If there are cancerous cells in the body, injecting IGF-1 will make them multiply faster. Just as the normal IGF-1 produced by the body does. Cancerous cells are cells that overmultiply. Supplying them with excess IGF-1 makes them behave even more so.
BUT IGF-1 does not CAUSE cancer. Not in women, not in men. If you have cancer you should not be taking IGF-1. Otherwise you're doing just fine.