Radiation Not Needed for Some Ductal Carcinoma In Situ

December 16, 2006

SAN ANTONIO -- Some women with ductal carcinoma in situ (DCIS) can safely skip radiation therapy and be treated with lumpectomy alone, a researcher said here.

SAN ANTONIO, Dec. 16 -- Some women with ductal carcinoma in situ (DCIS) can skip radiation therapy safely and be treated with lumpectomy alone, a researcher said here.

The five-year risk of recurrence for women with small, low- to intermediate-grade tumors is about 6.1% if they do not have radiation therapy after surgery, according to Lorie Hughes, M.D., of Emory University in Atlanta.

Many physicians and women would regard that level of risk as "acceptable" if it meant they could avoid the cost and adverse effects associated with radiation, Dr. Hughes told the San Antonio Breast Cancer Symposium.

The finding -- derived from a five-year follow-up in a 10-year non-randomized, single-arm study -- essentially begins to build a scientific foundation for what is an increasingly common practice in the oncology community, Dr. Hughes said.

"We know that a lot of patients are being treated with excision alone," she said. "We were trying to quantitate what level of risk of recurrence they will be looking at, so physicians can better counsel patients."

In contrast, however, women with high-grade tumors -- defined as nuclear grade three with 2 mm to 3 mm of necrosis in the lesion -- had a five-year recurrence risk of 14.8%, a level Dr. Hughes said is probably too high to skip radiation.

In those cases, she said, "I'd be pretty reluctant to omit it."

She added that randomized clinical trials have shown that radiation reduces the risk of local recurrence by between 50% and 75%.

The E5194 study, supported by the National Cancer Institute, studied 680 women, 579 of them with a low- or intermediate-grade tumor. Tumors had to be larger than 3 mm in diameter and less than 2.5 cm for women with low- to intermediate-grade cancer.

Women with a high-grade tumor were eligible if their lesion was less than 1 cm in diameter, she said. The study did not enroll a large number of women with high-grade cancers, she said, probably because their doctors preferred to use radiation.

"I think people were voting with their feet," she said.

The median age of women in the study was 60 and median follow-up was 5.4 years. There was no significant difference in overall survival and the rate of new cancers in the contralateral breast between the low-, intermediate- and high-grade groups, she said.

Dr. Hughes said she's not concerned that the study was not randomized and was lacking a comparator arm, because it is simply attempting to understand the risks associated with a common practice.

That's its value to doctors, according to Richard Elledge, M.D., of Baylor College of Medicine in Houston, who moderated the session in which Dr. Hughes presented her data.

"At least it gives you some numbers to discuss with patients," Dr. Elledge said. "It's a prospective study, well-defined and well followed-up," he said.

If there's a limitation, he said, it's that the five-year follow-up is still only halfway through the study.