Source: Urology  |  Posted 5 years ago

By Charlene Laino

SAN ANTONIO, TX -- December 18, 2006 -- About 6% of women with good prognostic markers after lumpectomy for ductal carcinoma in situ (DCIS) develop recurrences if they do not receive radiation, researchers reported here at the 29[^]th[] Annual San Antonio Breast Cancer Symposium (SABCS).

"Radiation after lumpectomy is the gold standard for treatment in these cases," said Lorie Hughes, MD, clinical associate professor of medicine, Emory University, and radiation oncologist, WellStar Kennestone Hospital, Marietta, Georgia. "In doing this study we wanted to capture outcomes among those women who opted not to undergo radiation."

In women with DCIS low- to intermediate-grade level of risk, the recurrence rates were 6.1% in the ipsilateral breast and 3.7% in the contralateral breast after 5 years, said Dr. Hughes.

"I think we can say that if these women would have had radiation, these rates would have been halved," she said. "Numerous clinical trials have shown that radiation decreases the risk of recurrence by about 50%."

The study was conducted y researchers in the Eastern Cooperative Oncology Group and the North Central Cancer Treatment Group. The goal was not to revisit the effectiveness of radiation but to give doctors facts and figures to discuss with women who were considering not undergoing radiation after surgery.

"I think that a 6.1% recurrence rate is acceptable," Dr. Hughes said. However, the 14% recurrence rate seen in patients with high-risk cancer would not be considered acceptable, she said in her plenary oral presentation on December 16[^]th[].

In the study, 606 patients with low-grade, low-risk cancers underwent lumpectomy surgery but did not receive adjuvant radiation therapy. About 31% of the women took tamoxifen after surgery. The trial was begun in 1997 and was modified in 2000 to allow tamoxifen treatment.

In the study, the researchers enrolled patients into 2 groups: low- or intermediate-grade DCIS (< 2.5 cm), or high-grade DCIS (< 1 cm). The average age of the women in the study was 60 years.

A postexcision mammogram negative for residual suspicious calcifications and final margins greater than 3 mm were required for enrollment in this study.

Only 105 women were enrolled in the high-risk group of patients. Dr. Hughes said the trial was halted at that point due to slow accrual. She said it appeared that most women and their physicians were not willing to risk surgery without radiation in these women.

Overall survival was 98% in the high-risk patients and 96% in the low-risk patients, a nonsignificant difference. Relapse-free survival was 79% in high-risk patients and 85% in low-risk patients, also a nonsignificant difference.

None of the patients in the study died of breast cancer, Dr. Hughes said.

"The key to this study is meticulous pathological assessment of the tumor tissue," Dr. Hughes said.

The study was funded by the US National Cancer Institute. The patients will continue to be followed for another 5 years.

[Presentation title: Five Year Results of Intergroup Study E5194: Local Excision Alone (Without Radiation Treatment) for Selected Patients With Ductal Carcinoma in Situ (DCIS). Abstract 29]