THC has shown tumor-inhibiting effects. The other stuff, carbon monoxide and the like however could stimulate tumor growth into cancer. Statistically you may be more likely to have been a person who would've had cancer and then not get it than be a person who otherwise wouldn't have gotten cancer and then get it, but technically it can still give you cancer. There's lots of factors at work, including random chance.
While I'm in the "legalize it" group, yes, it can. You're not only inhaling smoke, but smoke that the intent is to hold in for an extended period to maximize the effect of. While the dangers of marijuana are overstated and discredited by many, yes, holding smoke in your lungs isn't good for you and cause problems.
I believe that using natural plants such as marijuana will not give you cancer. I think it is all the additives and preservatives that can be found in almost everything these days is what can give you cancer. Many additives have been shown to be toxic. I don't think that marijuana would be prescribed to patients medicinally if it caused cancer.
I do not believe that marijuana can cause cancer. There have actually been documented stories that prove this; some people who smoke marijuana can actually live longer. There are no harmful chemicals in marijuana that could/would cause people to get cancer. Holding smoke in your lungs may not be good, but there is no evidence that smoke alone causes cancer.
No, marijuana cannot cause cancer. Smoking is not healthy but pot is an herb, a plant. It is totally natural and does not contain anything toxic that will harm you to that degree. I do not support the use of this drug, but it cannot cause this type of illness directly.