The Role of Vitamin D in Preventing Lung Cancer
Lung cancer is the most common deadly cancer among both men and women. Studies suggest that normal vitamin D levels may help prevent lung cancer. In the United States in 2009, about 220,000 new cases of lung cancer were diagnosed. That same year, about 153,000 people died of lung cancer. People over age 65 are mostly affected.
It’s no secret that long-term exposure to smoke from cigarettes causes lung cancer. Of the 15 percent of lung cancer patients who haven’t been exposed to smoke, other factors, like exposure to radon gas, asbestos, and air pollution, are responsible.
Lung cancer signs and symptoms
Lung cancer is classified according to the type of cell involved. Two major types make up 97 percent of all lung cancers. Most lung cancers (80 percent) are non-small-cell lung cancers. The other 17 percent are small-cell lung cancers, which, despite being made up of small cells, produce a large tumor.
The small-cell cancers contain hormones that can cause abnormalities like high calcium from production of a hormone that mimics parathyroid hormone. Another hormone produced by small-cell cancers is antidiuretic hormone that results in low blood sodium and fluid overload.
Lung cancer has the following signs and symptoms:
Cough that produces blood
Pain in the chest or abdomen
Shortness of breath
Spread to the brain, bones, liver, and kidney
Weight loss and loss of appetite
Lung cancer diagnosis and treatment
A chest X-ray is the first study done to look for lung cancer. It may show the tumor and/or widening of the structures in the middle of the chest from the cancer’s spread to the lymph nodes there. The tumor then is biopsied to make a definitive diagnosis.
Treatment depends on the type of cell, the amount of spread, and the physical fitness of the patient. The treatments include surgical removal (if possible), chemotherapy, and radiation therapy. Surgery can involve anything from removing part of the lobe of the lung in which the tumor is found, to removing an entire lung. As with other cancers, the tumor is staged based on how much spread has occurred at the time of diagnosis.
Prognosis for either type of lung cancer is poor. By the time the diagnosis is made, the cancer is usually advanced. It makes good sense to try to prevent lung cancer instead of treating it after it has occurred.
The single best lung cancer prevention advice is to reduce or stop smoking. Smoking has been reduced in the United States and throughout the world by laws prohibiting smoking in public places. If a person stops smoking before age 45, he is at low risk of developing cancer.
Vitamin D’s role in lung cancer
Several discoveries seem to point to a relationship between normal levels of vitamin D and the prevention of lung cancer. Some of the more significant findings include the following:
Normal lung tissue, premalignant lung tissue, and malignant lung tissue all have the vitamin D receptor. For calcitriol to perform its anti-cancer work, it has to be able to bind to the appropriate tissue.
There is an inverse association between the amount of exposure to ultraviolet B rays (the rays of sun that are responsible for triggering vitamin D production in your body) and the occurrence of lung cancer. The more exposure, the less common the cancer.
Patients who have surgery for lung cancer during the summer, when ultraviolet B is at its height, have a better prognosis than those who have surgery in the winter.
What is missing to complete this story are studies that show that lung cells or lung cancer cells are influenced by calcitriol; that high serum levels of 25-hydroxyvitamin D are associated with low lung cancer risk; and that giving vitamin D supplements to people with low vitamin D status help them avoid lung cancer.