11 Respiratory tract:neoplastic disease Flashcards
What this lecture will cover
Lung carcinomas Aetiology Classification Clinical features Staging Lung metastases Pleural tumours Metastases Malignant mesothelioma
Lung tumours
Benign and malignant tumors may arise in lung
Vast majority (90% to 95%) are carcinomas (arising from lining epithelium)
About 5% are bronchial carcinoids (neuroendocrine)
2% to 5% are mesenchymal and other miscellaneous neoplasms including sarcomas and lymphomas
Lung carcinomas
2nd most common cancer in UK Incidence increasing in females, decreasing in males Age 40-70 years Male > female 5 year survival 8% (men), 9% (women)
Risk factors
Smoking Industrial hazards High dose ionising radiation Uranium Asbestos Radon Silica Diesel exhaust/air pollution Family history Immunodeficiency
Smoking
Statistical evidence
87% of lung carcinoma in active smokers/recently stopped smoking
10 fold ↑ risk for average smokers, 60 fold ↑ risk for heavy smokers (>40/day for several yrs)
3000 non smokers die of lung ca/year – passive smoking
Cigar/pipe - ↑ risk, but less so than cigarettes
Clinical evidence
Linear correlation between exposure to cigarette smoke and epithelial changes (metaplasia, dysplasia, CIS, invasive carcinoma)
Also associated with carcinoma of the mouth, pharynx, larynx, oesophagus, pancreas, cervix, kidney and bladder
Clinical details
Presenting complaint Cough (75%) Weight loss (40%) Chest pain (40%) Dyspnoea (20%)
May present with symptoms of metastases
Local extension of tumour within pleural cavity, to pericardium
Spread to tracheal, bronchial and mediastinal nodes found in most cases; nodal involvement average >50%
Most common distant spread adrenals (>50%), liver (30-50%), brain (20%), bone (20%)
Paraneoplastic syndromes
Ectopic hormone secretion by tumour
Incidence 1-10% of all lung cancer patients
Hormones involved include:
Antidiuretic hormone (ADH) – hyponatraemia
Adrenocorticotrophic hormone (ACTH) – Cushing syndrome
Parathormone, parathyroid hormone-related peptide, prostaglandin E, cytokines – hypercalcaemia
Calcitonin – hypocalcaemia
Gonadotropins – gynaecomastia
Serotonin and bradykinin – carcinoid syndrome
Lung carcinoma
Staging – TNM staging
Treatment – Surgical
Chemotherapy – targeted therapy for EGFR mutation
Radiotherapy
Prognosis: 15% overall 5-year survival
(48% for cases detected when still localised)
adenocarcinoma, SCC – slightly better prognosis, tend to remain localised longer
Lung Carcinoma – Staging - TNM
T’ - Primary tumour size/degree of invasion?
‘N’ – Lymph nodes positive or not ?
‘M’ – Distant metastases or not ?
Classification
Small cell carcinoma (20-25%)
Non-small cell carcinoma
Squamous cell carcinoma (25-40%)
Adenocarcinoma (25-40%)
Large cell carcinoma (10-15%)
Combined carcinoma
Small cell carcinoma
Strong relationship to smoking – 1% occur in non smokers
Occur in major bronchi and at periphery
Rapidly invade bronchial wall and parenchyma; early lymphatic and blood-borne spread
Therefore mostly incurable by surgery
Most responsive to chemotherapy – but worst prognosis as relapses early
HISTOPATHOLOGY: small, tightly packed, darkly stained ovoid tumour cells (resemble oats – also termed oat cell carcinoma)
Small cell carcinoma
Cells with little cytoplasm
Finely granular nuclear chromatin (“salt + pepper”)
Absent or inconspicuous nucleoli
Can be pure or combined (with any other non-small cell type)
Other histological features
Nuclear molding
Crush artifact
Necrosis
High mitotic index
Squamous cell carcinoma
Most commonly affects men
Closely correlated with smoking history
Arises close to hilum, usually in area of squamous metaplasia (due to cigarette smoke)
HISTOPATHOLOGY: well differentiatied resembles stratified squamous epithelium; characterised by keratin formation and/or intercellular bridges
Adenocarcinoma
Most common type in women and non-smokers (but >75% found in smokers)
Tend to be peripherally located
Grow more slowly than SCC but metastasize early and widely
Sometimes associated with scarring e.g. healed TB
HISTOPATHOLOGY: well differentiated have obvious glandular elements; 80% contain mucin
