Lung Cancer Flashcards
What are some risk factors of lung cancer?
- Age, peak 75-90
- Lower socioeconomic status
- Smoking history
- duration, intensity, when stopped
- Passive smoking
- Asbestos – exposure (plumbers, ship-builders, carriage workers, carpenters, etc) – risk up to x2
- Radon – e.g. silver miners in Germany late 19th century; 1950s uranium mining in Colorado
- Indoor cooking fumes – wood smoke, frying fats
- Chronic lung diseases (COPD, fibrosis)
- Immunodeficiency
- Familial/ genetic – several loci identified
Describe the pathogenesis of lung cancer
- Lung cancer may arise from all differentiated and undifferentiated cells
- The interaction between inhaled carcinogens and the epithelium of upper and lower airways leads to the formation of DNA adducts: pieces of DNA covalently bound to a cancer-causing chemical
- If DNA adducts persist or are misrepaired, they result in a mutation and can cause genomic alterations.
- These are key events in lung cancer pathogenesis, especially if they occur in critical oncogenes and tumour suppressor genes.
What are the different types of lungs cancers?
- Squamous cell carcinoma (~30% of cases).
– previously the most common
– originating from bronchial epithelium; centrally located [relates to smoking] - Adenocarcinoma (~40%)
– most common from 1980s onwards – low tar cigarettes, inhaled more deeply / retained longer
– originating from mucus-producing glandular tissue; more peripherally-locate - Large cell lung cancer (~15%)
heterogenous group, undifferentiated [difficult to treat because it’s not well understood]
1-3 often grouped together: non-small cell lung cancer (NSCLC)
- Small cell lung cancer (~15%)
originate from pulmonary neuroendocrine cells
highly malignant [most aggressive- grows v. quick BUT also responds to treatment quickly]
What mutations/ genes are targetted in the treatment of lung cancer?
“driver mutations”
MAIN ONE:
1. epidermal growth factor receptor (EGFR) tyrosine kinase
* 15-30% of adenocarcinoma
* more so in women, Asian ethnicity, never-smokers
OTHER GENES ALSO TARGETED:
2. anaplastic lymphoma kinase (ALK) tyrosine kinase
* 2-7% of non-small cell lung cancer
* especially in younger patients and never smokers
3. c-ROS oncogene 1 (ROS1) receptor tyrosine kinase
* 1-2% of non-small cell lung cancer
* especially in younger patients and never smokers
4. BRAF (downstream cell-cycle signalling mediator)
* 1-3% of non-small cell lung cancer
especially in smokers
What are the key symptoms of lung cancer?
(Or frequently asymptomatic- symptoms usually arise after the cancer has already advanced)
- Cough
- Weight loss
- Breathlessness
- Fatigue
- Chest pain
- Haemoptysis
What are the features of advanced/ metastatic disease
- Neurological features: (cancer spreads outside of thorax)
* focal weakness, seizures, spinal cord compression - Bone pain
- Paraneoplastic syndromes:
* clubbing, hypercalaemia, hyponatraemia, Cushing’s
What are the clinical signs of lung cancer?
- Clubbing (swollen fingers/ nails- non specific sign)
- Horner’s syndrome (constriction of pupil= droopy eye- usually associated with pancreas tumors)
- Cachexia (“wasting” disorder that causes extreme weight loss and muscle wasting, and can include loss of body fat.)
- Pemberton’s sign (Superior vena cava obstruction= when the patient lifts their arm’s there is reduced venous return due to the block- their face turns red)
What is wrong with lung cancer screenings as a diagnostic tool?
Diagnoses the lung cancer only after the patinet becomes symptomatic (too late)
What is the diagnostic strategy used for suspected lung cancer?
- Establish most likely diagnosis
- Establish fitness for investigation and treatment (e.g. if they’re too fragile, have irreversible cognitive decline, etc)
- Confirm diagnosis (tissue sample)
* specific type of cancer if considering systemic treatment (histologically) - Confirm staging (v. important as this will influence the treatment they receive)
What are some features seen on an X-ray of a lung cancer patient?
- Lung tumor
- Mass in the lungs
- Fluid “pleural effusion” could be caused by a mass
What are some features seen on a CT scan of a lung cancer patient?
- Irregular masses
- Lymph nodes infiltrated with carcinoma’s
What are some features seen on a PET scan of a lung cancer patient?
“radioactive drug to show up areas of your body where cells are more active than normal”
(definitive imaging for staging)
- Drug used= fluorodeoxyglucose (isotope of glucose)
- Goes to abnormal areas/ areas of rapid cell growth (tumors are areas that require high amounts of energy; attract the fluorodeoxyglucose)
Based on what features, do you choose the type of biopsy you conduct?
Choose method based on accessibility, availability and impact on staging
What are the types of biopsy you might consider to diagnose lung cancer? When would you choose each one?
- Bronchoscopy: [give sedation, place 5mm of flexible endiscope into airway, add saline +suck out+ study the sample, take out 5/6 pieces from lesions]
- for tumours of central airway
- where tissue staging not important - Endobronchial ultrasound and transbronchial-needle aspiration of mediastinal lymph nodes (EBUS [TBNA]) [look at the lymph glands not masses- checks for metastases]
- To stage mediastinum +/- achieve tissue diagnosis - CT-guided lung biopsy: [need to ensure patient has good lung function
- To access peripheral lung tumours
What are the different stages of lung cancer in accordance to IASLC (International Association for the Study of Lung Cancer) TNM 8th edition lung cancer staging system
TNM= tumor, nodes and metastases
Tx= tumour in sputum/ bronchial washings but not asses in imaging or bronchoscopy
T0= No evidence of tumor
T1= ≤ 3 cm surrounded by lung/ visceral pleura, not involving main bronchus
T2= >3 to ≤5 cm or involvement of main bronchus with carnia, regardless of distance from carina
T3= >5 to ≤7 cm in greatest dimension
N1,2 or 3
M1= distant metastases
