Lung Tumors-Prager Flashcards
What portion of lung cancers occur in smokers?
80-90%, 60x risk for 40 pack years compared to nonsmokers
What are molecular genetic markers for lung cancer
– 3p deletion, one of the most consistent chromosomal
abnormalities in lung cancer: loss of the short arm of
chromosome 3
– Mutation of oncogenes (K-ras, Endothelial growth
factor receptor-pill blocks effects)
– Deletion and/or mutation in tumor suppressor genes
(p53)
– Telomerase activity increase (restores length of
chromosome—immortal cells
What are the classifications of lung tumors/malignant epithelial tumors?
Carcinoids/atypical carcinoids, small cell carcinoma (18%), nonsmall cell carcinoma: large cell CA (9%), squamous CA (30%), adenocarcinoma (31%): bronchioloalveolar, various subtypes.
Adenocarcinoma in lungs
• Most common type of carcinoma in nonsmokers and in women
• More often peripheral than central
• Small tumors can be associated with nodal
and distant metastases
• Must distinguish primary from metastatic
Bronchioloalveolar cell carcinoma (BAC)
Adenocarcinoma in-situ
• Mucous-secreting or non-mucinous
adenocarcinomas that line alveolar spaces
• Often multicentric making resectional cure
unlikely or impossible (can excise 1 but not 4 tumors)
• May be indolent with slow progression over years (can live with for years without death)
• Infrequently metastasizes outside chest
• May be confused with pneumonia on chest x ray
Squamous cell carcinoma in the lung
• Often bulky, large tumors of bronchogenic
origin, that invade adjacent structures; faster
doubling time than adenocarcinoma
• Usually arise in mainstem or lobar bronchi,
often visualized bronchoscopically
• Metastasis in relation to tumor size may
occur later than adenocarcinoma
• May cavitate due to central necrosis
Large cell carcinoma in lungs
No differentiation twoards squamous or adenocarcinoma
Aggressive, poor prognosis
If US exam, many show glandular or squamous differentiation
Separated out because high grade and poor prognosis
Small Cell Carcinoma in the lung
• Increasing in frequency (25% of lung Ca)
• 99% occur in smokers
• Usually centrally located and disseminated
at time of diagnosis; surgery not an option
• May be very responsive to chemotherapy
with 15-20% cure in limited disease—but
only a fraction of patients present that way
• May secrete biologically active peptides
Which lung cancers are centrally located and which are peripheral?
Central: Squamous cell, small cell carcinoma, carcinoid
Peripheral: adenocarcinoma
Clinical Presentation of Lung Cancers
• Endobronchial tumor: persistent cough;
hemoptysis; fixed wheeze (if in mainstem bronchus) or stridor; postobstructive pneumonia; weight loss
• Peripheral tumor: often asymptomatic until local
invasion or metastases cause symptoms
• Chest pain; dyspnea; brain metastases (seizures,
neurologic deficits); bone mets (pain, pathologic
fractures, hypercalcemia)
• Hoarseness from left vocal cord paralysis
from damage to L recurrent laryngeal nerve
• Superior vena cava syndrome- face swells from lack of venous return
• Obstructed bronchus causing cough,
wheeze, pneumonia, atelectasis, bleeding
Dyspnea
Where are the most common sites for lung cancer metastasis?
brain (CVA, seizure);
bone (pain, pathologic fracture, spinal cord
compression); liver (pain, jaundice);
adrenal glands
What are the considerations for screening with CXR or CT scan?
CXR is not sensitive enough and CT scans are too sensitive, with too many false positives.
Methods of tissue diagnosis of lung cancer
– Flexible bronchoscopy (endobronchial tumor)
– Transthoracic CT-guided needle biopsy (peripheral
lesions)
– Thoracentesis
– Open lung biopsy (Video-assisted thoracoscopy)-like laproscopy
– Peripheral node, mass; liver biopsy; brain biopsy
– Sputum cytology
What are the criteria for staging of lung cancer
• T—tumor size, location, invasion
• N—nodal involvement
• M—metastases within and outside the
thorax
T1-T4 in cm
N0-N3 from no nodes to contralateral or mediastinal or supraclavicular nodes
M0 or M1 for metastases
Survival based on staging
Best prognosis: Stage IA (T1, N0, M0): 75% 5 year survival
Worst prognosis: Stage IV (M1): <20% survival after even 1 year
How is lymph node staging done?
• CT scan
• Positron Emission Tomography (PET) scan
more sensitive and specific than CT—very
expensive (moreradionucleated glucose means more malignant reactivity)
• Flexible bronchoscopy—Transbronchial
needle aspiration-guided by ultrasound
• Mediastinoscopy—most sensitive and
specific for mediastinal node (U shaped incision at suprasternal notch)
What imaging tests are done for staging?
CT, PET, MRI to rule out brain metastasis.
Treatment of NSCLC
• Stage I, II: Resection—lobe(s), or entire
lung; adjuvant chemotherapy for IB or more
• Stage IIIa: neoadjuvant
chemotherapy (try to convert inoperable situatino into operable) + radiation, and if excellent
tumor response, follow with surgery
• Stage IIIb: chemotherapy +/- radiation
• Stage IV: chemotherapy
What is the treatment of small cell lung cancer?
Never surgery
- Limited: chemotherapy + radiation (prevent spreading)
- Extensive: chemotherapy
Treat effects of tumor (gene effects by tumor markers: ex: EGFR with tyrosine kinase inhibitors)
Malignant Pleural Effusion
• Common, difficult to treat complication of
primary and metastatic lung cancer
• Symptoms: dyspnea, chest pain
• Treatment: Thoracentesis for diagnosis; for
defintive treatment chest tube or VATS with
pleurodesis
– talcum powder-saline suspension in pleural space to
cause pleural inflammation and scarring leading to
adhesion of pleural surfaces
– Occasional chemotherapy into pleural spac
Malignant Mesothelioma
• Malignant tumor of pleural mesothelium
• High association with prior asbestos exposure—
even if decades before
• Usually fatal—infrequent cures require radical
resection of entire lung and pleura followed by
chemoRx
• Improving efficacy of palliative chemoRx
• Often presents with pain and/or pleural effusion
• May involve abdominal mesothelium
Bronchial Carcinoid
• Malignant neoplasm of neuroendocrine cell origin
• Can be central or peripheral; when endobronchial may
present with hemoptysis or post obstructive pneumonia
• Tumor of low grade malignancy—if unresected may take
years to metastasize to regional nodes or extrathoracic sites
• 1-5% of all lung tumors—unrelated to smoking
• Composed of uniform small cells; EM shows
neurosecretory granules
• Excellent prognosis if resected
Evaluation of Solitary Pulmonary
Nodule
• Common clinical problem: benign or malignant?
• Benign etiology suggested by
– Small nodule (<1cm), smooth margin
– Young patient
– Non-smoker
• Old chest films critically important
• Evaluate with chest CT +/- PET; occasional need
for biopsy (bronchoscopy, needle asptn.), surgery
• Often can be followed with repeat imaging studies
to check for growth
