Men diagnosed with localized prostate cancer are more likely to be treated with proton beam therapy, a novel form of radiation therapy, if the technology is available nearby, a new study found.

Prostate cancer is the most common cancer in men - the National Cancer Institute estimates that more than 240,000 men in the U.S. were diagnosed in 2011.

About nine out of 10 of those cases were localized prostate cancer, meaning the cancer hasn’t spread outside the prostate gland. Nearly all men diagnosed with localized tumors survive at least five years after diagnosis.

In the study, researchers examined the treatment choices of nearly 20,000 men living inside or outside of a regional market for Loma Linda University, a hospital in Southern California with a proton beam facility. All men were diagnosed with low- to intermediate-risk prostate cancer between 2003 and 2006.

Currently, there are nine proton centers in operation in the United States and eight more in development, according to the National Association for Proton Therapy.

Touted as a technological advancement over other forms of radiation therapy, proton beam therapy allows radiated particles to more tightly target and destroy tumor cells, leaving more of the surrounding tissue intact.

The treatment is often billed as having lower impotence and incontinence rates than other radiation treatment options, but there’s a lack of evidence to support this, according to Dr. David Aaronson, a urologist at Kaiser Permanente Medical Group in Oakland, California, and lead author of the study.

After taking into account factors such as tumor stage and year of diagnosis, Aaronson’s team found that patients living near a proton beam facility were more than five times more likely to receive proton beam treatment than those living outside of the hospital’s referral region.

Nearly nine percent of the patients living within the referral region for the facility received proton beam therapy, compared to less than two percent of patients throughout the rest of the state.

The researchers also found that younger and non-Hispanic white men were also slightly more likely to receive proton beam treatment.

“It’s not surprising that men are more likely to be treated with a certain technology in an area where that technology is offered,” Aaronson told Reuters Health.

While most insurers, including Medicare, cover proton beam therapy, it comes at a hefty price.

Previous studies have estimated that proton beam therapy costs twice as much as intensity-modulated radiation therapy, another form of external radiation therapy and about five times more than radioactive seed implants.

And side-by-side comparisons of proton beam therapy and other prostate cancer treatments have not been done, according to Dr. Leonard Lichtenfeld, chief medical officer for the American Cancer Society.

Despite the added costs, there’s no evidence to suggest that proton beam therapy results in better outcomes than other forms of prostate cancer treatment, including other forms of radiation, surgery or hormone therapy.

Although proton beam therapy has been shown to be superior in targeting tumors of the brain, eye and spine, those cancers are rare.

Institutions with proton beam facilities often look to pad their numbers by treating prostate cancer, according to Dr. Anthony Zietman, a radiation oncologist at Massachusetts General Hospital in Boston who was not involved in the new study.

“People often think that technology is synonymous with ‘better,’ but in some cases, it’s not,” said Aaronson.

“With the healthcare crisis looming and multiple treatment options available, newer, more expensive procedures for prostate cancer should be validated before they are implemented,” he said.

SOURCE: Archives of Internal Medicine, February 13, 2012

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Proton Beam Therapy and Treatment for Localized Prostate Cancer: If You Build It, They Will Come

David S. Aaronson, MD; Anobel Y. Odisho, MD; Nancy Hills, PhD; Rosemary Cress, DrPH; Peter R. Carroll, MD, MPH; R. Adams Dudley, MD, MBA; Matthew R. Cooperberg, MD, MPH
Arch Intern Med. 2012;172(3):280-283. doi:10.1001/archinternmed.2011.711