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 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
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
What is bronchioalveolar carcinoma? What does it look like grossly?
A subset of adenocarcinoma; 1-9% of all lung carcinomas.
Gross: single peripheral nodule, multiple nodules, or diffuse pneumonia-like infiltrate
What is the histology seen with bronchioalveolar carcinoma?
Lepidic spread (tumor cells spread along alveolar spaces)
- nonmucinous (clara cells, type 2 pneumotyes) in 2/3 cases
- Mucinous (tall columnar mucinous cells) - worse prognosis
What is the gross appearance of small cell carcinoma? What can they produce?
Extensive necrosis, crush artifact.
Secretory granules of neuroendocrine type.
Ectopic hormone production (paraneoplastic syndrome)
Responds to chemoradiation.
What does small cell carcinoma look like on histology?
Tightly packed without a lot of cytoplasm (actual cells themselves are not small)
Mimics lymphoma.
Other than small cell cancer, what are two other bronchogenic carcinomas of the lung?
Large cell carcinoma, undifferentiated: 6% 5-year survival.
Giant cell carcinoma: highly malignant, most peripheral, <10 mo survival.
What is adenosquamous carcinoma? Where in the lung does it occur?
Evidence of squamous cell carcinoma and adenocarcinoma in the same neoplasm.
Peripheral tumor associated with scar.
Majority of pts are smokers.
What are some (6) examples of paraneoplastic syndromes? What cancer is each associated with?
What are carcinoid tumors? How aggressive is this tumor?
Low-grade malignant neoplasm of neuroendocrine differentiation.
Most pts are <40 and 20-40% are non-smokers.
Fairly indolent and tend to be central and well-circumscribed.
What does carcinoid tumor look like on histology? What does immunohistochemistry show?
Nests, cords, masses. Uniform cells with round nuclei.
“salt and pepper” chromatin (dispersed chromatin)
Immunohistochemistry shows:
- NSE+
- Chromogranin+
- Synpatophysin+
(^sorry I don’t know what those mean but I also don’t think they are important)
