Severe pain can occur when a cancer spreads to the bones. Now, new study results indicates that a single dose of radiation is a suitable alternative to the 10 daily doses that is usually given to control such pain.

Although the single-dose approach increases the odds of needing repeat treatment, it’s better tolerated with fewer side effects than the multiple-dose approach.

The findings, which appear in the Journal of the National Cancer Institute, are based on a study involving 898 patients with breast or Prostate cancer that had spread to the bones, causing moderate to severe pain.

The subjects were randomly selected to receive the single or the multiple dose protocol. With the former, 8 Grays of radiation is given, whereas with the latter a total of 30 Grays is given over the treatment period.

Seventeen percent of those in the multidose group experienced moderate-to- severe side effects during treatment compared with 10 percent in the single-dose group, Dr. William F. Hartsell, from Lutheran General Cancer Center in Park Ridge, Illinois, and colleagues report. The long-term side effect rate, however, was about the same in each group, around 4 percent.

Overall, 66 percent of patients experienced an improvement in their pain and no significant differences were seen between the groups in complete or partial response rates, the investigators found. One third of all patients no longer required narcotic pain relievers at 3 months.

The percentage of patients that experienced cancer-related fractures was about 4 percent in each group.

The percentage of patients requiring retreatment in the single-dose group was 18 percent, twice as high as the rate in the multiple-dose group, Hartsell and colleagues point out.

In a related editorial, Dr. Lisa Kachnic, from Boston University, and Dr. Lawrence Beck, from Central Ohio Radiation Oncology in Columbus, comment that together with two other studies, the current report demonstrates that single-dose radiation therapy is sufficient to control the pain from cancer that has spread to the bones. “It remains to be seen if this approach will become the standard of care in the US.”

SOURCE: Journal of the National Cancer Institute, June 1, 2005.