Recurrence Twice as Likely in Younger Women with DCIS

Ductal carcinoma in situ (DCIS) typically begins in a milk duct and is the most common type of noninvasive early stage breast cancer. It represents nearly one-quarter of new breast cancer diagnoses annually. While DCIS is highly treatable, a group of researchers, led by Iwa Kong, MD, fellow, Department of Radiation Oncology, Sunnybrook Health Sciences Centre and University of Toronto in Canada, determined that the cancer is nearly twice as likely to recur in women younger than 45 years at diagnosis.

“We don’t yet know why younger women with DCIS have a higher rate of recurrence compared with older women,” Dr Kong said. To conduct the population-based study, the researchers searched a database of Ontario women treated for DCIS in 1994-2003 for those aged 50 years and younger at diagnosis. They narrowed the study population down to the 583 women treated with lumpectomy and radiation. Various randomized studies have demonstrated the effectiveness of this protocol in significantly reducing rates of local recurrence.

The authors were concerned that few studies included sizable numbers of patients 50 years and younger and some seemed to suggest that younger patients might be more susceptible to recurrence. “Thus, we asked the question, ‘do young women with DCIS have low rates of recurrence when treated with lumpectomy and radiation,’” Dr Kong said.

In their retrospective study, 17% (n = 99) of women overall experienced local recurrence, with 6.5% (n = 38) developing invasive local recurrence. Women under age 45 years had an approximately 22% rate of recurrence. The researchers said the typical recurrence rate in women aged >50 years is 10% to 15% within 10 years of diagnosis.

Age at Diagnosis, y

No.

RR, %

≤40

60

23

40-44

184

21

45-50

339

14

RR indicates recurrence risk.

Dr Kong emphasized, “These findings do not imply that all young women with DCIS need to undergo more aggressive surgery, such as a mastectomy, to reduce recurrence risk.” She said further studies were needed to examine other treatments, such as adjuvant tamoxifen or higher doses of radiation.

Lori Pierce, MD, professor of radiation oncology, University of Michigan School of Medicine, moderated the press conference and described the study as very important. She noted that population-based studies do not capture all the information involved in treating the patients, and other factors might contribute to the poorer outcomes seen in the younger patients with DCIS. Abstract No. 127.