Women with ductal carcinoma in situ (DCIS) who are treated with breast-conserving surgery are sometimes also subjected to an extra procedure, a sentinel lymph node biopsy (SLNB), even though this extra step offers no benefits but may cause harm.
A new study conducted in older women with DCIS found that 15% of women underwent this extra procedure and that it had no long-term benefits. The study was funded by the Patient-Centered Outcomes Research Institute.
"People tend to think that more is better, but more is not better, it's just more," said Laura Esserman, MD, MBA, director of the University of California, San Francisco, Carol Franc Buck Breast Care Center, who was not involved in the study. "In this case, more is worse, because you get side effects without benefits."
The new study was published online October 23 in JNCI Cancer Spectrum and was highlighted at a press briefing organized by the National Center for Health Research.
This is the first study to examine the long-term impact of SLNB for patients with DCIS, commented lead study author Shi-Yi Wang, MD, PhD, of the Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale Cancer Center in New Haven, Connecticut. Wang has received research support from Genentech.
"Our study found that SLNB has no long-term benefits for older women with DCIS," Wang said. Given the increased risk for side effects, including lymphedema, "SLNB should be avoided," he concluded.
Indeed, guidelines from the American Society of Clinical Oncology and the National Comprehensive Cancer Network do not recommend SLNB for women with DCIS who have breast-conserving surgery.
For their study, Wang and colleagues identified records of 1992 women with DCIS in the Surveillance, Epidemiology, and End Results (SEER)–Medicare database who underwent SLNB and matched them with records from 3965 women with DCIS who did not undergo SLNB and who served as controls for the study.
All of the women were aged 67 to 94 years, were diagnosed with DCIS between 2001 and 2013, and received breast-conserving surgery in the first 6 months after diagnosis but did not undergo mastectomy within 9 months.
The 1992 women who underwent SLNB represented 15.6% of the total 12776 women with DCIS in the SEER-Medicare database treated with breast-conserving surgery.
The team found that there were no statistically significant differences between patients who underwent SLNB and those who didn't with regard to rates of subsequent mastectomy (3.9% vs 3.7%), occurrence of ipsilateral invasive breast cancer (1.4% vs 1.7%), or breast cancer mortality (1.0% vs 0.9%). Median follow-up time was 69 months.
Speaking at the press briefing, Esserman said she was "shocked" that 15% of the women in the study underwent SLNB, given their demographics. "An alarming trend is that more people are getting SLNB in this older population where there is clearly no value," she said.
The study was retrospective and observational and could not control for potential confounding factors, including obesity, endocrine therapy status, postsurgical margin status, presence of a mass lesion, and provider's treatment preference, Wang and coauthors write. They also note a need for further research on SLNB in treating DCIS with high-risk features and that the results may not be generalizable for younger women.
A large, randomized controlled trial that tests whether SLNB is beneficial for DCIS patients would be difficult to conduct. For this reason, "this may be the best evidence we get to answer this question," commented J. Leonard Lichtenfeld, MD, deputy chief medical officer of the American Cancer Society, who was approached for comment.
"The evidence is reasonable in this study to suggest in older women with more typical DCIS, doing SLNB for the sake of doing that biopsy did not make a difference in the outcome for that particular woman," he told Medscape Medical News.
"Lot of things in medicine are done because we think they work," Lichtenfeld said. "Now, there are experts asking important questions: Do they really make a difference? Do we have to do them?"
JNCI Cancer Spectr. Published online October 23, 2019. Full text
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Cite this: In Older Women With DCIS, Skip Lymph Node Biopsy - Medscape - Oct 24, 2019.