Active surveillance could be a viable alternative to surgery and radiation for select patients with ductal carcinoma in situ (DCIS) according to a mathematical model published in the Journal of the National Cancer Institute (doi:10.1093/jnci/djv263). The watch-and-wait approach may be most appropriate for older women and those with serious comorbidities.
Accurate staging at diagnosis would markedly improve any active surveillance approach for DCIS, noted the researchers who developed the model, who are based at Duke University in Durham, North Carolina.
“We currently lack the ability to determine whether the clusters of cells diagnosed as DCIS will remain harmless or progress,” said E. Shelley Hwang, MD, chief of breast surgery at Duke Cancer Institute, and senior author of the study. “As a result, we treat them all upon diagnosis as if they are invasive cancer, using a combination of surgery, radiation, and hormonal therapy.
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“There is growing concern that we may be causing harm by using aggressive procedures for some conditions that may never cause illness or death,” Hwang said. “Our study was designed to provide some guidance for an alternative approach.”
DCIS is diagnosed in more than 50,000 women a year in the United States. The disease is considered the earliest form of breast cancer, and 97% of women with DCIS undergo aggressive treatment. How many of those cases would have progressed to invasive cancer without treatment is not known; estimates are 20% to 50%.
Clinical trials in which women with DCIS are randomly assigned to either current treatment or active surveillance are lacking. The Duke team set to building a mathematical model to determine when active surveillance might be a viable alternative, using data from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program.
Hwang and colleagues, including mathematicians and biostatisticians, created a risk projection model for mortality from all causes among women in different age groups: 39 to 41 years, 54 to 56 years, and 69 to 71 years.
Using the projection model, the researchers evaluated how active surveillance would compare to usual treatment as a risk for death, relying on current estimates of disease progression, screening accuracy, and other variables.
Active surveillance for DCIS did not increase risk of death for women age 69 to 71 years compared with current treatment regimens for DCIS, and it was nearly 6 times less lethal than other competing health conditions in this age group. As a result, active surveillance could be especially beneficial to older women who have serious comorbidities such as heart disease.
For younger women (age 39 to 41 years), active surveillance poses a substantial risk over usual care. Women age 54 to 56 years were found to have a slightly elevated risk of breast cancer death with an active surveillance compared with usual care, but the approach posed no greater risk than other potential causes of death.
