To be honest, the answer to your question is probably a yes and a no.
Anyone who thinks chiropractic is the be all and end all of treatment is a nutcase. There was a girl who went to college with me who thought chiropractic treatments would cure/avoid such things as even strept throat, colds, the flu, etc. (then again, she claimed she had never had any of those in her lifetime - her dad was a good chiropracter.) Still, I doubt it.
On the other hand, I had frequent headaches... daily or every other day. I had pretty much traced it back to a rear-ending accident (I was hit from behind). I could always feel a small lump on the back of my neck. After the treatment, that "lump" that I thought was normal was gone. And, since those visits, I rarely end up with headaches. (in fact, I can only recall using Tylenol 3 or 4 times this school year - I keep it in my desk and usually wipe out a few hundred Tylenols a year. Twice, it was to keep a fever down.)
So, in my experience, yes, a good chiropractor may be able to offer some relief from pain due to misaligned vertebrae. But, as far as curing cancer.... call me skeptical at best.