It really depends. An experienced practitioner can make an educated guess; but only God knows for sure. In many cases, even when acupuncture cannot help the disease directly (such as in cancer), it can be used as an adjunct therapy to relieve the side effects of the main therapy or for tonification or strengthening of the body or to boost its immune system.
According to American Academy of Medical Acupuncture:
"I generally tell patients that if their treatment, according to a Western diagnosis with options, isn't resolving the problem, is quite expensive, or has significant side effects/hassles associated with it, then clearly acupuncture is worth a try. I include the Western diagnosis criteria because I think, as just an example, it is ridiculous to treat someone's dizziness with acupuncture if what they need is to have excessive wax cleaned out from their ear canals. On the other hand, if one is having difficulty controlling or improving one's asthma with Western treatments, a trial of acupuncture makes utmost sense."
