Less aggressive DCIS treatment increases risk for recurrence
Inadequate excision of ductal carcinoma in situ leads to recurrence or development of invasive disease in more than half of women by 10 years, according to results of a prospective database analysis presented at the American Society of Breast Surgeons Annual Meeting.
Whether ductal carcinoma in situ (DCIS) is overtreated with standard therapy has been debated.
“The DCIS controversy has been distorted in the media and many women are confused,” Sadia Khan, DO, program advisor of Hoag Breast Care Center and assistant clinical professor of surgery at Keck School of Medicine at University of Southern California, said in a press release.
“The [previous] studies themselves are valid, but much more research is needed before medical science, let alone the media, draws any hard and fast conclusions.”
Khan and colleagues reviewed database records from 720 patients (mean age, 55 years; mean tumor size, 17 mm) with DCIS and no invasion or microinvasion who were treated with excision alone.
Researchers divided patients into two groups based on margin size: those with margins less than 1 mm (n = 124) and those with a margin greater than or equal to 1 mm (n = 596). Patients with margins less than 1 mm were considered inadequately excised and advised to undergo re-excision but all refused additional treatment.
In the cohort of women with margins less than 1 mm, 69 women had nuclear grade I and II disease — considered low grade — and 55 had nuclear grade III disease, considered high grade. In the cohort with margins of 1 mm or greater, 406 had nuclear grade I or II disease and 190 had nuclear grade III disease.
The primary study measure was RFS.
“Unlike many recent DCIS studies, we focused on recurrence, not mortality as an endpoint,” Khan said. “With DCIS ... recurrence may lead to a more advanced form of breast disease, and potentially more aggressive treatment at a later date.”
Mean follow-up was 79 months.
Five-year and 10-year RFS significantly differed between patients with low-grade and high grade DCIS, and for patients with margins less than 1 mm and greater than or equal to 1 mm (P < .001).
Researchers then evaluated 5- and 10-year RFS outcomes of women within each nuclear grade according to whether they were adequately or inadequately excised.
Patients with low-grade DCIS who were inadequately excised had a higher rate of recurrence than women with wider margins at 5 years (18% vs. 8%) and 10 years (53% vs. 13%). Patients with high-grade DCIS who were inadequately excised also had a higher rate of recurrence than women with adequate excision at 5 years (55% vs. 23%) and 10 years (67% vs. 36%; P < .001 for all).
“This study clearly shows that excising DCIS with a minimum of 1-mm margin of disease-free tissue is beneficial for many women and that further study is needed before current protocols are revised,” Khan said. “Women frequently come into our practice and say they have read that DCIS does not require treatment. Clearly our study suggests this is untrue.” – by Nick Andrews
Khan S, et al. Are we over-treating ductal carcinoma in situ (DCIS)? Presented at: American Society of Breast Surgeons Annual Meeting; April 13-17, 2016; Dallas, Texas.
Disclosure : HemOnc Today could not confirm the researchers’ relevant financial disclosures at the time of reporting.