elevation and radiation

I had radiation therapy three years ago and my doctor warned me about being at high elevations
flying etc...Should I still be concerned and not live in a town I like at elevation 5000?

[Fernando Roque, MD]

Hi.  Your doctor warned you about being in high altitude places while undergoing radiotherapy, probably because radiation treatment has a tendency to temporarily lower your hemoglobin and red cell counts.  This may result in a decreased tolerance for the low oxygen content found in high elevations.  If your radiation treatment happened three years ago, and you haven't had any recent treatment, it's probably safe for you to live in a high altitude town.

[HeinrikMD]

Hi,
Its difficult to say what was meant by your doctor.
High elevation is associated with lower oxygen tension, which would trigger an increase in red blood cell production. Whether it will also trigger an increase in growth of cancer cells is plausible but not clearly proven. There are some studies in mice, but the results are inconclusive/contradictory.
Looking at populations in general without considering any history of radiotherapy, there is actually a decrease in incidence of total lung cancers among people living in higher altitude. The reason being implicated is increased oxygen available at lower altitudes (which actually runs contrary to the theory of increasing growth of cancers given above).
Put another way, too much oxygen may promote appearance of cancer cells, too little oxygen may promote growth of cancer that already exists. Extracting risk from mice or from large populations to apply to an individual is difficult if not impossible.  
At the end of the day, there is a reason to believe that either scenario can be deleterious but not compelling to use to decide about a very important decision.
Best to inquire specifics from your doctor. If you had lung radiation and your lungs are less than optimal - you may have difficulty with higher altitudes. However, this is a question of lung function, and if you seem to tolerate breathing over the 5000 elevation area, then you should be fine.