By: Dan Sperling, MD
In recent months, proton beam radiation has come under criticism for two main reasons. First, it imposes a huge cost burden upon a medical payment system that is already limping. Second, it has not been shown to be significantly more effective in the treatment of prostate cancer than other forms of beam radiation such as IMRT (Intensity Modulated Radiation Therapy) or stereotactic radiosurgery.
When any form of radiation is used to treat cancer, its effectiveness is based on damage to the DNA of the prostate cancer cells. Unlike ablation, which causes immediate cell death by extreme heat or cold, cancer cells exposed to radiation take time to die off. This is why external beam radiation is offered as a series of daily treatments over a period of weeks, or why radioactive seed implants (brachytherapy) are permanently placed in the prostate gland to create constant exposure to the radiation dose that gradually diminishes. With traditional forms of radiation therapy, which beam electrons, photons or gamma rays at the tumor, there is always some scatter effect on nearby healthy cells. Proton beam was created as a way to generate as little scatter as possible, thus maximizing the effectiveness where it is most wanted.
Proton beam therapy is costly because it relies on a special facility to house a particle accelerator, the technology that targets the tumor with a beam of protons. These charged particles have relatively large mass, which results in limited lateral scatter to healthy tissue. The protons have the same type of effect on the DNA of cancer cells, limiting their ability to reproduce so the tumor eventually dies off. Proton beam can be used to treat many cancers, from tumors close to the skin surface to those deep within the body, which require a greater amount of energy to penetrate further.
Constructing a special building for the accelerator is expensive, as is the technology itself. Recently, the Indiana University Health Proton Center announced that it will close by 2015. In the ten years since the Center opened, it incurred losses in the millions of dollars. A committee of outside experts was appointed to study the situation, and recommended closing the Center. Among other reasons, the panel identified advances in cancer treatments, lower insurance reimbursement levels, and aging equipment. In fact, more proton centers with newer equipment have sprung up, and the IU Center was not in a position to compete with them due to a reduced number of patients being referred for proton beam as a result of the ongoing development of treatment alternatives.
Everyone is worried about increasing healthcare costs. Many people, I am sure, are wondering how medical trends in the U.S. will be affected by financial factors, especially reduced reimbursements. Undoubtedly, there are economic pressures that spur the development of relatively low-cost devices such as those used for laser ablation. What is the future of proton beam, which has shown value in treating brain and pediatric tumors but may prove cost-ineffective for prostate cancer? How the equation will balance out remains to be seen.