Re-excision Unnecessary in Mild to Moderate Atypical Nevi

Jim Kling

April 02, 2014

DENVER — Re-excision of atypical nevi with microscopic margins on initial biopsy, currently a fairly common practice, might be unnecessary in mild or moderate cases, according to a retrospective analysis.

"There's no consensus on what management of atypical nevi should be," said Michael Cashman, MD, a dermatology resident at Medstar Washington Hospital Center, Georgetown University Hospital, Washington, DC.

"There should be practice guidelines, but we can't establish guidelines unless there's evidence-based research," he told Medscape Medical News.

Dr. Cashman presented results from the analysis here at the American Academy of Dermatology 72nd Annual Meeting.

To investigate atypical nevi outcomes, he and his team conducted a retrospective review of cases at their pigmentation specialty clinic over a 9-year period. Of the 2936 consecutive biopsies evaluated, 871 revealed atypia.

A decision was made to re-excise 167 of the 871 nevi. Of these, 129 showed scarring with no evidence of residual atypical nevus. Of the remaining 38, 14 were had residuum without atypia and 24 had atypical residuum. Severity was discordant in 11 of the 24 cases of atypical residuum (7 were downgraded, 4 were upgraded). No instances of melanoma were found in any of the re-excisions.

Overall, 85% of re-excisions showed no sign of residual atypical nevus. On subgroup analysis of patients with moderate and severe atypia plus margin status, this percentage was reproducible (range, 81% - 93%).

The 130 subjects who did not undergo re-excision were monitored closely for a median of 12 months. None of them developed melanoma during that follow-up period.

Dr. Cashman noted that the clinic where this study was conducted tends to do saucerizations to remove the entire mole at biopsy.

"There's a trend moving toward deeper saucerization biopsy," he explained. "That has caught on a little faster than the concept that we might not need to re-excise moderately atypical moles. We know that deeper saucerization biopsy removes more tissue upfront and raises the likelihood of obtaining clear margins on initial biopsy."

Because many dermatologists base their re-excision decision on margin status, "I believe it does directly affect the need to re-excise," he added.

As for the impact that this study will have on clinical practice, Dr. Cashman said he isn't prepared to make a blanket recommendation.

"I don't think I can make a hard and fast rule that moderate atypical moles do not need to be excised. It depends on the patient. If they only have 1 moderately atypical mole, then you could probably follow it instead of doing a re-excision. If they have multiple irregular moles and a history of atypical nevi, then I would be a little more cautious and do the excision. As we continue to do more research to elucidate the biologic behavior of moles, we should be able to come up with reasonable clinical guidelines," he said.

The study is informative, said Delphine Lee, MD, director of the Department of Translational Immunology at the John Wayne Cancer Institute, Saint John's Health Center, in Santa Monica, California.

"It's good to have hard data and hard numbers to inform re-excision decisions," she told Medscape Medical News, pointing out that if some procedures aren't necessary, it could save money and resources.

Still, it might make physicians nervous to forego the re-excision of atypical nevi, on the chance that the patient will be the one who will go on to develop melanoma, no matter how low the odds.

"That's what you worry about. It's kind of a controversial thing," said Dr. Lee.

Dr. Cashman and Dr. Lee have disclosed no relevant financial relationships.

American Academy of Dermatology (AAD) 72nd Annual Meeting. Presented March 22, 2014.

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