A clinical trial of partial-breast irradiation (PBI), slated to start in late summer 2004, will test whether this technique is equivalent to radiation treatment of the whole breast.

For early-stage breast cancer, lumpectomy followed by whole-breast irradiation (WBI) is an alternative to mastectomy. But it took 20 years of follow-up data to establish the scientific basis for lumpectomy. Now, PBI must be tested with similar scientific rigor. PBI often involves approximately one week of radiation treatment vs. six weeks of daily radiation for WBI.

Since traveling to treatment may be a hardship for some women, the shorter duration of PBI is appealing. “Many women are seeking out this treatment,” said Dr. Paul Wallner of NCI’s Radiation Research Program, especially since the Food and Drug Administration (FDA) approved a PBI device in 2002.

The FDA, which based its decision on a study involving 25 women, declared the apparatus safe. The agency did not comment on the ef- ficacy of PBI for treating breast cancer. “We still don’t know what types of patients are best suited to PBI, how much radiation to use, how much breast tissue to target, or if the end results will be equivalent to WBI,” said Dr. Wallner.

In the Feb. 4, 2004, Journal of the National Cancer Institute, Dr. Wallner and colleagues detail issues that need to be addressed before PBI can become standard practice. A clinical trial dealing with these issues will be sponsored by NCI’s Cancer Therapy Evaluation Program. Dr. Frank Vicini, of Michigan’s William Beaumont Hospital, will head the multisite, 2.5- year study of 3,000 women.