Approximately one-third of patients irradiated annually can be treated with proton therapy, which would result in a 20 percent increase in costs across the entire cancer patient population, according to a study published in the July edition of Journal of the American College of Radiology.

Although proton therapy has seen an increase in utilization, it "is thus far a limited and an expensive resource," said authors Tomas Dvorak, MD, from the department of radiation oncology at Tufts Medical Center and Tufts University School of Medicine in Boston, and David E. Wazer, MD, of the department of radiation oncology at Rhode Island Hospital and Brown University School of Medicine in Providence, R.I. While they noted that the treatment option offers improved tumor coverage and decreased likelihood of normal tissue toxicity, “market-driven adoption of proton therapy into routine clinical practice may have a significant economic impact."

The researchers reviewed the records of all patients treated with highly conformal photon radiation therapy at the facility between Jan. 1, 2007, and Dec. 31, 2007, using photon therapy as a substitute to estimate the proportion of patients who could potentially be treated with proton therapy. The treatment techniques were categorized using CPT codes, as conventional radiation therapy, intensity-modulated radiation therapy (IMRT), Gamma Knife radiosurgery, stereotactic body radiation therapy and brachytherapy. The authors leveraged 2008 Medicare codes to estimate the cost impact.

All 1,042 patients were treated with 1,145 radiation treatment courses and 19,749 treatment fractions. Highly conformal external-beam photon techniques, serving as a stand-in for proton therapy, were delivered in 31 percent of all fractions with IMRT in 30 percent, stereotactic body radiation therapy in less than 1 percent and Gamma Knife radiosurgery in 1 percent of the fractions.

The researchers determined that most of the treatment fractions were used for prostate cancer (37 percent), gliomas (17 percent) and head and neck cancers (16 percent). Pediatric patients accounted for 2 percent of all treatments.

“Proton therapy, if delivered instead of highly conformal photon therapy, could increase annual cost for radiation therapy at [Rhode Island Hospital] by $1.3 million (22 percent) and require approximately 1.4 gantries to deliver,” offered Dvorak and Wazer.

Listing several limitations to their study, the authors noted that Medicare reimbursement rates differ across regions in the U.S., and only Rhode Island data were included in the research. In addition, different facilities may have different patient mixes and different utilization rates of highly conformal photon therapy.

Researchers plan further study, which will include “exploring the issue of true patient eligibility and potential proton utilization in this setting in further detail by using existing clinical literature and evaluating each treated patient individually as a potential candidate for proton therapy.”