Blood in Phlem

I have COPD and am oxygen mostly at night but use it when really out of breath and tired.  Today I started coughing up phlem with blood in it.  What could be the problem?  I had lung cancer 8 years ago but with 6 months of chemo & 3 months of radiation.  Tumor gone. Any info on current problem appreciated.
Thanks

[National Jewish]

There can be irritation in the airways of your lungs with chronic obstructive pulmonary disease (COPD), bronchitis, and oxygen use.  This irritation can cause some blood to leak from the blood vessels that are close to the surface of the inside of the airways.  This may appear as blood streaked phlegm.  However, you would want to be sure that your past lung cancer is not part of the problem.  Please see your doctor to know what is causing the blood in the phlegm that you are coughing up.

[starion]

I'd suggest you made a note of when it occurred (dates & times), the color of the blood (bright red, dark red, etc.) and estimate the amount of blood (in teaspoons or tablespoons).  It would be good to call your doctor during his/her office hours and report it, particularly if it occurs for more than one day or appears to be a large amount of blood.
Sometimes it's related tou nasal irritation, sometimes an infection, sometimes more.  It's best for your doctor to help determine how serious a situation it may be.
Good luck!
Starion