Chapter 26-lung cancer

Question 0

Types of lung cancers

Answer 0

• primary lung cancers arise from cells that line the bronchi within the lungs and are called bronchogenic carcinomas
• arise from mutated epithelial stem cells
• 2 major categories: non-small cell lung carcinoma (accounts for 75-85% of lung cancer) & neuroendocrine tumors of the lung

Question 1

Lung cancer

Answer 1

• arise from the epithelium of the respiratory tract
• includes other pulmonary tumors, sarcomas, lymphomas, blastomas, hematomas, and mesotheliomas
• most common cause of cancer death in the US, responsible for 31% of all cancer deaths in men, 26% in women, overall 5-year survival remains low at 20%
• most common cause is tobacco smoking, smokers with obstructive lung disease are at greater risk
• other risk factors are second-hand smoking, occupational exposures to certain workplace toxins, radiations, and air pollution
• genetic risk factors include polymorphisms of the genes responsible for growth factor receptors, DNA repair, and detoxification of inhaled smoke

Question 2

Non-small lung cancer: squamous cell carcinoma

Answer 2

• accounts for 30% of bronchogenic carcinomas
• normally located near the hila and project into the bronchi
• symptoms:non-productive cough, or hemoptypsis (coughing up of blood), pneumonia, atelectasis(collapsing of lung)
• chest-pain is associated with large tumors
• they are fairly well localized and tend not to metastasize until late in the course of the disease
• arises from epithelial tissue

Question 3

Non-small cell lung cancer: Adenocarcinoma (tumor arising from glands)

Answer 3

• attributes to 35-40 % of all bronchogenic carcinomas
• growth rate is moderate
• pulmonary adenocarcinoma develops in a step wise fashion through atypical adenomatos hyperplasia, adenocarcinoma in situ, and minimally invasive adenocarcinoma to invasive carcinoma–> usually smaller than 4cm, more commonly arise in the asymptomatic and discovered by routine chest roentgenogram in the early stages , or the individual may be present w/pleuritic chest pain & SOB from pleural involvement by the tumor
• bronchioloalveolar cell carcinoma–> tumors that arise from terminal bronchioles and alveoli, they are slow growing tumors w/an unpredictable pattern of metastasis through the pulmonary arterial system and mediastinal lymph nodes
• symptoms may be asymptomatic, some with pleuritic chest pain and SOB,
• diagnosis: radiography, fiberoptic bronchoscopy, electron microscopy

Question 4

Non-small cell lung cancer: Large cell carcinomas

Answer 4

• accounts for 10-15% of bronchogenic carcinomas
• this cell type has lost all evidence of differentiation and is sometimes referred to as undifferentiated large cell anaplastic cancer
• the cells are large and contain darkly colored stained nuclei
• tumors arise centrally and can grow to distort the trachea and cause widening of the carina
• growth rate=rapid
• symptoms: chest wall pain, pleural effusion, cough, sputum production, hemoptysis (blood in cough), airway obstruction–> pneumonia,

Question 5

Neuroendocrine: small-cell carcinomas

Answer 5

• accounts for 20%
• very rapid growth rate
• spreads rapidly
• most common type of neuroendocrine lung tumor
• central in origin
• metastasize early and widely, worst prognosis
• arises from neuroendocrine cells that contain neurosecretory granules; small cell carcinoma is associated w/ectopic hormone production—> may be first s/s of the underlying cancer
• produce antidiuertic hormone–>syndrome of inappropriate antidiuretic hormone
• can produce gastrin-releasing peptide and calcitonin
• symptoms: cough, chest pain, dyspnea, hemoptysis, localized wheezing, airway obstruction, s/s of excessive hormone secretion: facial edema, muscular weakness, hypertension, hyperglycemia, increased pigmentation

Question 6

Pathophysiology of lung cancer

Answer 6

• tobacco as more than 30 carcinogens & responsible for causing 80-90 % of lung cancers
• probable inherited genetic predispositions to cancers, results in multiple genetic abnormalities in bronchial cells, including deletions of chromosomes, activation of oncogenes, and inactivation of tumor suppressing genes
• most common genetic abnormality associated w/lung cancer is loss of the tumor suppressing gene
• after lung is initiated by these carcinogen-induced mutations, further tumor development is promoted by growth factors
• repetitive exposure of bronchial mucosa to tobacco smoke–> epithelial cell changes that progress from metaplasia to carcinoma in situ, and invasive carcinoma
• further tumor progression invades surrounding tissues, metastasizes to distant sites (brain, bone marrow, and liver)

Question 7

Evaluation & Treatment of lung cancer

Answer 7

-diagnostic tests: chest x-ray, sputum cytologic studies, chest computed tomography, fiberoptic bronchoscopy, and biopsy
-TNM classification: T denotes the extent of primary tumor, N indicates nodal involvement, M describes the extent of metastasis
-only proven way to reduce risk is quit smoking
-treatment for early stage lung cancer is surgical resection
-non-small cell carcinoma, adjunctaive radiation and microwave ablation
-in advanced stage, comfort measures may be used to relieve obstructive pneumonitis or prevent recurrence of pleural effusion
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Question 8

Clinical manifestations of cancer

Answer 8

• pain in 80% of patients
• most common symptoms is increasing fatigue (check pt baseline before and after
• cachexia: muscle wasting, decreased appetite (will be fairly large tumor for this to happen)
• anemia r/t malnutrition, nutritional issues
• Leukopenia: decreased WBC’s which increases risk of infection
• Thrombocytopenia: decreased platelets (clotting) increasing risk of bleeding

Question 9

Types of cancers: Lymphomas

Answer 9

• cancer of lymphatic tissue

- ex: non-hodgkins lymphoma

Question 10

Types of cancers: Leukemias

Answer 10

-Cancers of blood forming cells