Study: Half of Undertreated DCIS Patients Recur Within a Decade

More than half of women under- or inadequately treated for their ductal carcinoma in situ (DCIS) may develop a recurrence of the disease or invasive breast cancer within 10 years, according to a study presented at the 2016 American Society of Breast Surgeons Annual Meeting, held April 13–17 in Dallas, Texas.

The study, according to researchers led by Sadia Khan, DO, of the Keck School of Medicine at the University of Southern California, points to a need to evaluate appropriate DCIS treatment options for individual patients and for the public to understand that more research is needed to know whether surveillance is the best option for most women diagnosed with DCIS.

The researchers analyzed prospective data on 720 DCIS patients treated with excision alone who had no documented invasion or microinvasion and analyzed local recurrence rates of DCIS or invasive disease. Patients were divided into those with “inadequate” excision margins of less than 1 mm and those with margins of 1 mm or greater. Patients were further subcategorized by grade of DCIS.

Among patients treated with inadequate excision margins (less than 1 mm), in those with low-grade DCIS (n = 69) the 5- and 10-year local recurrence rates were 18% and 53%, respectively; in those with high-grade DCIS (n = 55) the 5- and 10-year rates were 55% and 67%.

In this patient group (margins of less than 1 mm), no patient developed distant recurrence or died of their disease.

Among patients treated with excision margins of 1 mm or greater, in those with low-grade DCIS (n = 406) the 5- and 10-year local recurrence rates were 8% and 13%, respectively; in those with high-grade DCIS (n = 190) the 5- and 10-year rates were 23% and 46%.

In this patient group (margins of 1 mm or greater), two patients with low-grade DCIS developed distant recurrence and one died of their disease; one patient with high-grade disease developed a distant recurrence.

“With DCIS, we knew mortality would be low. However, recurrence may lead to a more advanced form of breast disease, and potentially more aggressive treatment at a later date,” said Khan in a statement. “For example, treatment for invasive breast cancer recurrence might include lymph node dissection, extensive radiation, or mastectomy, which could significantly lower a woman’s quality of life going forward.”

The results, according to Khan, point to a need to better understand DCIS recurrence. Because of the relatively high invasive recurrence rates, simple surveillance may not be the best option for some women, the study authors concluded.