Physicians have a new resource for managing disease in patients with early-stage breast cancer. A multigene analyzer for ductal carcinoma in situ (DCIS) considers gene patterns to individualize therapy and determine the chance for recurrence, potentially sparing the patient additional therapy.
The DCIS Score, published in the Journal of the National Cancer Institute (2013; doi: 10.1093/jnci/djt133), shows that the expression of 12 genes can provide information in addition to age, personal history, tumor type, tumor size, and other factors to determine whether a woman’s risk for recurrence in the same breast is low, medium, or high. That score plays a significant role in the treatment options suggested by her physician.
“The DCIS Score will be a blessing to many women who, until now, had no scientific way to determine how much or how little treatment they needed to avoid the spread of their disease,” said Sunil Badve, MD, of Indiana University in Indianapolis. “The test results can give patients peace of mind, knowing that the conclusions about their risk for recurrence were made with genetic information obtained from their own tumor and therefore is specific to them.”
Researchers compared data from 327 patients with DCIS treated with surgical removal of the breast tumor but no radiation from an Eastern Cooperative Oncology Group study.
Factors considered in the development of the DCIS Score were age, menopause status, tumor size, margin width of the excision, tumor grade, and an analysis of 21 genes, including seven genes that predict recurrence risk. The DCIS Score breakdown is 1 to 39, low risk; 40 to 54, intermediate risk; and beyond 55, high risk.
Mastectomy was once the standard treatment for DCIS, and it has recurrence rates as low as 1.4%. For women with ductal carcinoma treated with breast-conserving therapy (lumpectomy), surgery alone cures 70%; however 30% of women may develop a recurrence in the same breast. The addition of radiation dramatically reduces the risk for recurrence by approximately 50%, making the risk about 15%. Some physicians recommend the addition of the drug tamoxifen, which blocks the estrogen receptor, further reducing the chance for recurrence to 8% to 10%.
The DCIS Score allows physicians to identify the patients in the high-risk group who need the full course of therapies. On the other hand, it also identifies a low-risk group in whom additional treatments with radiation and/or tamoxifen might be unnecessary.
“Giving radiation and drug therapy to 100% of all DCIS patients to prevent recurrences in a small percentage of patients is wrong,” Badve said. “Science can safeguard patients and protect them from unnecessary interventions.”