Treatment for early stage breast cancer can involve dozens of radiation treatments over a month or more, but a clinical trial now underway may shorten that to a single dose.
Dr. Asal Rahimi says one option for early stage breast cancer is breast conservation therapy: preserving the whole breast versus a mastectomy to remove it. Standard radiation is typically four to six and a half weeks of daily radiation, five days a week.
“Little doses of radiation every day have been effective,” said Rahimi, associate professor, director of clinical research and a member of the Harold C. Simmons Comprehensive Cancer Center. “The radiation is kind of like cleaning up any mess that hasn’t been removed and that we can’t see on imaging. It has been proven to help with decreased local recurrences.”
Rahimi says a clinical trial’s now underway to reduce treatment for early stage breast cancer to a single dose — a game changer for patients.
“It’s convenience,” she said. “It allows people to get back to their life sooner. When you think about all the responsibility women have these days, coming to the radiation facility every single say for six and a half weeks can be burdensome.”
On the clinical trial: Several years back, our group published a radiation schema where patients would get treatment for five days, and this would be partial breast, which is essentially the lumpectomy cavity. We’ve had positive results with that study, and so, the ongoing study that we have right now is one single dose of radiation after surgery to a small area, where the lumpectomy was and the tumor was removed. It would be equivalent to what you would get with the whole six and a half weeks of radiation — except we would be doing it to a much smaller area.
How a single dose became possible: In the '90s, people began looking at treating a focused area of the breast. The next thing that was looked at was intraoperative radiation, where you can bring a specialized radiation machine into the operating room and deliver one dose of radiation at the time of surgery. The downside is that you don’t have the final pathology.
Sometimes people will get this radiation dose in the hospital room and then we find they have positive lymph nodes, or it seems to be a bigger tumor than what we originally thought, or that we have positive margins, so then they have to come back and get whole breast radiation.
This one-fraction study is using that intraoperative radiation as a basis, but we’re trying to make it convenient for everybody on the team, because we’ll have the final pathology and we’ll be able to make these decisions after we really know what’s going on in the breast and how the surgery pathology margins turn out and making sure patients don’t have positive lymph nodes.
Best early stage patients for single dose: This is for patients who have estrogen and progesterone-positive tumors or hormone-positive tumors and they fall within a certain size criteria — really kind of small tumors. But the surgical cavity also needs to be small and that’s to minimize toxicity.