18 - Lung Neoplasms Flashcards
What are the three most common tumors of the lung?
Bronchogenic carcinoma (90-90%) - originates in the bronchiel (or bronchialoar) epithelium
Carcinoids (5%)
Other tumors (2-5%)
What lung cancer is the most frequent fatal malignancy in men and women and the most common cancer in the world? Is it more common in men or women?
Bronchogenic carcinoma.
More common in males, but incidence is decreasing in men and increasing in women.
At what time in life do people typically get bronchogenic carcionma?
It’s a disease of middle and late adult life, with a peak incidence in the 50s or 60s.
<2% below age 40.
What are some causes of bronchogenic carcinoma (there’s 5)?
- Tobacco smoking
- Industrial hazards
- Air pollution
- Molerular genetics
- Scarring
What is the association between bronchogenic carcinoma and tobacco smoking? How is this quantified in terms of the effect of smoking on an individual?
There’s a known association between the frequency of lung cancer and the amount of daily smoking.
- smokers are at a 10-fold greater risk
- heavy smokers at a 20-fold risk
- no smoking for 10 years reduces risk to control level
Pack year: Multiply the # of packs of cigarettes smoked per day by the number of years. (ie 10 pack years is smoking 1 pack a day for 10 years or ten packs a day for 1 year).
What is the pathological change caused by tobacco smoking? What are some of the potential carcinogens found in tobacco?
96.7% of smokers have atypical changes in the bronchial epithelium.
Potential carcinogens:
- initiators like benzopyrene
- promoters liek phenol derivatives
- radioactive elements (C14 and K40)
- contaminents like arsenic, nickel, molds, and additives
What are some industrial hazards that can cause bronchogenic carcinoma?
- Radiation
- Uranium miners
-
Asbestos (much higher risk than general pop of getting lung cancer)
- asbestos alone = 5x cancer risk
- asbestos + smoking = 50-90x risk of cancer than general pop
- Latent period of 10-30 yrs
- Other: nickel, chromates, coal, mustard gas, arsenic, beryllium, iron.
What environmental factor may be the cause of lung cancer in a non-smoker?
Air pollution, specifically radon exposure. Radon is a radioactive gas.
Miners are exposed to this at higher concentrations, but it can also occur in high levels inside homes (particularly basements).
What oncogenes may be implicated in bronchogenic carcinoma? What does each case?
Oncogenes:
- c-myx: small cell carcinoma
- k-ras: adenocarcinoma
- EGFR: adenocarcinoma
- EML4-ALK: adenocarcinoma
What tumor supressor genes may be implicated in bronchogenic carcinoma?
P53, RB, p16
Where does benzopyrene exert it’s damage? Wht suggests genetic predisposition to smoking?
Benzopyrene causes DNA damage at the same codons of the p53 gene, as seen in mutations of clinical lung cancers.
Familial clustering and variable risk among heavy smokers suggests genetic predisposition.
How can scarring cause bronchogenic carcinoma?
In most cases, the scar is a response to the tumor.
Sometimes, scar preceds cancer (old infarct, wounds, granulomatous infections).
“Scar cancers” are cancers occuring in the vicinity of pulmonary scares and are usually adenocarcinomas.
What are clinical features of bronchogenic carcinoma? How long is the average duration of symptoms?
Pts usually present in their 50’s with: cough (75%), weight less (40%), chest pain (40%), and dyspnea (20%).
Avg duration of symptoms is 7 months.
May be diagnosed upon secondary sprea.
What is a pancoast tumor?
Tumor at the extreme apex of the lung.
Involvement of the superior cervical sympathetic ganglion is seen and causes horners syndrome:
- ipsi lid lag
- miosis
- ipsi anhydrosis
What cells are seen in small cell cardinoma?
Oat cell: lymphocyte-like
Intermediate cell: (polygonal)
Compbined: usually with squamous
What are three different types of non small cell carcinoma?
Squamous cell carcinoma.
Adenocarcinoma:
- glandular
- papillary
- solid
- (lepidic) bronchioalveolar
Adenosquamous carcinoma
What are four different types of large cell carcinomas?
- Neuroendocrine
- Undifferentiated
- Giant cell
- Clear cell
What is the classification of bronchogenic carcinoma?
It’s either small cell carcinoma or non-small cell carcinoma.
Small cell is sensitive to chemo and radiation but not to surgery because it’s infiltrative nad difficult to ressect.
Non-small cell carcinoma can often be treated with surgery.
What are some newly emphasized aspects of bronchognic carcinoma classification?
Recent advances in thoracic oncology are leading to a shift in emphasis on accurate subtyping.
Subtyping allows for more precise treatment plans.
(Attached is the slide, but he didn’t discuss each of these in detail so I’m thinking we don’t need to know the details).
What are characteristics of squamous cell carcinoma? Is it more common in men or women?
Most common type in males.
Caused by cigarettes smoking.
Cenctral cavitary necrosis and usually arises centrally (main or lobar bronchi); usually endobronchial, polypoid growth
What is the histology seen in squamous cell carcinoma?
- Keratin formation
- Intercellular bridges
- Cellular atypia
- Invasion
- Well/moderately/poorly differentiated subtypes depending on degree of squamous differentiation
What is the most common form of lung carcinoma in the US? Does it effect men or women more?
Adenocarcinoma (25-40%)
Most common type in women and non-smokers (although most with it are smokers)
Describe the appearance of adenocarcinoma?
Usually peripheral with pleural retraction or puckering. Associated with scarring.
Grows more slowly and metastasizes more freqeuntly than squamous cell carcinoma.
Asymptomatic with a lake diagnosis.
What is an adenocarcinoma? What are the histologic patterns?
Malignant epithelial tumor with glandular differentiation or mucin production.
Histologic patterns:
- Glandular (acinar) with mucin
- Papillary
- Solid
- (Lepidic) Bronchioalveolar
