Lung Cancer: Background information when reading When Breath Becomes Air

Lung Cancer

This article relates to When Breath Becomes Air

The late Paul Kalanithi, a non-smoking neurosurgeon, was diagnosed with squamous cell lung cancer. When Breath Becomes Air is his autobiography.

"Cancer" is a name given to a collection of diseases in which a set of cells in the body begin dividing abnormally and without stopping. Unlike their healthy counterparts, cancer cells lack the mechanism that tells them to stop multiplying, as well as the process known as programmed cell death (aka "apoptosis"), which gets rid of unneeded cells. These damaged cells eventually crowd out the good and may lead to death if the condition can't be treated.

Lung cancer is the second most common cancer in men (following prostate cancer) and women (after breast cancer). About 221,200 new cases of lung cancer were diagnosed in 2015 (13% of all new cancers), and an estimated 158,040 died from the disease in that same year. Each year, more people die from lung cancer than from colon, prostate and breast cancer combined.

There are several types of lung cancers:

• Small Cell Lung Cancer (SCLC) makes up just 10-15% of lung cancer cases. Also called oat cell cancer, this fast-spreading form of the disease is rare in people who haven't smoked.
• Non-Small Cell Lung Cancer (NSCLC), which is the most common form of lung cancer, making up approximately 85% of cases. This is further divided into three subtypes:
  • Often associated with smoking, squamous cell carcinoma starts in the squamous cells – flat cells that line the inside of the airways of the lungs. It makes up 25-30% of lung cancers. Kalanithi had this kind of cancer even though he was a non-smoker.
  • Adenocarcinoma is diagnosed in 40% of lung cancer patients. This form of cancer starts in the cells that normally produce mucus. It is the most likely lung cancer to impact non-smokers and other populations that aren't normally associated with lung cancer, such as young people; it is also more common in women than men. Adenocarcinoma is a slow-growing cancer and the prognosis for those with this form of the disease is considerably better than the other forms of NSCLC.
  • Large cell carcinoma is fast-growing and difficult to treat, and impacts 10-15% of those with lung cancer.
• Lung Carcinoid Tumors, also known as neuroendocrine tumors, are groups of lung cells that have formed a mass that can be removed via surgery. Less than five percent of lung cancers fit this category; it is slow-growing and contained, and consequently the survival rate is quite good.

Lung cancers are very difficult to diagnose which is why they are often life-threatening. In its early stages abnormality can only be detected by examining cells under a microscope, and at this point diagnostic methods like CT scans show nothing. Symptoms such as feeling tired or weak, coughing, shortness of breath or hoarseness don't appear until later in the disease, and because they can be caused by more common maladies the root cause is often overlooked. In addition, lung cancer metastasizes – spreads – to the lymph nodes easily, which in turn transmit the cells to other organs.

It's estimated that 80% of lung cancers are the result of smoking or repeated exposure to second-hand smoke. Other causes include a genetic predisposition to the disease as well as environmental exposure to carcinogenic substances such as asbestos, diesel exhaust and radon.

Depending on the type and how advanced it is, doctors use various methods to treat lung cancer:

• Surgery, where part of the lung is removed (anything from a small chunk of tissue to the entire organ)
• Chemotherapy, which uses intravenous or orally administered drugs to kill cancer cells. This form of treatment is often used after surgery to clean up any remaining cells the resection may have missed.
• Radiation therapy, in which high-powered energy beams that kill cancerous cells are directed at the lungs from outside the body.

The newest weapon in the physician's arsenal is targeted drug therapy. Pharmaceuticals have been developed that target certain types of cancer cells based on the genetic profile of the cell in question. New drugs of this type are being developed and tested constantly, but they're expensive and their efficacy has sometimes been called into question.

Filed under Medicine, Science and Tech

This "beyond the book article" relates to When Breath Becomes Air. It originally ran in February 2016 and has been updated for the January 2016 edition. Go to magazine.

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