1.02 - Lung Cancer Flashcards
Risk factors for lung cancer.
- tobacco smoking (incl. second hand smoke)
- asbestos
- outdoor air pollution
- COPD
- tuberculosis
- exposure to radiation
How does smoking tobacco cause lung cancer?
Tobacco carcinogens (e.g. nitrosamines and polyaromatic hydrocarbons) form DNA adducts (ie. DNA and carcinogens bound together).
These DNA disturbances cause mutations within tumour suppressor genes, interrupting repair and cell cycle regulation mechanisms.
What are the two broad divisions of lung cancer?
- small cell lung cancer (SCLC) (15%)
- non-small cell lung cancer (NSMLC) (85%)
Mesothelioma and neuroendocrine tumours make up a minority of diagnoses.
Divisions of NSCLC.
- squamous cell carcinoma
- adenocarcinoma
- large cell carcinoma
Which type of lung cancer is most closely associated with smoking?
Squamous cell carcinoma - non small cell lung cancer.
Prognosis of squamous cell carcinoma of the lung.
Slow growing tumour
Which type of lung cancer is most closely associated with non-smokers?
Adenocarcinoma - precursor is atypical alveolar hyperplasia.
Prognosis of adenocarcinoma of the lung.
- faster doubling time than SCC
- early metastasis
- worse prognosis than SCC
Prognosis of large cell carcinoma.
- caviating lesions
- early metastasis (often to GI tract)
- prognosis similar to adenocarcinoma
Features of SCLC.
- 10-15%
- lesions usually centrally located
- aggressive tumour with distant metastasis at time of diagnosis
- more responsive to NSCLC to chemotherapy and radiotherapy, but prognosis is still poor
Signs and symptoms of lung cancer.
- cough (>3 weeks)
- shortness of breath
- wheeze
- chest pain
- hoarseness of voice
- headache
- swelling of face, arms and/or neck
- arm, shoulder and/or neck pain
- fever
- night sweats
- weight loss
- decreased appetite
Why does dyspnoea occur in lung cancer?
- mass effect of tumour pressing on the bronchi or trachea
- tumour induces fluid to flow in around the lungs, heart or chest cavity
Why does wheeze occur in lung cancer?
- mass effects of the tumour pressing on the bronchi or trachea
Why does hoarseness of voice occur in lung cancer?
- mass effects of tumour compressing the recurrent laryngeal nerve that innervates the vocal cords
Why does swelling of the head / neck / arms occur in lung cancer?
- mass effect of tumour compressing the superior vena cava
What are the common sites of metastasis for lung cancer?
Lung cancer mets to A BBL:
- adrenal glands
- bones
- brain
- liver
Diagnostic workup for lung cancer (imaging).
- chest xray
- CT
- biopsy
- PET (?lymph node involvement)
Diagnostic workup for lung cancer (laboratory investigations).
- FBC (?anaemia, leukocytosis, thrombocytosis)
- Ca (elevated)
- LFTs (?raised ALP)
Techniques that can be used to sample lung cancer pathology specimens.
- sputum sample
- FNA
- bronchoscopy
- mediastinoscopy
- throascopy
- surgical thoracotomy
How is NSCLC staged?
TNM staging:
Tumour size
Nodal involvement
Metastases
How is SCLC staged?
- limited disease: cancer only present in one side of the chest
- extensive disease: cancer is present bilaterally in the chest, pleural effusion or distant metastases
Surgical treatment of NSCLC.
- thoracotomy with lobectomy for curative or palliative treatment
- mediastinal lymph node resection
- lymph node sampling
PFTs prior to surgical lobectomy.
- FEV1 >1.2
- DLCO > 60% predicted
Indicators of good outcome post-surgery.
Role of radiotherapy in NSCLC.
- kills cancer cells by causing DNA damage
- external beam radiation therapy
- brachytherapy
- used alongside chemotherapy
