The rate of breast cancer recurrence is much lower among women of Japanese descent than among women in the general U.S. population, a study from Hawaii suggests.

Dr. Mark Kanemori and Maria Prygrocki from Kuakini Medical Center, Honolulu, assessed outcome data on 896 women with breast cancer who underwent lumpectomy and radiation therapy. Six hundred seventy-one of the subjects were of Japanese origin.

The researchers found that only six patients had a local in-breast recurrence - just 0.67 percent.

“Because recurrence rates usually increase with longer follow-up, a subset analysis was performed to evaluate only patients who had at least 5 years of follow-up,” the investigators write. They identified a total of 504 patients who had been followed for an average of 8 years, and in this group the in-breast local recurrence rate was still only 1 percent.

The team notes that the survival data from the Kuakini Medical Center were superior to rates recorded in the National Cancer Data Base for each stage of disease.

“There may be something unique in our patient population to explain this remarkably low rate of recurrence,” said Kanemori. “One possibility is that our patient population was composed of 74 percent of patients of Japanese ethnicity.”

Further research to attempt to explain “this uniquely low rate of recurrence ... may reveal prognostic factors that can be used to improve our selection of patients for appropriate treatments in the future,” Kanemori noted.

SOURCE: International Journal of Radiation Oncology Biology and Physics, May 2005.