumours
HCG – human chorionic gonadotrophin from tumours with trophoblast elements. If high something wrong with placenta.
AFP - alpha fetoprotein. Liver cancer, germ cell tumours. (should go down with effective treatment, released by germ cells)
- Sudden spike
- Primitive cells should only be in non adults
PSA – prostate-specific antigen from carcinoma of the prostate (prostate inflammation-low, benign-higher and malignant-very high)
List the main modes of therapy for tumours
- Surgery
- Remove entire tumour
- Debulk tumour- other treatments can work better
- Ease cancer symptoms (relieve pressure)
- Radiotherapy
- Targets DNA of cancer cells to stop growing and death
- Radiation is aimed at the tumour so difficult to use in metastatic cancer
- Chemotherapy
* Targets cells during mitosis stage
* The faster cell is dividing, more likely it will target that cell
Tumour Prognosis
- Remission- no evidence of disease (signs and symptoms reduced)
- Disease – free survival
- Five year survival
- Ten year survival
- Tumour with an excellent prognosis
thyroid
tumours moderate prognosis
kidney, prostate, cervix, breast
