Is Ovarian Cancer Related To Severe Constipation?

my mother is 62 yrs old and has not been able to go to the bathroom for about 2-3 weeks now. She went to see her doctor and they took bloodwork to see if she might have ovarian cancer. What does that have to do with the bowls and she has taken more fiber, laxatives and enima's as well and still nothing. could she have a blockage somewhere? could there be something else wrong?