If I understand your question, you're asking if not having a doctor is an obstacle to access. That's absolutely the case, especially in provinces where you need a requisition to get the screening mammogram.
In Alberta, fortunately, we've moved it down to age 45 when they get invited and can self-refer, but if you want to get in at 40, you need a requisition at least for the first one. If you don't have a doctor or if your doctor believes the task force and does not want to write a requisition, there's a big barrier right there. Yes, that's a huge barrier for a lot of women.