Partial breast radiation now common for some early-stage cancer patients

In November 2023, the American Society for Radiation Oncology (ASTRO) updated its 2017 guidelines recommending partial breast irradiation (PBI) as an alternative to whole breast irradiation (WBI) in women with ductal carcinoma in situ (stage 0 breast cancer) and early-stage invasive breast cancer (stage 1 breast cancer).

The research found that treatment with partial breast radiation provides equivalent survival and low rates of recurrence as treatment with a total mastectomy. An additional benefit is breast preservation.

The practice is already in place at the Clark Cancer Center at Falmouth Hospital and at Davenport-Mugar Cancer Center at Cape Cod Hospital in Hyannis, said Molly Sullivan, MD, a radiation oncologist at the two centers.

“We started using partial breast irradiation four years ago,” she said. “The COVID-19 pandemic made radiation oncologists across the United States look hard at what we were doing. We wanted to minimize patient exposures coming in and out of the hospital, so it made us look at treatment regimens where we could treat patients faster and not compromise breast cancer control within the treated breast.”

The white paper published by ASTRO, following a review of more than 10,000 patients in randomized studies, “confirms that partial breast irradiation is a valid treatment for appropriately selected patients,” she said.

Whole breast irradiation means treating all of the breast tissue from below the head of the collar bone to the inframammary fold, and from the midline to several inches behind the breast, according to Dr. Sullivan. “This has been the standard of care for decades.”

With partial breast irradiation, the tumor bed and a generous margin are treated, she said.

“The surgeons will place metallic clips in the walls of the tumor cavity that can be targeted and identified on the radiation treatment machine. We treat that area, which is the primary site, and generally an inch beyond that.”

Treatment Options

Dr. Sullivan explained the two partial breast treatment options the radiation oncologists at the two Cape Cod Healthcare cancer centers use:

“The one we use most often is called ‘accelerated partial breast irradiation’ and involves treating the tumor bed and an inch beyond that every other day for a total of five treatments. We use a higher dose of radiation every day,” she said.

The second regimen is treating the tumor bed Monday through Friday for 15 treatments, she said.

“It’s almost like what we do now for the whole breast but a smaller amount of breast tissue within the radiation field. It’s not an option that I use very often because it does not save as much time,” she added.

Fewer Side Effects

There tend to be fewer side effects from partial breast irradiation than with whole breast irradiation, according to Dr. Sullivan. Side effects may include:

• Some redness in the form of a little band across the breast.
• A burned skin reaction can occur in the inframammary fold from the radiation beam, if the tumor bed is in this area.
• Discomfort in the skin.
• Fatigue.

“Most women tolerate it quite nicely,” she said. “I always counsel patients that they are still going to feel tired and have some discomfort in their breast. You still may have some redness but only in that area and not the entire breast.”

While the new recommendations include ductal carcinoma in situ and early invasive breast cancer, there is still more research that needs to be done, according to ASTRO.

“There is a lot to consider with each woman when deciding the type of treatment to use,” said Dr. Sullivan. “You have to take each patient case by case.”