Sorry -- didn't mean to be confusing. But new posters here are urged to get to an NCI-designated CCC (as Kelly did for you on the first page, which he posted while I was writing my reply). In NCI-speak, the terms "comprehensive cancer center" and "cancer center" have specific meanings dealing with research interests -- so you might feel that you should look only at the places the NCI calls "comprehensive cancer centers." Any facility on that NCI-designated list (apart from the few that only do research and see no patients) will take a "comprehensive" approach to patient care, bringing in a variety of specialists to develop a treatment plan.
Your mom should simply tell her doctor that she wants a second opinion. If he balks or gets defensive, he's not the person who should be treating her. Good physicians will welcome the views of more experienced colleagues who deal only with this disease every day.
You should not need a referral -- and should not wait for her next appointment in a week to get things started. The
M.D. Anderson website, for example, has a link in the upper right part of the home page for patients or family members to request an appointment, along with a phone number for appointments. The websites of the other centers I mentioned have similar links and phone numbers. Be sure to ask what they need to see in terms of lab reports, doctors' notes -- even the slides taken from your mom's surgeries.
If you want to keep the current doctor's office in the loop from the beginning (rather than starting the process now but not telling them until your mom's appointment next week), call today and tell them she wants a second opinion and see if they have contacts at one or more of these places who can help move things along -- though at facilities that see a lot of referrals, things tend to move quickly anyway once initial contact is made.