Lung onco and tech

Question 1

What is the aetiology?

Answer 1

Cigarette smoking,

• Asbestos ~ synergy with smoking
• Radon
• Metals; arsenic, beryllium, cadmium, chromium, haematite, nickel and tin mining
• Polycyclic aromatic hydrocarbons
• Ionizing radiation

Question 2

What is the pathology?

Answer 2

Majority of lung malignancies are bronchogenic (in the bronchial epithelium)

• Out of the bronchogenic malignancies 80% are Non-small cell (NSC) while 20% are small cell
• The NSC lung cancers are comprised of squamous cell carcinomas which make up 30% of lung cancer cases while adenocarcinomas make up 50% of lung cancer cases

Question 3

What are the symptoms?

Answer 3

• Primary lesion: Cough, Breathlessness, Haemoptysis, Chest pain
• Intrathoracic Spread: pleural or pericardial effusion, hoarseness of voice, brachial plexus involvement, compression of SVC
• Distant Metastasis: pain (bone mets); weakness and weight loss; headaches, seizures, neurological symptoms (cerebral mets)
• Paraneoplastic: Set of symptoms due to the cancer but not caused by a systemic rather than local effect of cancer cells. Due to either immune response to the cancer or substances secreted by the cancer; SIADH, Hypercalcemia, Clubbing and hypertrophic pulmonary osteopathy

Question 4

Treatment for early stage NSCLC?

Answer 4

• Surgery +/ Adjuvant Chemo: Tumour must be resectable + acceptable lung & cardiac function + no other comorbidities that would preclude surgery
• Radical Radiation Therapy (50Gy/20#, 60Gy/30#): If surgery is refused, or comorbidities that preclude surgery + acceptable lung function
• Observe or Palliative RT: If poor lung function

Question 5

What are the assesment for late stage NSCLC?

Answer 5

– Volume of disease 
– Lung function 
– Co-morbidities 
– Fitness for chemo 
– Symptoms

Question 6

Fractionation NSCLC?

Answer 6

60Gy/30# (2G/f, 5 days a week for 6 weeks)

Question 7

What are the palliative fractionations for NSCLC?

Answer 7

• With chest symptoms and poor performance status; 16Gy/2# or 10Gy/1#
• With chest symptoms and good performance status; 32Gy/12#
• No symptoms and poor performance status; 16Gy/2# or 10Gy/1#

Question 8

Fractionation for SABR?

Answer 8

• Ablative doses of radiotherapy. BED >100Gy

- Usually in <5 fractions eg 54Gy in 3 fractions

Question 9

Treatment for NSCLC?

Answer 9

• Chemotherapy is the mainstay of treatment – 4 x cisplatin/etoposide
• Thoracic RT – à increase local control – Two meta-analyses have demonstrated that the addition of thoracic RT to CT results in a small statistically significant improvement in survival

Question 10

Fractionation for NSCLC?

Answer 10

• Alternated fractionation schedule may be beneficial due to the rapidly growing nature of SCLC
• Hyperfractionation; 45Gy/30# (1.5Gy p.d for 3 weeks), 45Gy/25# (1.8Gy 5 weeks)

Question 11

What is PCI? And why is it used?

Answer 11

Prophylactic Cranial Irradiation (PCI)
• High incidence of cerebral metastases in SCLC
• Brain sanctuary site for chemotherapy, hence argument for use of PCI

Question 12

Fractionation for PCI?

Answer 12

PCI Treatment

• Volume: Whole brain
• Technique: R and L lateral fields
• Dose: 25Gy in 10 fractions

Question 13

How is respiratory motion overcome?

Answer 13

1. Motion Encompassing; CT imaging that includes the entire range of motion, these include, Slow CT, Inhilation and exhalation breath hold CT, and 4DCT
   • 4DCT:
2. Motion Compensation;
   • Respiratory Gating: Imaging and delivery of XRT during a portion of the breathing cycle, the “gate
3. Motion Suppression: Breath hold methods
   • Deep-inspiration breath-hold (DIBH);
   • Active- Breathing control (ABC)

Question 14

Side effects of Tx?

Answer 14

• Cough; - avoid dry air and smoking
  
  • use extra pillows
  • rest between activities
• Dyspnoea- shortness of breath; - avoid triggers eg. Wind, pollen, smoke
  - use relaxation techniques
  - physio help
• Pneumonitis- inflamed lung tissue; - late effect- up to 3-6 months following XRT
  - medical treatment necessary
• Oesophagitis- heartburn; - small meals
  - soft, bland foods
  - avoid temperature extremes
  - avoid alcohol and coffee
  - meds: viscous xylocaine etc.
• Skin reaction; - mild soap
  - no talc or deodorant on tx area
  - avoid very hot/cold water
  - no shaving, perfume on tx area
  - apply appropriate moisturiser 3x day

Fatigue; - frequent rests
- gentle exercise