B2.062 Lung Cancer Flashcards
when is the peak incidence for lung cancer?
40-70 years
what are the 3 primary types of bronchogenic carcinoma?
small cell carcinoma (10-15%)
adenocarcinoma (40%)
squamous cell carcinoma (25-30%)
what constitutes a bronchogenic carcinoma?
cancers of epithelial elements of the lung itself
what cells form lung adenocarcinomas?
gland forming epithelium
columnar epithelium in respiratory tract/lungs
what cells form lung squamous cell carcinomas?
squamous epithelium
normally no squamous cells in the respiratory tract
arise from pathologic metaplasia bc squamous are more resilient
what factors other than smoking could induce patches of squamous cell metaplasia?
harsh environmental exposures
what % of lung cancers occur in smokers?
80%
what % of heavy smokers get lung cancers?
11%
how do cytochrome p-450 polymorphisms relate to lung cancer?
cytochrome p-450 is responsible for the metabolism of procarcinogens into carcinogens
how do DNA repair gene mutations affect lung cancer?
toxic damage more likely to cause cancer in cells with mutated repair mechanisms
what is the latent period of asbestos?
> > 10 years
very long
what is the most common malignancy associated with asbestos exposure?
lung cancer
FAR more common than mesothelioma, mesothelioma just easier to prove a direct correlation (lawsuits)
how is asbestos exposure affected by smoking?
incidence of lung cancer due to asbestos exposure is increased 10 fold when coupled with smoking
what oncogenes are linked to lung cancer?
receptor tyrosine kinases (EGFR, ALK, ROS, MET, RET)
KRAS (G protein)
MYC (transcription factor)
what is the goal of lung cancer screening?
detect small cancers
too hard to detect abnormalities before they occur
what methods can be used to screen high risk individuals?
CT
what are some clinical features of lung cancer?
cough
weight loss
chest pain
dyspnea
what are 3 general effects of local invasion and their reason for arising?
hemoptysis- destruction of blood vessels in lungs
pneumonia- tumor can obstruct and cause poor perfusion in a portion of the lung
pleural effusion- inflammatory mediators or tumor can move into pleural space
what is horner syndrome?
invasion of cervical sympathetic nerve plexus by apical tumors
pain in ulnar nerve, ptosis, miosis (pupillary constriction), anhidrosis (inability to sweat) on same side as lesion
what is superior vena cava syndrome?
pressure on SVC causing obstruction
facial edema, distention of neck veins, compressive symptoms
what are common symptoms of lung cancer metastasis?
bone pain
headache
seizures
other CNS findings
what are common sites of lung cancer metastasis?
lymph nodes, liver, adrenal gland, bone, brain
what is the etiology behind paraneoplastic syndrome?
inappropriate secretion of hormone or hormone like substance by tumor cells
autoantibodies
what are some examples of paraneoplastic syndromes associated w lung cancers?
cushing syndrome- ACTH (small cell carcinoma)
syndrome of inappropriate ADH secretion- ADH (small cell carcinoma)
hypercalcemia- PTH, PTH-RP (squamous cell carcinoma)
myasthenia gravis/ Lambert-Eaton syndrome- autoantibodies
clubbing- hypertrophic pulmonary osteoarthropathy
characterize adenocarcinoma lung cancers
most common subtype, especially in women peripheral location (smaller airways) acinar, papillary, lepidic types most common lung cancer in never smokers
what are common characteristic in lung cancer of never smokers?
most adenocarcinomas
more common in women
most have EGFR or other receptor tyrosine kinase mutations
NOT typically KRAS mutations
more responsive to targeted molecular therapy
why should you test for KRAS mutations in adenocarcinomas?
if you want to treat with a tyrosine kinase inhibitor, this WILL NOT work if there is also a KRAS mutation downstream in the signaling pathway
why is a RAS mutation hard to target in therapy?
common G-protein for many life functions
characterize squamous cell carcinoma lung cancer
highly associated with smoking
more common in males
usually central in location
usually due to deletion of tumor suppressor genes (more resistant to chemo and radiation)
what is a histologic marker of a squamous cell?
keratin production
characterize small cell carcinoma lung cancer
highly associated with smoking most aggressive course frequently metastatic at presentation arise from neuroendocrine cells very poor survival
what is a histologic marker of small cell carcinoma?
high nucleus to cytoplasm ratio
characterize mesothelioma
arise from mesothelium (pleura, other serosal membranes)
strongly associated with asbestos
pleural effusion common
poor prognosis
what is the most common site of metastasis?
the lung!!!!!!!!!
what is the typical pattern of involvement in lung metastasis?
multiple nodules (cannonball lesions)
classify small cell carcinoma
morphology
neuroendocrine differentiation by IHC
classify squamous cell carcinoma
morphology
keratin production
squamous differentiation by IHC
classify adenocarcinoma
morphology
mucin production
glandular differentiation by IHC
