Tumor size may not dictate radiation

LA JOLLA, Calif., Dec. 31 (UPI) -- Early stage breast cancer that hasn't invaded surrounding tissues may contain highly mobile cells, increasing metastasis risk, a U.S. study said.

The study, published in the Journal of Cell Biology, suggested that the highly motile cells, although not yet invasive, could wander off along milk ducts and seed new tumors within the same breast.

Lead author Gray Pearson, a postdoctoral researcher at the Salk Institute for Biological Studies, said the standard treatment for ductal carcinoma in situ, or DCIS -- the most common site where invasive breast cancer arises -- is lumpectomy, the surgical removal of the tumor and surrounding tissue.

Approximately 16 percent of DCIS patients treated with lumpectomy alone develop recurrent breast cancer growth within five years of treatment, Pearson said. Currently, the decision on whether to add radiation after undergoing surgery to catch straying tumor cell is based on the size of the tumor.

"Our findings suggest that, if a DCIS contains these highly motile cells, the patient may have an increased risk for recurrent growth," Pearson said in a statement. "Under these circumstances you would consider adding radiation treatment regardless of tumor size."