The TARGIT process is a subset of what is called partial-breast irradiation, which is itself still controversial. While many experts believe so-called accelerated PBI is valuable, most say they will remain cautious until the results of a definitive trial now under way are available.
With the TARGIT approach, at least three forms of accelerated PBI are being tested:
In TARGIT, the surface of the tumor bed is given a low dose of X-rays for between 20 and 35 minutes after the tumor is removed and before the wound is closed. No other radiation is intended to be given, although in the study 14 percent of women also got additional external beam radiation.
In 3-D conformal external beam radiation, beams of radiation are computer-guided to hit just the tissue that doctors think needs it. The radiation is typically delivered over five days.
In balloon brachytherapy, a small balloon is inflated to fit snugly in the space left by the tumor, connected with the surface of the breast with a catheter. Over a five-day period, a radioactive seed is placed in the balloon for a period of time each day to deliver the radiation.
Although all three remain experimental, many centers offer 3-D conformal external beam radiation or balloon brachytherapy when whole breast radiation for several weeks is difficult or impossible for women.
The difference, according to Dr. Jay Harris of Brigham and Women's Hospital in Boston, is that those approaches have "reasonable data" to support them. "Single intraoperative APBI does not," he said.
Indeed, even when those approaches are offered, physicians are careful to counsel that they remain experimental.
The Moffitt Cancer center in Tampa uses both APBI approaches, according to radiation oncologist Dr. Eleanor Harris. Patients who seek either form are "counseled that APBI is not the standard of care, that there is a lack of long term outcome and toxicity data and that equivalent results to whole breast irradiation cannot be guaranteed," she said in an email.
Harris said the Lancet study "makes a strong case" for some patients to get the intra-operative therapy, but she also noted that "follow-up is short."
Moffitt currently doesn't have the equipment for the TARGIT approach, although it plans on getting it. On the other hand, Harris said, "the vast majority, if not all, patients" treated with the approach will be part of clinical trials.
Dr. Thomas Julian of Allegheny General Hospital in Pittsburgh said that current therapies successfully delay both local and systemic recurrences in early stage breast cancer, meaning that a short follow-up might not reveal differences in outcomes.
The TARGIT data is "premature," he said in an email, but the outcome of the NSABP study -- Julian is a senior official on the trial -- will "answer questions that will change standards of care."
"I am not ready to recommend PBI outside of a trial for routine therapy in place of [whole breast irradiation] until the long term outcome data are available," Julian said.
That opinion was not completely universal. Dr. Stefan Glück of the University of Miami's Leonard M. Miller School of Medicine, said in an email that he and radiation oncologists at his institution are prepared to recommend PBI, although he did not comment specifically on TARGIT.
And Dr. Susan Love of the Dr. Susan Love Research Foundation, said: "I do think these findings are practice-changing."