New research shows that most recurrences of ductal carcinoma in situ (DCIS) in the same breast bear a close genetic relationship to the initial lesion.
These results are presented in the February 16 issue of the Journal of the National Cancer Institute by Frederic Waldman, M.D., Ph.D., of the University of California, San Francisco, and colleagues, who conclude that their findings emphasize the need for adequate treatment of the first lesion.
DCIS, considered a precursor of invasive breast cancer, is found in increasing numbers as a result of the growing use of mammography. The usual treatment is breast-conserving surgery, often followed by radiation therapy. However, the incidence of a second DCIS in the same breast after treatment may be as high as 25%.
The authors worked with tissue samples from both an original DCIS and from same-breast recurrences from 18 women, with an average age at first diagnosis of 52.6 years. Breast-conserving surgery was the only treatment for 15 of these cases. Two women had both surgery and radiation therapy, and one woman had surgery but radiation therapy was unknown. Mean time to recurrence of the DCIS was 4.2 years, with a range of 16 months to 9.3 years.
DNA was isolated from stored samples of the DCIS tissues, and a technique called comparative genomic hybridization was used to compare genetic changes in both the original and recurring DCIS tissues. Of the 18 pairs of specimens, 17 showed strong agreement between the chromosomal alterations found in both the original and in the second DCIS. The most common changes in both the initial and recurrent in situ lesions were gains involving chromosome 17q and losses involving chromosomes 8p and 17p. The degree of agreement was independent of the time interval before recurrence and of the presence of positive surgical margins. In addition, there were striking similarities in the microscopic appearance of the paired lesions.
The authors conclude that most DCIS recurrences result from growth of persistent neoplastic cells, which may remain indolent for long periods. The authors conclude that these data suggest the importance of wide surgical margins and/or radiation therapy as part of initial treatment. Further insights into the genetic determination of preinvasive histology and biology will allow treatment that is tailored to the likelihood of clinically aggressive tumors, they said.
In an editorial, Edwin Fisher, M.D., and Bernard Fisher, M.D., of the National Surgical Adjuvant Breast and Bowel Project (NSABP), Pittsburgh, PA, question the statement by Waldman et al. that surgical margins must be at least 10 mm wide. According to the editorial writers, it has not been proven that one specific measurement of the width of tumor-free breast tissue that should surround an excised tumor is better than another. They note that it is wrong if such a policy results in a mastectomy or impairs the cosmetic results of lumpectomy. They conclude that, at present, there is no justification for the use of comparative genomic hybridization as a guide to treating DCIS.
Contact: Leslie Harris, UCSF, (415) 885-7277; fax (415) 885-7393. Editorial: Lori Garvey, NSABP, (412) 330-4621; fax (412) 330-4661.
Note: This memo to reporters is from the Journal staff and is not an official release of the National Cancer Institute (NCI) or Oxford University Press (OUP) nor does it reflect NCI or OUP policy. In addition, unless otherwise stated, all articles and items published in the Journal reflect the individual views of the authors and not necessarily the official points of view held by NCI, any other component of the U.S. government, OUP, or the organizations with which the authors are affiliated. Neither NCI nor any other component of the U.S. government nor OUP assumes any responsibility for the completeness of the articles or other items or the accuracy of the conclusions reached therein.
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