Cutaneous melanoma is diagnosed in over 80,000 people in the US every year. While it represents just four percent of skin cancers, it accounts for over 80 percent of the skin cancer deaths. Melanomas continue to be diagnosed at an alarming rate. Increased awareness by both the public and physicians account in large part for the increase, though relative numbers continue to climb.
T1 tumors are generally treated by generous excision, though sometimes this surgery alone can be challenging in awkward or cosmetically sensitive areas. Sometimes skin grafts or local tissue rearrangement may be necessary. Unfortunately, surgical margins for resections of melanoma cannot be checked by frozen section because the technique is unreliable for differentiating normal from malignant melanocytes. Frequently it is better to do the primary resection, cover the wound with a dressing and wait 3 days for permanent section before closure.
T2 tumors with Breslow thicknesses of 1.0 or greater generally require sentinel node biopsy. If the sentinel node is positive, protocol recommends completion lymphadenectomy. It is well-established that excision of the sentinel node does not improve survival and neither does regional lymphadenectomy. Sentinel node biopsy is not a treatment but a diagnostic test that may help determine further medical therapy. In patients who undergo completion lymphadenectomy, only 20 percent have additional positive non-sentinel lymph nodes and those are in patients who have generally deep tumors. In patients with only a small microscopic subcapsular metastasis, the percentage is even less. Morbidity with regional lymphadenectomy is always of concern. Some clinical trials are evaluating observation with serial ultrasound of the nodal basins in selected patients with a positive sentinel node. Like patients with breast cancer today, there is a tendency to do less surgery. Many other factors also come into play with evaluation of outcomes. For example, younger patients have a higher incidence of positive sentinel node than older patients with similar tumors, but their survival is better than those in older patients with a negative node.
Like many other cancers, melanoma is now being assessed by gene expression profile. For example, Castle Biosciences (in Houston, TX and Phoenix, AZ) has developed a proprietary 31 gene assay that uses RT-PCR to assess the metastatic potential of tumors that are sentinel node negative. The test stratifies the patients to Class A, low risk of metastasis or Class 2, high risk of metastasis. The low risk patients have a 97 percent chance of being metastasis free for 5 years, while Class 2 patients have only a 31 percent chance. Hopefully those patients with high risk can be selected for increased surveillance and possibly more aggressive treatment.
Like breast cancer, melanoma is now not just a surgical disease but a medical management issue as well. Two approaches have proven beneficial, including immunomodulation and targeted molecular therapy toward mutations found in melanocytic lesions. For example, BRAF mutations are found in approximately 50 percent of melanomas, and in appropriate situations can be treated with BRAF inhibitors. In the last several years, the US Food and Drug Administration has approved 6 immunomodulator therapies for melanoma. Many patients have had significant remissions and some quite prolonged. Like most cancers, the best treatment is early recognition and public awareness.
Dr. Lawrence Cervino is board-certified in Plastic Surgery and Surgery and specializes in melanoma, head and neck reconstruction, and cosmetic surgery. He is the founder of Crystal Plastic Surgeons and sees patients in the Akron and Medina offices.