L28: Population Screening – Lung

Question 1

What are the risk factors for lung cancer?

Answer 1

• tobacco smoking
• asbestos – 5x increased risk
• occupational exposure – uranium, radon, arsenic, chromium
• diffuse lung fibrosis – 10x increased risk
• chronic obstructive pulmonary disease

Question 2

What is the major risk factor of lung cancer?

Answer 2

tobacco smoking – implicated in 90% of cases

• squamous cell lung cancer: 11x (men), 15x (women)
• small cell lung cancer: 10x (men), 25x (women)
• large cell lung cancer: 7x (men), 8x (women)
• lung adenocarcinoma: 4x (men and women)

Question 3

Describe the epidemiology of lung cancer.

Answer 3

• lung cancer is a leading type of cancer
• leading cause of cancer mortality worldwide – accounting for ~20% of all cancer deaths
• one of the most diagnosed cancers in British Columbia
• an estimated 26,600 Canadians were diagnosed – 20,900 died in 2015
• in Canada, the incidence of lung cancer is currently higher in men than in women

Question 4

Why should we screen for lung cancer?

Answer 4

lung cancer symptoms normally do not appear until the disease is already at an advanced stage and spread

• detect disease before it manifests clinically
• poor prognosis → 90% of people with lung cancer die of the disease
• 5-year survival for stage I lung cancer is 66-82%
• from 2006-2008, overall 5-year relative survival for people diagnosed with advanced lung cancer was 17%

Question 5

Why is it important to detect disease before it manifests clinically?

Answer 5

• earlier diagnosis may result in better response to treatment
• more treatment options
• better chance of success

Question 6

Who should be screened for lung cancer?

Answer 6

best for those who are at high-risk for lung cancer, and who are not experiencing any symptoms

• 55-74 years of age
• currently smoking or have smoked in the past < 15 years ago
• have a smoking history of 20 pack-years or more

Question 7

What imaging is used to screen for lung cancer?

Answer 7

low-dose CT (LDCT)

• low-dose CT scan is a safe and effective way to screen for lung cancer, and can pick up much more than a chest x-ray can
• LDCT every year for three consecutive years

Question 8

How do we determine the probability of malignancy of a lung nodule?

Answer 8

sub-solid nodules → higher probability of malignancy

• Li et al. compared malignant and benign nodules in a study – prevalence of malignancy was 59% for non-solid nodules, 48% for part-solid nodules, and 11% for solid nodules
• growth rate of non-solid nodules tends to be considerably slower than solid lesions

Question 9

What is the main method to obtain lung lesion specimens?

Answer 9

imaging-guided biopsy

• different techniques modalities – ultrasound, CT, fluoroscopy
• complications: pneumothorax, parenchymal pulmonary hemorrhage

Question 10

What are 2 radiology procedures for lung cancer?

Answer 10

• CT-guided biopsy of nodules/masses
• CT-guided microcoil insertion

Question 11

Describe CT-guided biopsy of nodules/masses.

Answer 11

• complications include bleeding, or air entering the lining around the lung and compressing it
• very rarely require transfusion or hospital stay

Question 12

Describe CT-guided microcoil insertion.

Answer 12

• helps surgeon with localizing nodule during resection (using metal detector intra-operatively to find the one section that needs to be taken out) – reduces surgical time
• benefit of focal ‘wedge’ cut out rather than removing the whole lobe/lung – less invasive surgery