Lung Cancer Flashcards
Why is lung cancer so significant across the world?
it is common (13% of all cancer cases in UK)
It is the most common cause of cancer death worldwide
What is the prognosis of lung cancer like?
POOR PROGNOSIS
- 1 year survival - 32%
- 5 year survival - 9.5%
- 10 year survival - 4.9%
SCLC has a worse prognosis than NSCLC
What is the difference between cytology and histology?
cytology involves looking at cells
histology involves taking biopsies and looking at pieces of tissue
In lung cancer, what types of cytology technique are carried out?
- bronchial brushing and washing
- bronchoscopy
- fine needle aspiration - this is CT guided
need to get close to the tumour in order to make a good quality diagnosis, so sputum is no longer used
What histological techniques are used in tissue diagnosis of lung carcinoma?
- endoscopic biopsy
- bronchoscopy
- cutting needle biopsy
- CT guided
- thoractomy (including VATS)
- wedge/lobar/whole lung biopsy
- resection +/- intra-operative frozen section
Why is intra-operative diagnosis not conducted?
there is a higher risk of having a false or false negative result as the morphology of the tissue is poor
What are the two main types of lung carcinoma?
what are the sub-types?
non-small cell carcinomas (NSCLC):
- squamous carcinoma
- adenocarcinoma
- undifferentiated large cell carcinoma
small cell carcinoma (SCLC)
mixed types are not uncommon
What is the normal composition of the bronchial epithelium?
the normal bronchus is lined by pseudostratified columnar epithelium
with ciliated and mucus-secreting (goblet) cells
How do irritants, such as cigarette smoke, affect the bronchial epithelium?
they cause the epithelium to undergo a reversible metaplastic change
the cells go from pseudostratified columnar to stratified squamous type which may keratinise (more protective)
What happens if one of the squamous metaplastic cells of the bronchia epithelium undergoes irreversible genetic changes?
irreversible genetic changes involve a series of sequential somatic mutations of oncogenes/tumour suppressor genes/apoptosis genes
this loses control of normal cell growth and produces the first neoplastic cell
What happens to the bronchial epithelium once the first dysplastic cell has occurred?
the neoplastic cell proliferates more successfully than the metaplastic cells
the neoplastic clone replaces the metaplastic cells, producing dysplasia
What happens to cells in squamous carcinoma?
neoplastic cells breach the basement membrane producing invasive squamous carcinoma
invading neoplastic cells infiltrate lymphatic and blood vessels to produce metastases in lymph nodes and distant sites
What are the characteristics of squamous carcinoma?
- resembles squamous epithelium
- cells are linked by desmosomes
- there may be keratinisation
- it occurs more centrally than peripherally
- it secretes parathyroid hormone related peptide that causes hypercalcaemia
90% of cases occur in smokers
What are the characteristics of adenomacarcinoma?
- arises from glandular cells
- occurs equally in the centre and the periphery
- less well defined dysplastic phase called ‘atypical alveolar cell dysplasia’
80% of cases occur in smokers
Which is worse, SCLC or NSCLC?
SCLC
it is the most malignant on the spectrum of lung neuroendocrine tumours
99% of cases occur in smokers
What type of lung cancer is shown?
non small cell carcinoma
there is a lot of variability in the nuclei (some are dark and some are pale)
there is random growth distribution
What type of lung cancer is shown?
small cell carcinoma
the nuclei are more crowded together and darker as there is less cytoplasm present
