New Prognostic Tool to Guide Treatment of Ductal Carcinoma In Situ
San Antonio, TX—The treatment of ductal carcinoma in situ (DCIS)— breast cancer confined to the ducts—is a clinical challenge, as patients carry varying risks of recurrence and may easily be undertreated or overtreated. But Genomic Health, which markets Oncotype DX for assessing risk of recurrence in invasive cancers, has developed a similar test for DCIS that may prove useful for individualizing treatment in this subset of breast cancer. The test is expected to become available for physicians for use on December 28, 2011.
“DCIS is a very common presentation, and due to screening mammog – raphy, its incidence is rising. Most patients can undergo breast-conservation surgery, but the question is whether patients with a diagnosis of DCIS require invasive therapy, especially radiation,” said Lawrence J. Solin, MD, Chair of Radiation Oncology, Albert Einstein Medical Center, Philadelphia. “We have developed a prognostic tool for these patients.”
Using a subset of genes from the Oncotype DX Recurrence Score, Dr Solin and colleagues calculated a prespecified “DCIS score” (0-100) for these patients to predict recurrence, based on these risk categories: low risk (<39), intermediate risk (39-54), or high risk (≥55). They also prospectively validated the quantitative multigene reverse transcriptase polymer chain reaction assay and found the DCIS score reliable. The tumor gene expression information complements traditional clinical and pathologic factors, guiding oncologists in selecting patients with DCIS who should be treated with surgery alone or surgery plus radiation.
The validation study of the DCIS score was a collaboration among the Eastern Cooperative Oncology Group (ECOG), North Central Cancer Treat – ment Group, and Genomic Health, using samples from the ECOG E5194 study of patients with low-, intermediate-, or high-grade DCIS who had been treated surgically but had not received radiation. Tumors from these patients were tested to determine the risk of recurrence, and researchers applied the Oncotype DX assay and the new DCIS score algorithm to study the tumor samples.
DCIS Score Accurately Predicted Risk
The 10-year results of E5194, showing that 46 patients developed local recurrence of DCIS or an invasive cancer in the same breast, found the DCIS score to be significantly associated with these breast events and provided value beyond the traditional measures of tumor size, tumor grade, and margin status.
Patients with a high DCIS score had a 10-year risk for an ipsilateral breast event of 27.3%; intermediate-risk patients had a 24.5% risk, and low-risk patients had a 12.0% risk (P = .02), Dr Solin reported.
“DCIS score was a significantly strong predictor of local recurrence or invasive local recurrence. Fortun – ately, three quarters of patients were in the low-risk group,” he said. “We think the DCIS score provides a new clinical tool to guide treatment selection for patients with newly diagnosed DCIS.”
Jennifer Ligibel, MD, of Dana- Farber Cancer Center, Boston, who moderated a press briefing where the results were highlighted, commented, “This is very important work as we try to better tailor therapy for our patients.”
Dr Solin said he did not know what the test would cost, “but in a broader sense, you have to consider the total cost of care. If we can spare adjuvant therapies in some patients, it becomes very cost-effective.”