Questions and answers

How will Mayo choose which patients receive proton therapy?

As with all medical decisions made at Mayo Clinic, a team of physicians and specialists will review eligible patients. Children, young adults and healthy older adults with potentially curable cancers located next to sensitive critical organs will be given the highest priority.

Isn't intensity-modulated radiation therapy (with X-rays) just as effective as pencil beam scanning (with protons)?

Pencil beam scanning allows a more precise dose of radiation by "painting" the tumor with protons, which limits radiation to surrounding healthy organs. Pencil beam scanning uses a beam that is much smaller than that used for traditional proton treatments. The experience at Paul Scherrer Institute in Switzerland, which pioneered pencil beam scanning, has shown that pencil beam scanning is an advance over traditional radiotherapy (which uses photons) because its beam is targeted only to the tumor. It can therefore be used at higher therapeutic doses and with fewer side effects to surrounding healthy tissue.

Is Mayo Clinic the first institution to employ pencil beam scanning for the treatment of cancer patients?

Only a few treatment rooms in the United States offer this more advanced proton therapy technique. All eight treatment rooms at Mayo Clinic's two facilities will feature this upgraded technology. Mayo will be the first to operate pencil beam scanning facilities in the Midwest and Southwest. Mayo will have the smallest and, therefore, the most accurate, pencil beam in the world.

How many proton beam therapy facilities are there currently in the United States?

According to the National Association of Proton Therapy, there are 11 centers in operation and 13 in development (summer 2013).

What is the current capacity in the United States for serving cancer patients with proton beam therapy?

A conservative estimate is that about 137,000 new cancer patients each year in the United States could benefit from proton therapy. Current capacity is 11,270 patients a year. Mayo Clinic will add capacity for another 2,400 patients a year.

Proton beam therapy is expensive. Is it worth the investment?

The investment will allow many more people to be helped. Mayo believes that these treatments will significantly increase cure rates and reduce long-term side effects, especially in children. While initial treatment costs may be higher, longer term cost of care will be lower, as demonstrated in a Swedish study of children with brain tumors. The facilities are also an investment in research into the next generation of charged-particle therapies and their potential as more effective treatments for a wide range of cancers.

Mayo received a $100 million gift for the proton beam therapy program. Doesn't that cover the costs of this program?

This project wouldn't be possible without this extremely generous gift from a benefactor (in fact, the largest outright gift in Mayo's history). But this is very expensive technology. Mayo's budget for the buildings and the particle accelerators and the staff is about $370 million. This initiative will need broad support from many benefactors to realize this promising new tool and to actually make a difference in the lives of cancer patients.