This new analysis of the Oncotype DX DCIS assay strengthens the findings of earlier studies performed in more limited subgroups.
—Benjamin O. Anderson, MD
Commenting on this study, Benjamin O. Anderson, MD, Director of the Breast Health Clinic, Seattle Cancer Care Alliance, Washington, said: “This new analysis of the Oncotype DX DCIS assay strengthens the findings of earlier studies performed in more limited subgroups, validating that the assay accurately segregates lower- from intermediate- and high-recurrence risk subgroups of patients treated with complete surgical excision without radiotherapy. In this Canadian cohort, low-score patients treated by complete surgical excision alone had a recurrence rate of 12.7% at 10 years.”
Dr. Anderson pointed out that the assay does not directly assess the efficacy of radiation therapy for ductal carcinoma in situ, since no patients in this cohort were radiated. “However, for patients who prefer to undergo lumpectomy alone for ductal carcinoma in situ and thereby avoid radiation treatment, the assay may provide reassurance for their choice if they feel reasonably comfortable with an 8% risk of developing invasive breast cancers at 10 years,” he stated.
Confusion Over DCIS
“People get confused about ductal carcinoma in situ. It is not a cancer by strict definition but a precancerous lesion because it has not yet spread outside the milk duct and does not spread to other parts of the body at that early stage,” said C. Kent Osborne, MD, Director of the Dan L. Duncan Cancer Center at Baylor College of Medicine in Houston. “There have been many discussions about this, and some people want to remove the word ‘cancer’ from the classification. This study is one of the first steps we need to take to start backing off of treating patients at low risk of tumor recurrence. The next step is to integrate the DCIS Score with known risk factors such as age and family history,” he added. Dr. Osborne moderated a press conference where these data were discussed.
He said that it is a “no-brainer” that the test would be reimbursed, because it can save money by not overtreating low-risk patients. “The assay only provides estimates of risk of tumor recurrence, but it gives no data on outcomes if patients are treated according to their risk level,” he noted. ■
Disclosure: Drs. Anderson and Osborne reported no potential conflicts of interst.
Ductal carcinoma in situ, which accounts for 30% of all newly diagnosed breast cancers, does not always evolve into a lesion with metastatic potential. Only a proportion of these cases will progress to invasive breast cancer, but up until recently, it has not been possible to identify reliably...