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Karl D. Lewis, MD


ASCO 2022: Pan-Canadian Merkel Cell Collaborative Provides Insight on Biopsy Decisions

By: Celeste L. Dixon
Posted: Friday, June 17, 2022

Recently presented evidence seems to tilt the scale in favor of sentinel lymph node biopsy in cases of clinically node-negative Merkel cell carcinoma, although authors of the study acknowledge the topic is controversial. The record review performed by Megan E. Delisle, MD, MSc, MPH, of the University of Ottawa, Ontario, and colleagues was presented during the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 9583). It included 750 patients who were treated at 13 Canadian medical centers for Merkel cell carcinoma from 2000 to 2018.

Of the 485 patients who had clinically node-negative disease at presentation, 290 patients did not undergo sentinel lymph node biopsy and 195 did. Of the 177 patients for whom the biopsy results were available, 60 (33.9%) tested positive. After a median follow-up of 2.7 years, sentinel lymph node biopsy (vs. no biopsy) was found to be “associated with a reduced risk of regional recurrence (P = .01) and improved overall survival (P < .01),” the investigators wrote.

The study results pivoted on what happened to the 60 patients after the positive results were received: They underwent completion dissection and nodal radiation (n = 22), nodal radiation alone (n = 18), completion dissection alone (n = 15), or observation (n = 5). Those who had no sentinel lymph node biopsy underwent observation (86.2%) or nodal radiation alone (13.8%).

The regional recurrence rate was 14.5% versus 15% in the patients who had negative versus positive sentinel lymph node biopsy results, reported the authors, and 15% in the patients who had no sentinel lymph node biopsy but received nodal radiation. However, among those patients who had no biopsy, followed by observation, the regional recurrence rate was 25.2%. Dr. Delisle and co-investigators noted that no significant differences in local recurrence, distant recurrence, or cancer-specific survival were seen between the patients who did or did not undergo sentinel lymph node biopsy.

Disclosure: Full disclosures of the study authors can be found at

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