ORLANDO – Re-excisions are not needed when clinically excised moderately dysplastic nevi have positive histologic margins, based on results of a retrospective study of 438 patients who were treated at nine academic medical centers in the United States.
Not a single patient in the study developed melanoma at the excision site after an average follow-up of 6.9 years, and at least 3 years in all cases, saidMD, of Emory University, Atlanta, and Atlanta Veterans Administration Medical Center, one of the study investigators.
The finding “really has the potential to change how we manage these lesions. You don’t need to cut [these patients] again. You can watch them. Close observation with routine skin surveillance is reasonable,” Dr. Berry said at the International Investigative Dermatology meeting.
Routine skin exams are essential for patients with a history of dysplastic nevi as these patients are at risk for developing melanoma. Indeed, in this study, 100 patients (22.8%) subsequently developed melanomas at a site other than the location of their biopsy.
The study included 438 patients who had 467 biopsies that indicated incomplete excision of a moderately dysplastic nevus from 1990 to 2014. Patients were at least 18 years old and were an average of 47 years old. About half had a history of dysplastic nevi, and a third had a history of melanoma.
All of their biopsies for moderately dysplastic nevi had positive margins, but patients had no clinically apparent residual pigment at their excision sites. Lesions were equally as likely to be removed by shave and punch biopsies, and the majority of the nevi were located on the trunk. Complete excision was the intent in all cases.
To control for interobserver variability, the centers submitted a total of 40 slides for central dermatopathology review, which found agreement in 35 cases (87.8%). Two of the remaining five cases were downgraded to mild dysplasia, two were upgraded to severe, and one patient was upgraded to melanoma in situ, but hasn’t had a recurrence after 5 years of follow-up.
Controlling for age, sex, and family history, a patient history of dysplastic nevus prior to the biopsy doubled the risk of a subsequent melanoma (P = .017), and a history of melanoma increased it almost eightfold (P less than .001).
Knowing these risk factors, patients with a history of dysplastic nevi “need to have more frequent total body skin exams. What that frequency is, we don’t know,” Dr. Berry said.
The investigators reported they had no relevant disclosures.
SOURCE: Kim CC et al. IID 2018, .