INTRODUCTION:
Proton therapy or proton beam therapy is a radiation treatment for patients who have cancer. Instead of x-rays, protons are used. Protons are positively charged particles and at high energies can destroy cancer cells. Doctors can just use proton therapy or combine it with standard radiation therapy, surgery,
chemotherapy, and/or immuno-therapy. Standard x-ray radiation therapy, proton therapy is a type of
external-beam radiation therapy. It painlessly delivers radiation
through the skin from a machine outside the body. (A)Proton-beam therapy is a form of cancer radiotherapy that uses positively charged particles to kill tumor cells. Unlike traditional radiotherapy using X-rays, protons can be programmed to deposit most of their energy in the tumor, minimizing damage to surrounding, healthy tissue. X-rays, in contrast, lose energy as they move through the body, meaning that tissue between the tumor and the beam will receive a higher dose of radiation than the tumor itself. The technology has been around since the 1980s, but until recently demand was muted due to high cost and limited evidence that it makes financial sense. Proton-beam therapy centers can cost up to $200 million to build and are more expensive to operate than traditional radiotherapy. (B)
BACKGROUND INFORMATION:
The way in which proton therapy works is with a synchrotron or cyclotron which speeds up the protons. The speed of the protons reflects their high energy. The protons travel
to a specific depth in the body based on their energy. Once these protons reach the targeted region in the body, they then deposit the specified radiation dose in the tumor. Treatment with proton therapy lacks any further radiation beyond the region of the tumor. Whereas, x-rays continue to deposit radiation doses as they exit the patient's body. This means that
radiation is also damaging nearby healthy tissues, potentially causing
side effects. (A)Patients that undergo proton therapy do not need to have hospital admission (aka: they are in an outpatient setting). The number of sessions depends on the type and stage of the cancer. Physicians can give proton therapy to their patients from one to five proton beam treatments. Generally they use larger daily radiation does which is known as 'stero-tactic body radiotherapy'. If a patient recieves a large single dose of radiation it is known as radiosurgery. Proton therapy helps to treat tumors that have not spread yet and for tumors that are located close to important organs or regions in the body (i.e. eye, brain, and spinal cord). Children are often treated with proton therapy because their tissues are still developing and this form of therapy is least harmful. Children can have proton therapy for brain, spinal cord, and eye cancers such as retinoblastoma and orbital rhabdomyosarcoma.
TREATMENT:
Proton
therapy can be used to treat central nervous system cancers, including
chordoma, chondrosarcoma, and malignant meningioma / Eye cancer,
including uveal melanoma or choroidal melanoma/ Head and neck cancers,
including nasal cavity and paranasal sinus cancer and some
nasopharyngeal cancers/Lung cancer/Liver cancer/Prostate cancer/Spinal
and pelvic sarcomas, which are cancers that occur in the soft-tissue and
bone/Noncancerous brain tumors.Compared with standard radiation treatment, proton therapy has several benefits Up to 60% less radiation generally can be delivered to the normal tissues around the tumor, which lowers the risk of radiation damage to healthy tissues. It may allow for a higher radiation dose to the tumor, which increases the chances that all of the tumor cells in the tumor targeted by the proton radiation will be destroyed. It may result in fewer and less severe side effects such as low blood counts, fatigue, and nausea during and after treatment.
DRAWBACKS:
However, there are some drawbacks because proton therapy requires highly specialized, expensive
equipment, it is available at just a few medical centers in the United
States. It may cost more than conventional radiation therapy.
Insurance provider rules vary about which diagnoses are covered and how
much patients need to pay. Talk with your insurance provider to learn
more. Not all cancers can be treated with proton therapy.Several ongoing randomized controlled clinical studies are comparing x-ray treatments to proton treatments. These are being conducted for several reasons in organs where the tumor and the adjacent normal tissues are moving, such as the lung, there may be a higher risk of not giving a large enough dose when compared with x-rays. In other areas of the body, sophisticated x-ray treatments produce excellent results with a low risk of significant radiation-associated side effects. For these tumors, clinical studies are needed to find out whether proton is better than x-rays, given the higher cost of proton therapy. (A)
CONTROVERSY:
Why is proton therapy so expensive and why is there so much controversy about this form of cancer treatment? Ion Beam Applications SA,the Belgian company that leads the
global market for huge
proton-beam machines, is selling so many systems lately that it needs to
boost its 1,200-strong workforce by 400 workers. It launched a big
recruitment drive across the country this year, featuring radio and
newspaper spots along with dozens of billboards and posters. (B)
While that higher price tag is justified for
treating childhood cancers and a small number of adult cases, such as
tumors in the base of the skull, the jury is still out on its
cost-effectiveness for most common cancers. For a long time it was cheaper for countries to send their patients abroad for treatment. The U.K., since 2008, would send its patients to US. There has been much controversy over proton-beam therapy because hospitals did not want to make a multi-million dollar bet on new technology that had little and weak evidence. However, without these treatment centers, it's impossible to do further research and to get more evidence to support this technology's results. (B)
RESEARCH:
A 2013 study estimated that for prostate
cancer patients, proton therapy cost $32,428 per treatment, versus
$18,575 for traditional radiotherapy. But advocates believe proton
therapy could prove less expensive than traditional radiotherapy in the
long term by cutting costs for treatment of side effects from
traditional radiotherapy.Guidelines issued in 2014 by the American Society for Radiation Oncology also helped bolster the case for proton-beam therapy. They recommended that health-care insurers cover proton-beam therapy for all forms of cancer patients—not just those for whom the treatment has a proven cost-benefit—if they are participating in a clinical trial.
Todd Ketch, executive director of the National Association for Proton Therapy, an industry body, said that insurance coverage for proton-beam therapy in the U.S. was mixed. While some insurers “clearly value both the short- and long-term benefits of proton therapy for certain patients fighting cancer,” others require patients to “navigate daunting administrative approval and appeals processes to obtain coverage,” he said.
Justin Bekelman, a radiation oncologist at the Hospital of the University of Pennsylvania, which has been using proton-beam therapy since 2010, said the treatment had “tremendous potential, but we haven’t finished our work to demonstrate what it can do.” He added: “I can never imagine a world without proton therapy at this point, but I’m not convinced it’s better for everything we do.”
(A) http://www.cancer.net/navigating-cancer-care/how-cancer-treated/radiation-therapy/proton-therapy
(B)http://www.wsj.com/articles/proton-beam-therapy-for-cancer-gets-renewed-attention-1463428188
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