How common is radiation cystitis?

It is common: When we give radiation near the bladder or to the bladder it is fairly common. This only means an inflammation of the lining of the bladder. Radiation can irritate this lining and therefore the patient feels a sensation on urinating. It can be as little as just noticing it, frequency or frank burning. We have medication to ease this symptom and after radiation is complete it usually goes away.

Depends on Target: The amount of bladder radiated determines the severity of the symptoms. If you are treating bladder cancer then the bladder is the target, so the incidence would be higher. For prostate, gynecological, and rectal cancer the incidence will depend on the amount of bladder (volume) and the dose delivered to that volume.