Study Findings Support Consideration of Second Biopsy for Transected Melanomas

M. Alexander Otto

June 03, 2021

Almost 14% of transected invasive melanoma biopsies at the University of Alabama at Birmingham were up-staged on final surgical pathology, in a review of cases at the university.

Had their true Breslow depths been known before definitive surgery, sentinel lymph node (SLN) biopsies and wider surgical margins would likely have been recommended.

The findings led the investigators to conclude that a second biopsy should be considered when the first one is transected to ensure surgical and other management decisions are based on an accurate Breslow depth.

A second biopsy is especially warranted for broadly transected biopsies and transected T1a tumors with gross residual tumor or pigment on preoperative exam; both scenarios significantly increased the risk of up-staging in the study, according to lead investigator James Duncan, MD, a Mohs surgery and dermatologic oncology fellow at the University of Alabama at Birmingham, who presented the findings at the annual meeting of the American College of Mohs Surgery.

"Accurate staging of malignancies, especially melanoma, is critical to determine prognosis and the best treatment approach," said Vishal Patel, MD, director of cutaneous oncology at George Washington University, Washington, DC, when asked for comment.

"This study identifies how transected biopsies can underestimate a melanoma's true depth and thus impact treatment and outcomes. The authors highlight that when a biopsy is transected, or there is notable pigment at the base, attempts should be taken to sample the remaining tumor prior to surgery so the accurate tumor depth can be determined and treatment options be fully discussed with the patient," Patel said.

The Birmingham team reviewed invasive melanoma cases at their university from 2017 to 2019.

Almost half (49.6%) of the 726 melanomas they identified were transected on biopsy, which is in line with prior reports. About 60% of the patients were men and 98% were white; the average age was 63 years.

Of the 360 transected tumors, 49 (13.6%) had up-staging at final excision that "would have prompted discussion of alternate surgical treatment such as SLN biopsy or wider surgical margins," the team said.

Of the 89 transected pT1a melanomas identified, 47.1% with gross residual tumor or pigment on preoperative physical examination were up-staged following excision versus 6.9% with no remaining pigment or tumor prior to surgery (P < .01).

Broadly transected tumors were up-staged in 21.7% of cases vs 4.9% of focally transected tumors (P = .038). The average increase in Breslow depth for broadly transected tumors was 1.03 mm vs 0.03 mm for focally transected lesions (P = .04).

Shave biopsies, ulceration, and lack of concern for melanoma at the initial biopsy were among the factors associated with a higher risk of transection.

Superficial spreading melanoma was the most common subtype. Tumors were evenly distributed between the head, neck, and extremities. The average Breslow depth was 1.51 mm, and the majority of tumors were pT1a or pT2a.

The review excluded melanoma in situ, recurrences, metastases, noncutaneous melanomas, and biopsies where deep margin status was unknown.

There was no funding for the study, and Duncan and Patel had no relevant disclosures.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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