Lung Tumors Flashcards
1
Q
What are different types of lung tumors?
A
-
Brochogenic Carcinoma – 90 – 95%
- Originate in the bronchial (or bronchiolar ) epithelium
- Carcinoids – 5%
- Other tumors – 2- 5%
2
Q
Describe the incidence of bronchogenic carcinomas:
A
- Public enemy # 1 in industrialized countries
- Incidence is decreasing in men and increasing in women
- Most frequent fatal malignancy in men and women
-
Most common visceral malignancy in males
- 1/3 of cancer deaths in males/ 7% of cancer deaths in both sexes
- Males > Females
-
Dramatic increase in incidence in women (cigarette smoking)
- Lung Ca has surpassed breast Ca as a cause of cancer death in women
- A disease of middle and late adult life, with a peak incidence in 50s or 60s
- < 2% below age 40
3
Q
What are the etiologies of bronchogenic carcinomas?
A
- Tobacco smoking
- Industrial hazards
- Air pollution
- Molecular genetics
- Scarring
4
Q
What is the statistical evidence for tobacco smoking as a cause of bronchogenic carcinoma?
A
-
Association between frequency of lung ca. & amount of daily smoking
- Smokers 10-fold greater risk
- Heavy smokers 20-fold greater risk
- X smoking for 10 yrs, reduces risk to control level
- Tendency to inhale
-
Duration of smoking habit
- Pack year - calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked
- Other associations – lip, tongue, mouth, pharynx, larynx, esophagus, UB, pancreas, kidney
5
Q
What is the clinical evidence for tobacco smoking as a cause of bronchogenic carcinoma?
A
-
Histologic changes in the respiratory tract of smokers
- 96.7% smokers - atypical changes in bronchial epithelium
- 0.9% control subjects - similar changes
6
Q
What is the experimental evidence for tobacco smoking as a cause of bronchogenic carcinoma?
A
- Cancer induction in experimental animals by exposure to tobacco smoke
-
Potential carcinogens –
- Initiators (benzopyrene)
- Promoters (phenol derivatives)
- Radioactive elements (carbon-14, potassium-40)
- Contaminants (arsenic, nickel, molds, additives)
- Experimental mice – Skin tumors, few lung cancers (bronchioloalveolar carcinoma)
7
Q
What industrial hazards potentially lead to bronchogenic carcinoma?
A
- Radiation – Increased incidence in Hiroshima/Nagasaki survivors
- Uranium miners – lung cancer rates higher than general population
- Asbestos – Much higher risk than general population of developing lung cancer
- Other hazards – Nickel, chromates, coal, mustard gas, arsenic, beryllium, iron
8
Q
Why are people exposed to asbestos at a higher risk of developin bronchogenic carcinoma?
A
- Asbestos w/o smoking ⇒ 5 times greater risk than gen. pop.
- Asbestos + smoking ⇒ 50 – 90 times greater risk than gen. pop.
- Latent period ⇒ 10 – 30 years
- 1/5 deaths – Lung Ca.
- 1/10 deaths – Mesothelioma
- 1/10 deaths – GI Ca
9
Q
- How can air pollution increase the risk of bronchogenic carcinoma?
- Who is partciularly at risk?
A
- Indoor air pollution – Radon exposure
- ubiquitous radioactive gas
- lung cancer in non-smokers may be attributed to radon exposure
- Miners exposed to higher concentrations
10
Q
What are the genes/proteins potentially involved in bronchogenic carcinoma?
A
- Genetic alterations which accumulate and ultimately lead to neoplasia
-
Oncogenes
- C-myc ⇒ small cell carcinoma
- K-ras, EGFR, EML4-ALK ⇒ adenocarcinoma
-
Tumor suppressor genes
- p53
- Retinoblastoma
- ? Genes on short arm of Chromosome 3
11
Q
__________ causes DNA damage at the same codons of the p53 gene
A
Benzopyrene causes DNA damage at the same codons of the p53 gene
- Familial clustering and variable risk among heavy smokers suggest genetic predisposition
12
Q
- What is the role of scarring in brochogenic carcinoma?
- Which type is scarring usually seen?
A
-
“Scar cancers” – Cancers occurring in the vicinity of pulmonary scars
- Usually adenocarcinomas
- In most cases, the scar is a response to the tumor
- Sometimes, scar precedes cancer (old infarcts, wounds, granulomatous infections)
13
Q
**Bronchogenic Carcinoma: **
Clinical Features and Course
A
- Usually present in their 50s
- Average duration of symptoms ⇒ 7 months
-
Major presenting complaints:
- cough (75%)
- wt loss (40%)
- chest pain (40%)
- dyspnea (20%)
- Increased sputum production – Cytology
- May be diagnosed upon secondary spread
14
Q
What is a Pancoast tumor? What can it lead to?
A
- Tumor at the extreme apex of the lung
- Involvement of superior cervical sympathetic ganglion
-
Horner’s syndrome:
- Ipsilateral lid lag
- Miosis
- Ipsilateral anhydrosis
-
Horner’s syndrome:
15
Q
What are the two major classifications of bronchogenic carcinomas?
A
- Small cell carcinoma
- Non-small cell carcinoma
20
Q
Squamous cell carcinoma:
- Incidence:
- Clinical presentation:
- Histology:
A
- The most common type in Males
- Cigarette smoker
- Central cavitary necrosis
- Usually arise centrally (main or lobar bronchi)
- Usually endobronchial, polypoid growth
-
Histology:
- keratin formation, intercellular bridges, atypia and invasion
- Well/moderately/poorly differentiated subtypes depending on degree of squamous differentiation
21
Q
Adenocarcinoma:
- Incidence:
- Clinical presentation:
A
- Most common type in women and non-smokers (most patients with adenocarcinoma are smokers)
- Most common form of lung carcinoma in USA
- Usually peripheral with pleural retraction or puckering
- Associated with scarring
- Grow more slowly, metastasize more frequently than squamous cell carcinoma
- Asymptomatic (peripheral tumor) – Late diagnosis
22
Q
Bronchioloalveolar carcinoma:
- Incidence:
- Clinical presentation:
- What has a worse prognosis?
- Histology:
A
- A subset of adenocarcinoma
- 1% – 9% of all lung carcinomas
-
Gross
- Single peripheral nodule
-
Multiple nodules (several lobes/bilateral) –
- multifocal/aerogenous spread
- Diffuse pneumonia-like infiltrate
-
Histology — Lepidic spread (tumor cells spread along alveolar septa)
- Nonmucinous (Clara cells, type 2 pneumocytes) – 2/3 cases
- Mucinous (tall columnar mucinous cells) – Worse prognosis
25
Q
Large cell carcinoma
- Incidence:
- Clinical presentation:
- Prognosis:
A
- 10 – 15% of lung cancers
- Pleomorphic, large cells without differentiation
- Ultrastructural evidence of glandular or squamous differentiation
- 5-year survival 6%
-
Giant cell carcinoma
- Highly malignant
- Mostly peripheral
- < 10 month survival
26
Q
Adenosquamous carcinoma
- Incidence:
- Clinical presentation:
A
- 1 – 3% of lung carcinomas
- Definite evidence of squamous cell carcinoma and adenocarcinoma in the same neoplasm
- Peripheral tumor, associated with scar
- Clinical presentation and behavior similar to adenocarcinoma
- The majority of patients are smokers
33
Q
What can be seen microscopically in carcinoid tumors?
A
- Nests/ cords/ masses
- Uniform cells with round nuclei
- “Salt & Pepper” chromatin
- IHC: NSE, chromogranin, synaptophysin +
