Carcinogenesis & Lung Cancer Flashcards
Major signs/symptoms of Lung Cancer
- Worsening or chronic cough, SOB,
- anorexia, weight loss
- weakness, fatigue
- hemoptysis
- pain @ thoracic site or metastasized site
- sx of metastatic disease: i.e. to adrenal glands, liver, brain, bone.
- paraneoplastic syndrome
Dx test results in lung cancer
- CXR results:
- nodule, enlarging mass
- persistent/non-resolving infiltrate,
- atelectasis
- mediastinal or hilar adenopathy
- pleural effusion
- patients may present with manifestations of metastatic disease (ex. cachexia, seizures secondary to CNS metastases).
- histologic confirmation on biopsy
- endobronchial or transbronchial biopsy
- transbronchial needle aspiration
Lung cancer epidemiology
- leading cause of cancer death
- 5 year survival = <15%
- majority of cases attributable to smoking
Major environmental risk factors for developing lung cancer
- tobacco use + environmental tobacco smoke
- radon gas
- asbestos
- metals
- industrial
- polycyclic aromatic hydrocarbons
Diseases/other factors associated w/lung cancer risk
- COPD secondary to smoking
- dose-response = more severe (lowest FEV1 ==> highest risk)
- sarcoidosis and pulmonary fibrosis/ILD
- hx of previous lung cancer, head and neck cancer, tobacco-related aerodigestive cancer
- lung cancer in a first degree relative = independent risk factor
Major types of lung cancer
- non-small cell carcinoma (NSCLC)
- squamous cell carcinoma = bronchial epithelium; central
- adenocarcinoma = mucous glands; peripheral
- large cell carcinoma = heterogenous group
- small cell carcinoma = bronchial origin ==> central lesions narrow/obstruct bronchi
Common genetic alterations in NSCLC and targeted therapy
- adenocarcinoma ==> Kras, EGFR (epidermal growth factor receptor), EML4-Alk (fusion protein), Braf
- targeted treatments towards neutralizing the effects of these mutations
Staging lung cancer process
- thorough history and physical
- all pts: electrolye testing, liver fxn tests, CXR
- SCLC staging (more micrometastases early in disease) = limited disease (tumor is ipsilateral hemithorax) ==> extensive disease (tumor extends beyond hemithorax)
- NSCLC staged using TNM (Tumor size, Nodal involvement, Metastases)
SCLC treatment
- chemotherapy = cisplatin & etoposide
- radiation ==> tx symptomatic metastases
- not treated surgically
- targeted agents under development
NSCLC treatment
- surgical resection ==> candidates thoroughly assessed based on tumor invasion and lymph node; many inoperable
- staged/assessed via CT and PET scans
- assesed w/PFTs tod etermine severity of any accompanying chronic lung disease
- neoadjuvant therapy = chemo/radiation prior to surgery
- adjuvant chemotherapy = chemo after radiation or surgery
- targeted agents (adenocarcinoma)
Screening for lung cancer
- screening not currently recommended
- screening studies showed some early detection/survival improvements but no overall lung cancer mortaility improvement
- high-risk cohorts may become effective screening population
- tobacco exposure, FHx, etc.
- possible: low-dose, helical CT
Prevention of lung cancer
- smoking cessation
*
Solitary pulmonary nodule (SPN) definition
- < 3cm in size
- surrounded by normal lung
- not associated w/atelectasis or adenopathy
- relatively common finding on CXR
Benign causes of solitary pulmonary nodules
Infectious granulomas
Viral infections: measles, CMV
Round pneumonia
Lung abscess
Pulmonary infarct
Sarcoidosis
Pseudotumors (collections of fluid in the lung fissures)
Malignant causes of solitary pulmonary nodules
Bronchogenic carcinoma
Bronchial carcinoid tumors
Other primary lung tumors – carcinosarcoma, lymphoma, hemangioendothelioma
Metastatic tumors – most commonly colorectal, breast, renal cell, testicular, malignant melanoma, sarcoma
