Cancer screening

Question 1

c. Why is breast cancer one of the main cancers that is amenable to screening? (13 marks)

Answer 1

i. Breast cancer is the second most common cause of cancer in women and has high morbidity and mortality
ii. There is evidence that a pre-malignant stage exists, called ductal and lobular in situ carcinoma
iii. Screening tests are simple and non-invasive as they include a mammogram and a physical examination to ensure compliance of targeted population
iv. The physical examination and mammogram are sensitive and specific enough to detect these pre-cursor lesions and decrease false-negatives and false-positives
v. Evidence that early detection poses a good prognosis on the patient
vi. Cost is justified – the cost spent should is proportional to the lives saved and prevention of expensive treatment

Question 2

97. How do you process a mastectomy and what sections are taken?

Answer 2

1. Confirm patient identification and look at patient history
2. Take a measurement of the skin and the axillary tail separately
3. Use the axillary tail and skin to orient the specimen.
4. Remove the axillary tail and dissect out the lymph nodes. Place a safety pin in the upper outer quad-rant.
5. Note any Skin or nipple involvement of the tumour
6. Turn the breast over, and ink the specimen in different colours to main orientation e.g. superior por-tion in red and inferior in green etc.
7. Serial section the specimen into thin slices
8. Note the location and size of any tumours.
9. Submit at least two (ideally five) sections of tumor, at least two sections from each quadrant, and two sections of the biopsy site. Also submit a section of the nipple and of the skin. Lymph nodes should be entirely submitted for histologic evaluation.
   Microscopic:
   - Microscopic size of the tumor and report if these measurements concordant
   - In situ or infiltrating carcinoma - if the lesion contains both in situ and infiltrating carcinoma, identify which proportion of the lesion is in situ, and what proportion is infiltrating
   - Does in situ carcinoma extend away from the main tumor mass?
   - Histologic type and grade of the in situ or infiltrating carcinoma
   - Lympho/vascular invasion

Question 3

98. What are the criteria for cancer screening?

Answer 3

• High morbidity and mortality
• Evidence that a pre-malignant stage exists and a good understanding of disease history
• Incidence of malignancy is high
• Screening tests are simple and non-invasive to ensure compliance of targeted population
• Tests must be sensitive and specific to decrease false-negatives and false-positives
• Evidence that early detection poses a good prognosis on the patient
• Cost is justified – the cost spent should be proportional to the lives saved and prevention of expensive treatment

Question 4

99. What problems are encountered when screening?

Answer 4

• Screening tests are often non-invasive and have an increase risk of false-positives or false negatives due to low specificity and low-sensitivity
• Target population may change and may be difficult to establish
• Some tests are expensive and cannot be used on the whole population
• Requires at least 70% attendance of target population

Question 5

101. What lesions can be detected by mammography?

Answer 5

Calcified lesions are detected by mammography, this is often associated with ductile in situ carcinoma or invasive ductile carcinoma and less commonly with lobular in situ carcinoma.

Question 6

100. What follow-up investigations are made if a pathology report of LBC is indicative of mild dyskaryosis?

Answer 6

• If the patient is under 30 years of age, she is followed-up after 6 months since mild dyskaryosis tends to regress in young adults. However, the doctor might order a colposcopy if deemed necessary
• If the patient is over 30 years, the liquid based cytology vial is sent for HPV DNA testing to determine if the HPV subtype is high-risk or low-risk. If high-risk a colposcopy is performed.

Question 7

103. Why aren’t tumour markers used for screening?

Answer 7

Tumour markers are not used as screening markers as they are non-specific, they can be elevated in benign conditions and several different malignant conditions, therefore, they are used when there is clinical suspicion of malignancy or when diagnosed for prognosis, staging, monitoring disease progression and treatment etc.