Melanoma: An FP’s guide to diagnosis and management
This review details the latest recommendations on dermoscopy and excision techniques, indications for sentinel lymph node biopsy, and Tx options.
PRACTICE RECOMMENDATIONS
› Consider adding dermoscopy to the physical exam to increase sensitivity and specificity in diagnosing melanoma. A
› Perform wide local excision for invasive cutaneous melanoma: 1-cm margin for tumors up to 1 mm thick; 1 to 2 cm for tumors > 1 mm to 2 mm thick; and 2 cm for tumors > 2 mm thick. A
› Do not hesitate to consider, as needed, hormone replacement therapy or hormonal contraception for women with a prior diagnosis of melanoma, as this form of contraception does not confer an increased risk of melanoma. B
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Wide excision and sentinel node biopsy
Wide excision of a primary melanoma is standard practice, with evidence favoring the following surgical margins: 0.5 to 1 cm for melanoma in situ, 1 cm for tumors up to 1 mm in thickness, 1 to 2 cm for tumors > 1 to 2 mm thick, and 2 cm for tumors > 2 mm thick.18 WE is often performed by dermatologists for nonulcerated tumors < 0.8 mm thick (T1a) without adverse features. If trained in cutaneous surgery, you can also choose to excise these thin melanomas in your office. Otherwise refer all patients with biopsy-proven melanoma to dermatologists to perform an adequate WE.
Refer patients who have tumors ≥ 0.8 mm thick to the appropriate surgical specialty (surgical oncology, if available) for consultation on sentinel lymph node biopsy. SLNB, when indicated, should be performed prior to WE of the primary tumor, and whenever possible in the same surgical setting, to maximize lymphatic drainage mapping techniques.18 Medical oncology referral, if needed, is usually made after WE.
SLNB remains the standard for lymph node staging. It is controversial mainly in its use for very thin or very thick lesions. Randomized controlled trials, including the Multicenter Selective Lymphadenectomy Trial,24 have shown no difference in melanoma-specific survival for patients with intermediate-thickness melanomas who had undergone SLNB.24
Many professional organizations consider SLNB to be the most significant prognostic indicator of disease recurrence. With a negative SLNB result, the risk of regional node recurrence is 5% or lower.18,25 In addition, sentinel lymph node status is a critical determinant for systemic adjuvant therapy consideration and clinical trial eligibility. For patients who have primary cutaneous melanoma without clinical lymphadenopathy, an online tool is available for patients to use with their physician in predicting the likelihood of SLNB positivity.26
Recommendations for SLNB, supported by multidisciplinary consensus:18
- Do not pursue SLNB for melanoma in situ or most cutaneous melanomas < 0.8 mm without ulceration (T1a). (See TABLE 127)
- Discuss SLNB with patients who have T1a melanoma and additional adverse features: young age, high mitotic rate, lymphovascular invasion, and nevus depth close to 0.8 mm with positive deep biopsy margins.
- Discuss SLNB with patients who have T1b disease (< 0.8 mm with ulceration, or 0.8-1 mm), although rates of SLNB positivity are low.
- Offer SLNB to patients with T2a and higher disease (> 1 mm).18
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