SAN ANTONIO, October 29, 2018 -- A subset of patients with low-risk breast cancer is highly unlikely to see cancer return following breast conservation surgery but can lower that risk even further with radiation therapy, finds a new long-term clinical trial report. These 12-year follow-up data from the only prospective, randomized trial to compare recurrence outcomes after treatment for low-risk ductal carcinoma in situ (DCIS) were presented last week at the 60th Annual Meeting of the American Society for Radiation Oncology (ASTRO).

In this long-term update, patients with "good risk" DCIS -- defined by the research team as cancer found only on mammogram or incidentally during a breast biopsy for another reason -- continued to experience extremely low recurrence 12 years after breast conservation surgery. Those who underwent whole breast radiation therapy (WBRT) and those who also opted to take tamoxifen experienced the lowest recurrence rates, but even those who received no further treatment following surgery did not experience any life-threatening consequences.

"I think the most surprising thing was that the recurrence rate in patients randomized to receive radiation therapy was so low. Radiation reduced recurrence by more than 70 percent, and this was a much more profound impact than we expected," said Beryl McCormick, MD, FASTRO, lead investigator of the NRG Oncology/RTOG multi-center trial, Chief of the External Beam Radiotherapy Service at Memorial Sloan Kettering Cancer Center and a professor of radiation oncology at Cornell University in New York.
Since none of the tumors that recurred in either group appeared to pose a life-threatening risk, however, Dr. McCormick said it was reasonable for patients to determine, in consultation with their physician, whether continued treatment following surgery was something they wanted to do.

"Not all DCIS is the same," said Dr. McCormick. "This type of cancer will not impact life expectancy. We found that radiation does significantly reduce the risk for recurrence, but you are starting with an extremely low recurrence rate even without radiation. Therefore, there should be a meaningful discussion between patient and doctor about whether additional treatment is something the patient wishes to pursue."

DCIS is a cancer of the cells that line the milk ducts of the breast. It accounts for roughly one-fourth of all new breast cancers for an estimated 60,000 cases diagnosed in the United States each year. The current standard of care for DCIS includes lumpectomy to remove the tumor in combination with radiation therapy to reduce the likelihood that the cancer will return.

Operating Room Homepage