Interactive Tutorial: Carcinoma Of Lung

Question 1

Lung cancer

Answer 1

• Most common cancer for male
• Highest mortality
• Leading cause of cancer death in the world —> Only slight decrease in mortality over the years

Why deadly:
1. Late presentation (Asymptomatic)
2. Early metastasis (via rich Lymphatic network)
3. Advanced stage —> Inoperable —> Poor survival rate

Question 2

Lymphatic drainage of lung cancer

Answer 2

A lot of patient has LN metastases at initial presentation —> Lung cancer considered as a “systemic” disease:
1. Hilar LN (60-75%)
2. Mediastinal LN (40-50%)
3. Supraclavicular LN (2-15%)

(From CPRS L2, 3, 5:
Superficial LN (subpleural lymphatic plexus)
—> Deep LN (pulmonary —> bronchopulmonary —> tracheobronchial —> paratracheal)
—> Bronchomediastinal lymphatic trunk
—> Thoracic duct (left) + Right lymphatic duct (right)
—> Brachiocephalic vein
—> SVC)

Question 3

Risk factors for Lung cancer

Answer 3

Modifiable:
1. Smoking (90% of lung cancer for male patients)
2. 2nd hand smoke
3. Ionising radiation (e.g. radon)
4. Occupational exposure (asbestos, silica, arsenic, chromium, nickel)
5. Indoor / Outdoor pollution

Unmodifiable:
6. Age
7. Male
8. Family history
9. Acquired lung disease (e.g. IPF)

Question 4

Types of Lung cancer

Answer 4

1. Non-small cell lung cancer
   - Adenocarcinoma (40%)
   - SCC (25%)
   - Large cell carcinoma (10%)
2. Small cell lung cancer
3. Mixed histology
   - Adeno + SCC
   - Small cell + Non-small cell

Question 5

Symptoms of Lung cancer

Answer 5

1. Asymptomatic (mostly)
   - very often tumour have existed for some time before discovered
   - incidental finding e.g. CXR for pre-op / another condition
2. Local involvement of bronchus
   - **Cough (80%)
   —> most common early symptoms
   —> **new / altered cough pattern
   —> with ***purulent sputum if there is secondary infection

• ***Haemoptysis (70%)
  —> repeated episodes of scanty haemoptysis / blood-stained sputum in chronic smokers —> highly suggestive of lung cancer —> should be investigated
• **Dyspnea (60%)
  —> uncommon due to large lung reserve
  —> occlusion of large bronchus —> **collapsed lung / ***pleural effusion
• ***Pleural pain
  —> malignant invasion of pleura / infection distal to a tumour (recurrent and fail to resolve)

3. Regional systems
   - Direct invasion of pleura / ribs
   - **Severe pain of shoulder / medial aspect of arm (∵ Pancoast’s tumour involving lower part of Brachial plexus (C8, T1, T2))
   - **Horner’s syndrome (∵ Sympathetic ganglion)
   - **Hoarseness (∵ (Left) RLN palsy causing unilateral vocal cord paresis)
   - **Paralysis of diaphragm (∵ phrenic nerve —> Raised hemidiaphragm)
   - Dysphagia (∵ esophagus)
   - ***CVS symptoms
   —> AF, Tamponade, Pericarditis, Pericardial effusion
   —> SVC obstruction (SVCO)
   —> Early morning headache + facial congestion + edema involving upper limb + distension of jugular + chest vein
4. Systemic
   - Spread to chest wall / mediastinum
   - **Distant metastasis: Bone pain, Pathological fractures, Brain metastasis causing focal neurological symptoms, epilepsy, headache
   - **Paraneoplastic (small cell lung cancer)
   —> SIADH
   —> ACTH secretion (Cushing’s syndrome)
   —> HyperCa
   —> Gynaecomastia
   - **Neurological: Sensory polyneuropathy, myelopathy
   - **Hypertrophic pulmonary osteoarthropathy
   - Finger clubbing
   - Nephrotic syndrome
   - DIC
   - Hypercoagulopathy
   - Thrombophlebitis migrans

Question 6

P/E of Lung cancer

Answer 6

Normal unless significant bronchial obstruction / tumour spread to pleura / mediastinum

1. Wheeze (Bronchial obstruction)
2. Stridor (Main airway obstruction)
3. Hoarseness (RLN palsy)
4. Dullness to percussion (Pleural effusion)
5. Absent breath sounds at lung base (Diaphragmatic palsy)
6. SVCO signs (Pemberton’s sign)
7. Horner’s
   - Miosis
   - Partial ptosis
   - Loss of hemi-facial sweating (anhydrosis)

Question 7

Investigations of Lung cancer

Answer 7

1. No specific tumour marker (?CEA)
2. CXR
3. CT thorax with contrast
4. Biopsy
   - Sputum cytology (low yield)
   - Bronchoscopy (BAL / Forceps)
   - Transthoracic biopsy (FNAC)
   - Electromagnetic navigation bronchoscopy (can get to peripheral small airway)
   - Video assisted thoracic surgery (VATS) +/- Lung resection
5. PET scan
   - FDG-18, enhanced glucose metabolism of lung cancer cells
   - SUVmax >2.5 ***suggestive of malignancy
   Pros:
   - Non-invasive
   - Assess pulmonary nodules, LN
   - Distant metastasis e.g. liver, bone

Cons:
- Brain and heart very high background glucose metabolism (need CT contrast / MRI brain to rule out metastasis)
- High false positive: e.g. Other inflammatory disease, **TB (∴ just a guide for biopsy, need **histological proof)

Mediastinal LN staging
6. Mediastinoscopy
- incision just above sternal notch
- risk of injury to great vessels

7. EBUS (Endobronchial USG) / EUS

Question 8

Staging of Lung cancer

Answer 8

Purpose:
1. Treatment guidance
2. Prognosis indicator

TNM staging (AJCC 8th edition):
- Stage 1, 2: Early —> Operable
- Stage 3a: Variable (small tumour with LN involvement / large tumour without LN)
- Stage 3b, 4 (metastasised): Advanced —> Systemic treatment

Prognosis (5 year survival):
- Stage 1: >60%
- Stage 2: 30-50%
- Stage 3a: 15-30%
- Stage 3b: 3-6%
- Stage 4: <1%

Question 9

Treatment of Lung cancer

Answer 9

Small cell lung cancer:
- Chemo + RT
- Surgery limited role ∵ early metastasis (unless very localised disease: surgery —> chemotherapy)

Non-small cell lung cancer:
- Surgery (offer best chance of survival particularly for early stage of disease)
- Chemo/RT, Targeted therapy (for advanced disease, overall poor prognosis)

Types of resection:
1. Wedge resection
2. Lobectomy (lobe of lung)
3. Sleeve lobectomy (lobe of lung + segment of bronchus removed (if involvement of bronchus) —> reconnect remaining lung to main bronchus)
4. Pneumonectomy (whole side of lung)

Operability:
1. Tumour factor
- Stage
- Anatomy

2. Patient factor
   - Tolerate surgery?

Question 10

General assessment of patient factors

Answer 10

1. Detailed medical history + examination
2. Baseline blood test
3. ***Cardiovascular assessment
   - ECG
   - Echocardiogram
   - Cardiac catheterisation
   —> cardiac complications are 2nd most common cause of perioperative morbidity + mortality after thoracic surgery
   —> indicated for any suspicious symptoms (e.g. angina)
4. ***Lung function test
   - Spirometry test, FEV1
   - DLCO
   - Exercise test
   —> 6 minute walk
   —> shuttle walk test (able walk >400m)
   —> stairs climbing test (5 FOS: pneumonectomy, 3 FOS: lobectomy)
   —> formal cardiopulmonary exercise tests (CPET): VO2 max
5. Performance status
6. Nutrition status

Question 11

FEV1, DLCO

Answer 11

• Predicted value according to body size, age, gender, race
• Absolute value + Predicted percentage
  —> Calculate ***Predicted post-op FEV1 (ppoFEV1) or DLCO (ppoDLCO)

ppoFEV1 = Pre-op FEV1 x (number of segments left after resection / 19 (total number of lung segments))

• A patient is considered to be at increased risk for lung resection with ppoFEV1 or ppoDLCO ***<40% predicted
• Major respiratory complications were only seen in subgroup with ppo <=40%
• ppo <=30% required post-op mechanical ventilatory support

Question 12

Cardiopulmonary exercise tests (CPET)

Answer 12

• VO2max: maximum amount of O2 in mL, one can use in 1 min / kg of body weight during exercise (unit = mL/kg/min)
• VO2max >20: not at increased risk for complications / death
• VO2max <15: increased risk of peri-operative complications
• VO2max <10: very high risk for peri-operative complications / death

Question 13

Surgical approach to Lung cancer

Answer 13

Nowadays nearly all thoracic surgery can be performed using VATS approach

Traditional open surgery:
- Surgical trauma
- Severe wound pain
- Poor early post-op lung function
- Long hospitalisation
- Poor cosmesis