Risk stratification in ductal carcinoma in situ: the role of genomic testing

From the earliest days of conservative surgery for ductal carcinoma in situ (DCIS) of the breast, there have been attempts to identify patients who may not need postoperative radiation. Randomized prospective trials have not identified a population for whom there is no benefit to radiation. However, decades of studies of clinical, radiological and pathologic correlates to local recurrence have led to criteria for a patient subgroup at low risk for local recurrence after omission of radiation. Gene expression profiling for invasive breast cancer has been used to identify patients at low, intermediate or high risk for distant recurrence. Application of this methodology to DCIS aims to identify patients at low, intermediate or high risk for local recurrence. Whether this method of risk stratification will prove more accurate than clinical, radiological and pathologic risk stratification, or identify patients with little to no clinical benefit from radiation, remains to be seen.