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Thursday, November 18, 2010

Everything you need to know about lung cancer

Today is the Great American Smokeout, so I thought today would be a great day to discuss one disease that might be eradicated some day if we all quit smoking forever.

With pneumonia and COPD being the top two diseases we RTs treat inside the hospital, a close third is lung cancer. So this is yet another good reason to do a quick review of what lung cancer is all about.

Lung cancer is actually the #1 cause of death from cancer, killing as many as 1.4 million people worldwide. And a majority of cases are linked with cigarette smoking. So, like COPD, one could imagine a world with very few cancer cases if nobody smoked.

As you can see by the chaart, lung cancer was basically near zero before the advent of the 20th century, and as the number of people who smoked increased in the 19th century, so to did the rate of lung cancer and lung cancer related morbidity and mortality. It just took lung cancer 10 years to catch up with the rising number of smokers.

Epithelial cells are those cells that line the surface of your body. It lies on top of connective tissue, and many glands are derived from it. It's actually classified as the primary body tissue, with connective tissue, muscle tissue and nervous tissue following.

According to wikipedia, the following are functions of epithelial cells:

  • Secretion
  • Selective absorption
  • Protection
  • Transcllular transport
  • Detection of sensation
  • Specialization (as in the lungs they produce cilia)
Epithelial cells divide, and basically produce clones of themselves. Actually, every seven years your body has produced an effective clone of itself. If an epithelial division produces an error, this is what cancer is.

According to Medical News Today, "Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors." Lung cancer interferes with lung function, and can "release secretions that alter body function."

When a cancer displays limited growth and stays in one spot it's considered malignant, yet most cases of lung cancer are considered to be malignant carcinoma's of the lung.

There are two types of lung cancer, and the treatment depends on the type:

1. Small Cell Carcinoma: This is slightly more common in men than women, although it's the least common type of lung cancer. It was formally referred to as oat cell carcinoma.

It responds to radiation and chemotherapy. According to Google Health, this is the fast growing type of cancer and spreads much faster than non small cell carcinoma. It is the aggressive type of lung cancer, and because they spread so quickly, they usually metastasise to other parts of the body before they are diagnosed, including brain, liver and bone. This is why it is usually not treatable with surgery.

Because it spreads so rapidly, prognosis is generally grim, and is likewise associated with smoking.

2. Non Small Cell Carcinoma: Treated with surgery, and can also be treated with chemotherapy and radiation. According to chemo.net, these are diagnosed by default, when all other possibilities have been absorbed, and include about 10-14% of lung cancers. The best way to diagnose is with biopsy. "They grow rapidly, metastasise fast, and are strongly associated with smoking."

Common causes of lung cancer:
  • Cigarette smoke: Cause of 85% of cases
  • Genetic factors: Cause of most childhood cases
  • Radon gas
  • Asbestos
  • Air polution
Lung cancer will show up on an x-ray and CT, and is then confirmed by a bronchoscopy and lung biopsy. Prognosis will depend on how early the cancer is caught and by how much it has metastasised (spread).

It's interesting to note that the five year prognosis of this disease is only 14%, although this does depend upon the stage of treatment.

Symptoms may include (but are generally nonspecific):
  • Bloody sputum (phlegm) (hemoptysis)
  • Chest pain
  • Bone pain
  • Cough (chronic cough
  • Loss of appetite
  • Shortness of breath (Dyspnea)
  • Weight loss
  • Wheezing
  • Facial swelling
  • Fever
  • Hoarseness or changing voice (Dysphonia)
  • Swallowing difficulty (Dysphagia)
  • Weakness
  • Clubbing of the fingernails (not too common) due to chronic hypoxia (low oxygen to the blood)
  • Catexia: Weight loss, fatigue and loss of appetite

It causes shortness of breath because it can block the air passages in your lungs, and leaves an accumulation of secretions behind the blockage, which predisposes these patients to pneumonia. Since lung cancers have fragile surfaces and a "rich" blood supply, they are prone to producing bloody secretions.

Again, the main cause is smoking, since cigarette smoke has about 60 known carcinogens (things that are likely causes cancer), plus nicotine suppresses the immune response to lung cancers. I list all the hazardous chemicals in cigarette smoke in this post.

Along with smoking, women taking hormones are at increased risk for developing lung cancer. Among all males who smokethere is a 17.2% risk of developing lung cancer at some point in their lifetimes, and among women this rate is 11.6%.

Significant to note, among nonsmokers the risk is only 1.4% and 1.3% respectively. So you can now understand the significance of smoking education to children and smoking cessation programs to those who already smoke.

So today is the Great American Smokeout, and a great day to set aside to educate your family members about the dangers of smoking and the importance of quitting for those who do smoke.

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