lung cancer

Question 1

how do you pathologically diagnose cancer?

Answer 1

• histopathology uses clinical method
• distribution of tumour, gross appearances, number, shape and size
• growth pattern at margin of tumour
• histological type, prognostic and predictive features
• all requires multidisciplinary approach

Question 2

what are the main histological types of lung cancer?

Answer 2

• small cell (AKA oat cell) carcinoma

- non small cell carcinoma

Question 3

what cancers come under ‘non-small cell carcinoma’?

Answer 3

• squamous cell carcinoma
• adenocarcinoma
• undifferentiated/large cell carcinoma
• mixed and others

Question 4

what are the key characteristics of small cell carcinoma?

Answer 4

• widespread bulky disease
• small, dark, delicate cells with little cytoplasm
• ‘salt and pepper’ chromatin in the nuclei
• azzopardi effect

Question 5

what are the key characteristics of squamous cell carcinoma?

Answer 5

• central origin often

- cigarette smoke provokes squamous metaplasia, then dysplasia of bronchial epithelium

Question 6

what is squamous carcinoma thought to arise from?

Answer 6

squamous metaplasia and dysplasia of bronchial epithelium

Question 7

what might adenocarcinoma begin from?

Answer 7

malignant cells lining alveolar spaces

Question 8

what are some key characteristics of adenocarcinoma?

Answer 8

• peripheral

- contains fibrous tissue and shows variable differentiation which correlates with prognosis

Question 9

what do you look for to distinguish between squamous cell carcinoma and adenocarcinoma?

Answer 9

looking for specific proteins

eg - TTF1 expression is typical of adenocarcinoma

Question 10

how do you determine therapy of lung adenocarcinoma?

Answer 10

• molecular pathology
• adenocarcinomas are subdivided according to key driver mutations
• EGFR mutations may be targeted with tyrosine kinase inhibiting agents
• ALK fusion proteins may be targeted with ALK Tki
  PD1/PD-L1
• precious tissue is prioritised for testing to permit rational therapy

Question 11

what are the patterns of spread of lung cancer?

Answer 11

• local and direct spread: adjacent lung, intrapulmonary metastasis, pleura and plueral cavity
• lymphatic: lymphatics within lung, lymph nodes (hilar, mediastinal)
• systemic spread: liver, bone, brain, adrenal

Question 12

how do you make a diagnosis?

Answer 12

• multidisciplinary effort
• clinical features, imaging
• histological type: small cell and non small cell carcinoma, adenocarcinoma
• confirm bu looking for proteins
• prognostic and predictive molecular therapy
• increasingly diagnosis is made on tiny specimens obtained by minimally invasive procedures