Lung Cancer - Radiology and Staging

Question 1

How should you interpret a CXR?

Answer 1

In conjunction with clinical findings.
Always compare with previous CXRs if available, to assess for change.
Does my interpretation make sense?

Question 2

What is a key feature of central lung carcinoma?

Answer 2

Lobar collapse which fails to resolve in 2-3 weeks, in a >45yr old smoker.

Question 3

Where can you find lesions on a CXR?

Answer 3

Can often be subtle.
Compare with previous films.
Review areas - hila, apices, diaphragm, behind the heart.

Question 4

What is the clinical history of lung cancer?

Answer 4

Increasing SOB in a smoker.
History of pulmonary fibrosis.
Recent haemoptysis.
Confirm an intrapulmonary lesion via CXR.

Question 5

What must be evaluated in a CT for lung cancer?

Answer 5

Size, shape, atelectasis, borders, density, solid vs non-solid, and growth.
Use a dynamic contrast enhancement (>25HU).

Question 6

What is the difference between a pulmonary mass and a pulmonary nodule?

Answer 6

Both are opacities in the lung, with no mediastinal adenopathy or atelectasis.
PM - >3cm.
PN - <3cm.

Question 7

What are the causes of solitary pulmonary nodules or masses?

Answer 7

Lung cancer - age, smoking Hx.
Metastases - previous Hx of breast or renal carcinoma.
Benign lung neoplasm (carcinoid, hamartoma).
Infection (bacterial, fungal, TB).
Vascular haematoma, arteriovenous malformation (AVM).

Question 8

How is staging of lung cancer determined?

Answer 8

Clinical history and examination.
Performance status.
Pulmonary function.

Question 9

What is TNM staging?

Answer 9

T - how big it is, how far it has spread, and position.
N - whether cancer cells have spread into the lymph nodes.
M - whether the tumour has metastasised.

Question 10

What tests are done for TNM?

Answer 10

All use CT and PET-CT.
T - bronchoscopy.
N - mediastinoscopy, EBUS/EUS.
M - bone scan.

Question 11

What is Tx, T0, and Tis?

Answer 11

Tx - the primary tumour cannot be assessed.
T0 - no evidence of a primary tumour.
Tis - carcinoma in situ.

Question 12

What is T1?

Answer 12

Tumour <3cm in greatest dimension.
Surrounded by lung or visceral pleura.
No bronchoscopic evidence or involvement of the main bronchus.

Question 13

What is T1a, T1b and T1c?

Answer 13

T1a - minimally invasive carcinoma.
Tumour <1cm in greatest dimension.
T1b - tumour <2cm in greatest dimension.
T1c - tumour <3cm in greatest dimension.

Question 14

What is T2?

Answer 14

Tumour 3-5cm with any of the following -
Involves the main bronchus, but not the carina.
Invades the visceral pleura.
Associated with atelectasis or obstructive pneumonitis that extends to the hilar region involving part or all of the lung.

Question 15

What is T2a and T2b?

Answer 15

T2a - tumour 3-4cm in greatest dimension.
T2b - tumour 4-5cm in greatest dimension.

Question 16

What is T3?

Answer 16

Tumour 5-7cm or one that directly invades any of the following -
Chest wall (including superior sulcus tumours).
Phrenic nerve.
Parietal pericardium.

Or, separate tumour nodule(s) in the same lobe as the primary tumour.

Question 17

What is T4?

Answer 17

Tumour >7cm or invades any of the following -
Diaphragm, mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, oesophagus, vertebral body, or carina.

Or, separate tumour nodule(s) in a different ipsilateral lobe.

Question 18

What is FDG PET?

Answer 18

Functional imaging.
Uses 18F-FDG, a labelled glucose analogue.
Expensive and has limited availability in the UK.

Question 19

What are the N stages?

Answer 19

N0 - no regional LN metastases.
N1 - ipsilateral peribronchial, hilar or intrapulmonary nodes including by direct extension.
N2 - ipsilateral mediastinal, subcarinal.
N3 - contralateral mediastinal, contralateral hilar, scalene or supraclavicular.

Question 20

What are the M stages?

Answer 20

M0 - no distant metastasis.
M1 - distant metastasis.

M1a - separate tumour nodule(s) in a contralateral lobe; or tumour with pleural or pericardial nodules, or malignant pleural or pericardial effusion.
M1b - single distant metastases.
M1c - multiple distant metastases.

Question 21

What is PET-CT?

Answer 21

Assesses chest wall or mediastinal invasion.
Discloses metastases and other pathology not detected by other means (unexpected metastases in 10-20%).
Excludes metastases where structural imaging is abnormal.

Question 22

What are the benefits and limitations of PET-CT?

Answer 22

Non-invasive.
Can have false negative and positive results.
Cost.

Question 23

How is survival rate linked to TNM staging?

Answer 23

As T and N increases, survival decreases.
If M = 1, then survival drops to 1%.

Question 24

How is tissue diagnosis done in lung cancer?

Answer 24

Bronchoscopy and EBUS.
Percutaneous image guided biopsy.
Fluoroscopy / CT / US guided.
Mediastinoscopy to sample anterior/mediastinal nodes.
Video assisted thoracoscopic surgery (VATS).
Explorative thoracotomy.

Question 25

How are the size of lymph nodes linked to metastases?

Answer 25

The bigger the lymph nodes, the greater the percentage of metastases.