Lung Cancer

Question 1

Discuss the epidemiology of lung cancers?

Answer 1

Lung cancers cause the most amount of cancer related deaths worldwide, 35’000 deaths per year in the UK. It has both a very high prevalence mostly due to the worldwide smoking habits and a very low 5-year survival rates.

Question 2

Discuss the relationship between smoking, lung cancers and cancers generally

Answer 2

Smoking causes 90% of lung cancer deaths in men, 80% in women and 20% in non-smokers. And 1 third of all cancer deaths.

Question 3

What other risk factors are there for lung cancer?

Answer 3

Asbestos usually only in presence of smoking too

Radon in Cornwall from mining or indoor exposure

Other occupational carcinogens such as chromium, nickel and arsenic
Genetic/familial factors.

There are around 5000 cases a year for non-smokers.

Question 4

Describe the T part of the TNM staging system for lung cancer

Answer 4

T – Size and position of tumour
• T1 – Cancer contained within lung (<3cm diameter)
• T2 – Cancer has grown (3-7cm diameter): Into main bronchus <2cm from the carina, Into the visceral pleura or made part of the lung collapse
• T3 – Cancer has grown (> 7cm diameter): invading chest wall, mediastinal pleura, diaphragm, pericardium or Complete lung
• T4: Cancer invading mediastinum, heart, major blood vessel, trachea, carina, oesophagus, spine, recurrent laryngeal nerve or Cancer nodules in more than one lobe of the same lung

Question 5

Describe the N and M part of the TNM staging system for lung cancer

Answer 5

N – Lymph node involvement
• N0 – No cancer in lymph nodes
• N1 – Cancer in lymph nodes nearest the affected lung
• N2 – Cancer in lymph nodes in mediastinum, on the same side
• N3 – Cancer in lymph nodes on the opposite side of the mediastinum / supraclavicular lymph nodes

M staging refers to number of metastases. M0 = no metastases, M1a = localised intrathoracic spread M1b = disseminated extrathoracic spread.

Question 6

Above which stage are lung cancers considered non-operable, and again for palliative care only?

Answer 6

Anything above stage 2 is considered non-operable whilst anything above stage IIIA is considered only for palliative care.

Question 7

Where do lung cancers commonly metastasise too?

Answer 7

Other lung, pleura, pericardium, liver, adrenal gland and brain.

Question 8

What tests are done allowing us to stage lung cancers?

Answer 8

Pet scan – shows neoplasia activity. Can also shows sarcoidosis or pneumonia activity. But useful to pick up metastasis throughout the body. This is in comparison to the CT scan. Can also undertake MRI, ECHO, Bone scan. Tissue sampling is done via bronchoscopy, cervical lymph node fine needle aspiration, pleural fluid aspiration and CT guided biopsies.

Question 9

What are the symptoms of lung cancer, and for both regional and distant metastasis?

Answer 9

Primary Tumour: cough, dyspnoea, wheezing, haemoptysis (coughing up blood), lung infection, chest/shoulder pain, weight loss and lethargy/malaise or no symptoms at all most commonly.

Regional metastases: bloated face (SVC obstruction), hoarseness (LRLNPalsy), dyspnoea (anaemia and pleural or pericardial effusions), dysphagia due to oesophageal compression and chest pain form parietal pleural movement.

Distant metastases: bone pain and fracture, CNS symptoms such as headaches, double vision and confusion etc.

Question 10

What metabolic symptoms are common with lung cancer?

Answer 10

Metabolic symptoms – thirst, hypercalcaemia, constipation such as hypercalcaemia and seizures because of hyponatraemia.

Question 11

What signs are there for lung cancer?

Answer 11

Signs: Cachexia (general weakness and wasting), pale conjunctiva, cervical lymphadenopathy, Horners Syndrome, consolidation, signs of pleural effusion, muffled heart sounds, liver enlargement skin metastases, neurological signs and the most common – no signs.

Question 12

What are paraneoplastic syndromes?

Answer 12

Paraneoplastic syndromes associated with Lung cancer are the presence of symptoms or disease due to the presence of cancer in the body, but not due to the local presence of cancer cells.

Question 13

Describe some common paraneoplastic syndromes?

Answer 13

They are mediated by humoral factors (cytokines and hormones) secreted by tumour cells, or the immune response against tumour cells.
• Endocrine related: Hypercalcaemia, Cushing’s syndrome and SIADH
• Neurologically related: encephalopathy, peripheral neuropathy and Eaton-lambert syndrome
• Haematological: anaemia and thrombocytosis
• Cutaneous: dermatomyositis
• Skeletal: finger clubbing

Question 14

What are the most commo lung cancer types?

Answer 14

Non-small cell lung cancer: squamous cells carcinoma 40%, adenocarcinoma 35%and large cell carcinoma 5%. These tend to present with a 2/3 chance of them being inoperable
Small cell carcinoma – 12% present with a 75% chance of metastasis at diagnosis and so has a much worse prognosis.
Rare tumour such as carcinoid – 5%

Question 15

What are the 4 molecular markers for different lung cancers?

Answer 15

Molecular markers: EGFR mutations, ALK mutations, KRAS mutations and PD1 mutations

Question 16

What treatment options are available for lung cancers?

Answer 16

Surgery – mostly for non-small cell carcinomas providing the best chance of cure but only 20-25% are usually operable.

Radiotherapy – with lung cancer this is usually only with palliative intent

Combination chemotherapy: Small cell – potentially curative, non-small cell – modest survival increase but mostly symptoms control,

Neoadjuvant therapy – pre-surgery and Adjuvant – post surgery.

Combination therapy – combining chemo and radiotherapies – potentially curative

Biological targeted therapies based on mutational analysis of markers – promising

Palliative care – symptom control and analgesia.

Question 17

What are the markers of an addiction?

Answer 17

Markers of addiction are: use despite knowledge of harmful consequences, craving during abstinence, failure of attempts to stop and withdrawal symptoms during abstinence. Cigarette smoking is an addiction and a chronic relapsing disorder.

Question 18

Describe the physiology of Nicotine?

Answer 18

Acts on nicotinic acetylcholine receptor stimulating dopamine release. This results in satisfaction associated with smoking. Following chronic nicotine exposure ACh enters upregulated state increases affinity and functional sensitivity to an agonist. A drop in nicotine levels leads to craving and withdrawal. 1-2 puffs of a cigarette causes binding to 50% of ACh receptors. ACH receptors take between 5-12 weeks to desensitise after the last cigarette.