I quit smoking a month ago and I'm coughing up blood, do I have lung cancer?

It is not uncommon for smokers to have an increase in coughing for several weeks after they quit. Smoking inhibits the work of the cilia in the lungs whose job it is to "sweep out" debris that in inhaled. They are damaged and/or paralyzed from the tar and other harmful chemicals in tobacco smoke. Once you quit, they work over time to rid your lungs of the accumulation of the gunk in your lungs. What you cough up can be a variety of colors, including mucus that is red-tinged but is not actually blood.

I would suggest that you speak with your doctor. Coughing up actual blood (not just red-looking mucus) and unexplained weight loss can be signs of lung cancer. Your doctor may order tests to see what is going on.

One test your doctor may order is a low-dose CT scan. While in your case it would be ordered as a diagnostic test, it can also be ordered for smokers with no symptoms of lung cancer as a screening test. The Centers for Medicare and Medicaid just approved  this test as a covered screening test in February, 2015. If you meet the following criteria, you doctor can discuss the risks and benefits of having this done:

• No symptoms of lung cancer 
• Be between the ages of 55 and 77
• Be a current smoker or have quit within the last 15 years
• Be a "30 - pack smoker":

one pack a day = a 1 pack year. 1 pack a day x 30 = 30 pack smoker

2 packs a day x 15 years = 30 pack smoker

1/2 pack per day x 60 years = 30 pack smoker

For more information on low-dose CT scans click here. These are the guidelines for Medicare and Medicaid but not all health insurance polices will cover this, however there may be resources in your area. Contact the office of your local American Cancer Society or American Lung Association who may have a list of local resources for you. 

Link Between Lung Cancer and Smoking

For years the tobacco companies said that smoking did not cause lung cancer. We now know that smokers are at a much higher risk of developing lung cancer and about 10% of all smokers will develop the disease. About 90% of all lung cancers are in smokers. This article tells of several genetic studies that are showing certain genetic traits that may make a person more likely to become addicted to smoking and also more likely to develop lung cancer. So reality might be that lung cancer is a relationship between heredity and environment. Lung cancer has been so fatal because it is usually found late after it has already spread but a new type of CAT scan, a spiral CAT Scan can find tumors that are small enough to be treatable. This test is not covered by insurance because it hasn't been proved that the survival rate of finding a lung cancer tumor when it is smaller increases life expectancy but it only makes sense to find it as early as you can.

http://www.medscape.com/viewarticle/576699?src=mp&spon=17&uac=103794FK