Respiratory - lung cancers

Question 1

Histology of lung cancer

Answer 1

Non small cell lung cancer (80%) - made up of

• Adenocarcinoma (40%) - can cause gynaecomastia
• Squamous cell carcinoma (20%) - associated with clubbing, typically central (others are peripheral)
• Large cell carcinoma (10%)
• Others (10%)

Small cell lung cancer - usually central, paraneoplastic syndromes

Question 2

Small cell lung cancer features

Answer 2

contain neurosecretory granules that can release neuroendocrine hormones.

This makes SCLC responsible for multiple paraneoplastic syndromes.

Question 3

Signs and symptoms of lung cancer

Answer 3

SOB
Cough
Haemoptysis
Clubbing
Weight loss
Recurrent pneumonia
Lymphadenopathy - often supraclavicular nodes first

Question 4

Investigations for suspected lung cancer

Answer 4

CXR - first line
Staging CT (CAP) with contrast (or PET-CT)

Biopsy (either via bronchoscopy (EBUS guided?) or percutaneously) and histology

Question 5

Findings that may be seen on CXR in lung cancer

Answer 5

Hilar enlargement

“Peripheral opacity” – a visible lesion in the lung field

Pleural effusion – usually unilateral in cancer

Collapse

Question 6

What is the first line investigation for line cancer?

Answer 6

CXR

Question 7

What are the 2ww referral criteria for lung cancer?

Answer 7

CXR findings suggest lung cancer

Aged over 40 with unexplained haemoptysis

Question 8

When to offer an urgent CXR (i.e. within 2 weeks)

Answer 8

If they are over 40 with two or more of these unexplained symptoms:

• Persistent cough
• Fatigue
• SOB
• Chest pain
• Weight loss
• Appetite loss

Only one of these symptoms needed if they have ever smoked

Question 9

Treatment of lung cancer

Answer 9

Advise smoking cessation

NSCLC:

• Can be resected if limited to a single area e.g. lobectomy
• Radiotherapy can be curative if early cancer
• Adjuvant chemotherapy for surgery

SCLC:

• Usually a combination of radiotherapy and chemotherapy e.g. cisplatin
• Worse prognosis than NSCLC (usually metastatic by the time of diagnosis)
• Can consider surgery for people with early-stage SCLC (T1-2a, N0, M0)

Palliative treatment can include stents or debulking to relieve bronchial obstruction caused by lung cancer

Question 10

Extra pulmonary manifestations of lung cancer

Answer 10

Recurrent laryngeal nerve palsy - hoarse voice (caused by cancer pressing on or affecting the recurrent laryngeal nerve as it passes through the mediastinum)

Phrenic nerve palsy - diaphragm weakness/SOB

SVC obstruction - presents with facial swelling, difficulty breathing and distended veins in chest/neck and Pemberton’s sign

Also airway obstruction in lung Ca progression

Horner’s syndrome - triad of ptosis, anhidrosis and miosis
- caused by pancoast tumour in lung apex which presses on the sympathetic ganglion

Question 11

Paraneoplastic syndromes in lung cancer

Answer 11

SIADH - due to ectopic ADH secretion by SCLC (presents with hyponatraemia)

Cushing’s - ectopic ACTH secretion by SCLC

Hypercalcaemia - ectopic PTH secretion from a squamous cell carcinoma

Limbic encephalitis - SCLC causes the immune system to make antibodies to tissues in the brain, specifically the limbic system, causing inflammation in these areas. This causes symptoms such as short term memory impairment, hallucinations, confusion and seizures. It is associated with anti-Hu antibodies.

Question 12

What is Lambert-Eaton Myasthenic syndrome?

Answer 12

a result of antibodies produced by the immune system against small cell lung cancer cells.

These antibodies also target voltage gated calcium channels in motor neurons

Leads to weakness - especially in proximal muscles but also:

• Intraocular muscles - causing diplopia
• Levator muscles - ptosis
• Pharyngeal muscles - slurred speech and dysphagia

Patients may also experience dry mouth, blurred vision and dizziness due to autonomic dysfunction

Reduced tendon reflexes, these show post-tetanic potentiation (muscle strength improves on repetitive movement)

Question 13

Mesothelioma description, risk factors, prognosis

Answer 13

Lung malignancy affecting the mesothelial cells of the pleura

Linked strongly to asbestos

Long latent period between exposure and developing cancer

Poor prognosis

Chemotherapy can improve survival but usually palliative

Question 14

Common lung cancer metastases sites

Answer 14

Brain, Bone, Liver, Adrenals

Question 15

Hypercalcaemia in Lung cancer can be caused by

Answer 15

Ectopic PTH secretion by squamous cell carcinoma

Bony metastases (would also tend to have raised ALP due to increased bone turnover)

Question 16

Causes and treatment of SVCO

Answer 16

Malignancy e.g. lung Ca, Lymphoma
Aortic aneurysm
Mediastinal fibrosis
Goitre
SVC thrombosis

Treatment:

• Endovascular stenting
• Radical chemo or chemo-radiotherapy instead in the case of cancers may be of benefit