Mammography Screening Important After Lumpectomy for DCIS

Surveillance mammography after breast-conserving surgery for ductal carcinoma in situ (DCIS) appears to decline over time, despite the increased risk of invasive cancer, according to the results of a study published in the Journal of Clinical Oncology.[1]

Ductal carcinoma in situ is the earliest stage of breast cancer, during which the cancer is small and confined to an area within a duct of the breast. Previously, DCIS was often considered a “pre-cancerous” condition that had the potential to turn into cancer. Now, however, DCIS is largely accepted as an early stage of breast cancer and is treated accordingly, often with breast-conserving surgery.

DCIS is considered a precursor to invasive breast cancer, so it is important for women to continue to be screened with mammography for either recurrence of DCIS or newly diagnosed invasive breast cancer. Approximately 20% of women with DCIS will have a recurrence within five years, with almost half of those recurrences being classified as invasive breast cancer. Furthermore, these women are two to four times as likely to develop cancer in the opposite breast. Despite the increased risks, it is unclear whether women in this population continue to be vigilant about screening.

Researchers reviewed the medical records of 2,676 women diagnosed with DCIS between 1990 and 2001 and treated with breast-conserving surgery. They found that women were more likely to undergo surveillance mammography during the first year of follow-up—79% of the women had at least one mammography during this period. However, surveillance declined from there—at five years, 69% of women underwent surveillance and at 10 years, 61% were screened.

Surveillance mammograms were more likely among women age 60 to 69, women who used hormone therapy, and those treated with radiation and/or tamoxifen (Nolvadex®). Obese women were less likely to undergo surveillance mammography. Among the women observed for five years, only 34% of women had a surveillance mammogram during every year of follow-up, and of those observed for 10 years, only 15% underwent yearly mammograms.

The researchers concluded that despite the known increased risk of invasive cancer, surveillance mammography declined over time among women treated with breast-conserving surgery for DCIS. They recommend stronger monitoring efforts to ensure that women in this high-risk population are being adequately screened.

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