Accuracy of Diagnostic Biopsy for Cutaneous Melanoma: Implications for Surgical Oncologists

Abstract

Background and Objectives. While excisional biopsy is recommended to diagnose cutaneous melanoma, various biopsy techniques are used in practice. We undertook this study to identify how frequently final tumor stage and treatment recommendations changed from diagnostic biopsy to final histopathology after wide local excision (WLE). Methods. We compared the histopathology of the dermatopathologist-reviewed diagnostic biopsy and final WLE in 332 cutaneous melanoma patients. Results. Tumor sites were extremity (51%), trunk (33%), and head/neck (16%). Initial biopsy types were excisional (56%), punch (21%), shave (18%), and incisional (5%). Most diagnostic biopsies were margin positive regardless of technique, and 36% of patients had residual melanoma on WLE. T-stage changed in 8% of patients, of whom 59% were diagnosed by punch biopsy, 15% by incisional biopsy, 15% by shave biopsy, and 11% by excisional biopsy (P < 0.0001). Treatment recommendations changed in 6%: 2% after excisional biopsy, 5% after shave biopsy, 18% after punch biopsy, and 18% after incisional biopsy (P < 0.0001). Conclusions. Although most biopsy margins were positive, T-stage and treatment changed for only a minority of melanoma patients. Our data provide valuable information to inform patient discussion regarding the likelihood of a change in prognosis and the need for secondary procedures after WLE. These data support the superiority of dermatopathologist-reviewed excisional biopsy when feasible.

The effect of the AJCC 7th edition change in T1 melanoma substaging on national utilization and outcomes of sentinel lymph node biopsy for thin melanoma

“…Whereas multiple studies have reported that primary melanoma mitoses predict SLN status [12,13,19], others have reported no such association, with up to one-third of SLN-positive T1 melanomas having zero mitoses [15,16,20]. A positive deep biopsy margin may be associated with a higher likelihood of nodal metastasis for T1 melanoma patients with no otherwise discernible indication for SLNB (8.3% in one series), but it was recently dropped from National Comprehensive Cancer Network guidelines as an indication for consideration of SLNB [21,22]. Ulceration, which continues to classify thin melanomas as T1b, also has been reported as a factor that is variably associated with nodal status, but is a rare finding (1-15%) in thin melanomas [16].…”

Think before you shave: Factors influencing choice of biopsy technique for invasive melanoma and effect on definitive management

“…Bolshinky and colleagues showed following apparently complete excisional biopsy, 3.6% of WLEs had residual melanoma with a third of these cases requiring a second (three‐stage) or third (four‐stage) excision . Other studies have found similar, 2% rates of additional surgery following excisional biopsy and 2–5% rates of additional surgery following shave biopsy …”

Diagnosing melanoma: the method matters

“…Melanoma base transection is common in shave biopsies, the incidence ranging from 9% to 68% . Breslow tumour thickness (vertical depth of invasion) is the single most important prognostic characteristic of the primary tumour; it guides determination of the definitive resection margins and informs decisions about the appropriateness of sentinel lymph node biopsy (SLNB).…”