Lung Carcinoma

Write about Lung Carcinoma here.


• 19% of all cancers

• 27% of all cancer deaths

• 40, 000 cases/yr in the UK

• Incidence increasing in women

• Commonest cause of cancer death in Men, second (behind breast) in Women


Risk Factors:

Cigarette smoking - 30 a day = 30x risk.  On stopping smoking, excess risk decreases by 1/2 every 5 years.  About 26% of population smoke

• Passive smoking

• Asbestos

• Chromium

• Arsenic

• Iron oxides

• Radiation (Radon Gas)

• Increased incidence in patients with diffuse lung fibrosis such as cryptogenic fibrosing alveolitis or scleroderma

• "Scar Carcinomas" may occur in areas of focal fibrosis from previous TB


Pathology:

Two main types:

Small cell carcinoma (25%)

• Non-small-cell carcinoma (75%) which comprises

• Squamous cell carcinoma (30%)

• Adenocarcinoma (30%)

• Large-cell (undifferentiated) carcinoma (15%)

Alveolar Cell carcinoma (RARE <1%)


Small Cell (Oat Cell):

• Arises from neuroendocrine cells of the bronchial tree -> explaining its ability for ectopic hormone production

• Inappropriate ADH synrdome is most common => low Na, K and urea; serum osmolarity <280, and urine osmolarity >500

• ACTH (Cushing's)

• Highly malignant, grows rapidly (2x in 1/12), METASTASISES early


Squamous Cell Carcinoma:

• Commonest lung cancer

• Greatest tendency to cavitate

• Doubles in approx. 3/12

• Can lead to ectopic production of PTH (leading hypercalcaemia)


Adenocarcinoma:

• Incidence rising (2004 = 30%, 1998 = 20%)

• Often arise in periphery of lung, sometimes as 'scar carcinomas'

• Show the least relationship to smoking

• Doubles in approx. 6/12


Large-Cell (undifferentiated):

Show no squamous or glandular differentiation


Clinical:

• Tumours arising centrally often present with chest symptoms (e.g. haemoptysis), whereas peripheral tumours may grow silently until late in the course of the disease.

• Tumours > 1cm in diameter will be visible on CXR (30 doublings), symptoms typically appear after this.  By 40 doublings death is usually occurring.

• General symptoms:

• weight loss

• anorexia

• lethargy

• anaemia

• Specific symptoms:

• cough (80%)

• haemoptysis (70%)

• dyspnoea (60%)

• chest pain (40%)

• recurrent or slowly resolving pneumonia

• Signs

cachexia

• anaemia

clubbing

• HPOA (hypertrophic pulmonary osteoarthropathy, cuasing wrist pain)

• supraclavicular or axillary lymphadenopathy

Chest Signs

May be none

• Consolidation

• Collapse

Pleural effusion

Metastatic Signs:

• Bone tenderness

• hepatomegaly

• confusion

• fits

• focal CNS deficit

• cerebellar syndrome

• proximal myopathy

• peripheral neuropathy


Complications:

Local:

Direct invasion of mediastinum

• phrenic nerve palsy (diaphragm)

• recurrent laryngeal nerve palsy (particularly lower left side = vocal cord palsy with hoarseness and diminished cough reflex)

• obstruction of SVC, causing venous engorgement of upper body, facial swelling, distended pulseless jugular veins and enlarged collateral veins over chest and arms

Pancoast Tumour

• Pericarditis

• Rib erosion

• AF

Metastatic:

• Brain

• Bone (bone pain, anaemia, raised Ca)

• Liver (hepatomegaly)

• Adrenals (addisons = adrenal insufficiency

Endocrine:

• SIADH <- small cell

• Cushing's <- small cell

• PTH <- squamous cell


Metastasis:

To brain, bone, liver and adrenals


Tests:

• CXR - peripheral circular opacity, hilar enlargement, consolidation, lung collapse, pleural effusion, bony secondaries

• Sputum & pleural fluid cytology

• Bronchoscopy

• Percutaneous needle biopsy for peripheral tumours

• CT for staging

• Radionuclide for metastases

• Lung function tests


Treatment:

Non-small cell

• Sx resection is treatment of choice for peripheral tumours with no metastatic spread (approx 25%) i.e. for Stage II

• Curative radiotherapy is alternative in patients with inadequate respiratory reserve or inoperable tumours


Small Cell

Almost always already disseminated by presentation

• May respond to chemotherapy

• cyclophosphamide, doxorubicin, vincristine, etoposide or cisplatin combos


Palliation

Radiotherapy used for symptomatic relief 

• Endobronchial therapy (stenting etc.)

• Pleural drainage/pleurodesis

• Drug therapy - analgesia, antiemetics, corticosteroids etc.



Prognosis:


Overall 5 year mortality = 90%


Non-small cell:

50% 2 yr survival (without spread)

• 10% 2 yr survival (with spread)

Small cell:

Median survival is 3/12 without treatment

• Median survival is 1 1/2 years with treatment


Stage I -> 50-60% 5 yr survival

Stage II -> 30% 5 yr survival

Stage IIIa-> 20% 5 yr survival

Stage IIIb-> 0% 5 yr survival

Stage IV -> 0% 5 yr survival


Other Lung Tumours:

Alveolar cell carcinoma

Bronchial adenoma - rare, slow-growing. 90% carcinoid, 10% cylindromas.  RX = Sx

Carcinoid tumour

Hamartoma - rare, benign tumour.  CT = lobulated mass with flecks of cavitation.  Often excised to exclude malignancy

Mesothelioma