PALM BEACH, FLA. — Narrow surgical margins and use of core-needle biopsy appeared to correlate with recurrent breast cancer in a series of 223 women with ductal carcinoma in situ who were treated with skin-sparing mastectomy.
The series included seven patients with local recurrences (3%). The seven local recurrences were not found until they were palpable masses detected by the patients themselves, and six of the seven local recurrences were invasive cancers, Dr. Grant W. Carlson said at the annual meeting of the Southern Surgical Association. When the primary tumor was noninvasive, a ductal carcinoma in situ (DCIS), having six of seven local recurrences develop into invasive cancers is “unsettling,” said Dr. Carlson. “This is a potentially curable disease,” he added.
He and his colleagues reviewed the outcomes of all women with DCIS who were treated at Emory University in Atlanta with skin-sparing mastectomy and immediate reconstruction between 1991 and 2003. The average follow-up was 82 months, said Dr. Carlson, a professor of surgery at the university. None of the patients received adjuvant radiation therapy.
During the first phase of the series, suspected tumors were confirmed with a wire-localization biopsy. The most recent 59 patients were diagnosed with stereotactic core-needle biopsy.
A total of 11 patients (5%) had recurrences. Seven of the recurrences were local, two were regional, and two were at distant sites.
The rate of total recurrences and of local recurrences was similar to rates previously reported for women with DCIS who underwent conventional mastectomy.
Dr. Carlson and his colleagues explored a possible link between local recurrence and several potential risk factors. The only significant association they found was between biopsy type and local recurrence. Among women with local recurrences, 71% had undergone a core-needle biopsy, compared with a 25% rate of core-needle biopsies in women without recurrences, Dr. Carlson said.
The investigators did not find a statistically significant link between recurrence and other potential risk factors, including age of 50 or less, tumor size of 40 mm or more, tumor grade, or presence of necrosis in the tumor, although each of these markers was associated with a nonsignificant increase in the incidence of local recurrence.
A greater, nonsignificant link was seen between a narrow surgical margin and recurrence. Surgical margins of 1 mm or less occurred in 29% of women who had local recurrences, compared with 9% of women who did not have recurrences.
As a result of this experience, Dr. Carlson now recommends that women treated with skin-sparing mastectomy for DCIS undergo some form of routine follow-up imaging. Mammography is useful when the images are read by an experienced mammographer who is not misled by the artifacts of a reconstructed breast. An alternative is MRI, which makes it easier to find recurrent tumors early in women with reconstructive implants.
Other measures that Dr. Carlson has instituted are to seriously consider using radiation adjuvant therapy in women whose tumor excisions had narrow surgical margins of less than 1 mm, and to excise the track from the core-needle biopsy to remove any tumor cells that may have leaked into the track.
This report is important because it includes more patients than all of the previously published reports on DCIS recurrences combined, commented Dr. Kelly M. McMasters, chairman of the department of surgery at the University of Louisville (Kentucky).