Surgery is the first choice therapy for localized cutaneous melanoma. Depending on the stage a sentinel lymph node biopsy is done as well, although controversy exists around trial evidence for this procedure. Treatment of advanced malignant melanoma is performed from a multidisciplinary approach.
Diagnostic punch or excisional biopsies may appear to excise (and in some cases may indeed actually remove) the tumor, but further surgery is often necessary to reduce the risk of recurrence.
Complete surgical excision with adequate margins and assessment for the presence of detectable metastatic disease along with short- and long-term followup is standard. Often this is done by a "wide local excision" (WLE) with 1 to 2 cm margins. Melanoma-in-situ and lentigo malignas are treated with narrower surgical margins, usually 0.2 to 0.5 cm. Many surgeons consider 0.5 cm the standard of care for standard excision of melanoma-in-situ, but 0.2 cm margin might be acceptable for margin controlled surgery (Mohs surgery, or the double bladed technique with margin control). The wide excision aims to reduce the rate of tumour recurrence at the site of the original lesion. This is a common pattern of treatment failure in melanoma. Considerable research has aimed to elucidate appropriate margins for excision with a general trend toward less aggressive treatment during the last decades.
Mohs surgery has been reported with cure rate as low as 77% and as high as 98% for melanoma-in-situ.
Melanomas which spread usually do so to the lymph nodes in the region of the tumor before spreading elsewhere. Attempts to improve survival by removing lymph nodes surgically (lymphadenectomy) were associated with many complications but unfortunately no overall survival benefit. Recently the technique of sentinel lymph node biopsy has been developed to reduce the complications of lymph node surgery while allowing assessment of the involvement of nodes with tumor.controversial and without prolonging survival, "sentinel lymph node" biopsy is often performed, especially for T1b/T2+ tumors, mucosal tumors, ocular melanoma and tumors of the limbs. A process called lymphoscintigraphy is performed in which a radioactive tracer is injected at the tumor site in order to localize the "sentinel node(s)". Further precision is provided using a blue tracer dye and surgery is performed to biopsy the node(s). Routine H&E staining, and immunoperoxidase staining will be adequate to rule out node involvement. PCR tests on nodes, usually performed to test for entry into clinical trials, now demonstrate that many patients with a negative SLN actually had a small number of positive cells in their nodes. Alternatively, a fine-needle aspiration may be performed and is often used to test masses.
If a lymph node is positive, depending on the extent of lymph node spread, a radical lymph node dissection will often be performed. If the disease is completely resected, the patient will be considered for adjuvant therapy.
High risk melanomas may require adjuvant treatment. In the United States most patients in otherwise good health will begin up to a year of high-dose interferon treatment, which has severe side effects but may improve the patient's prognosis. This claim is not supported by all research at this time, and in Europe interferon is usually not used outside the scope of clinical trials.
Metastatic melanomas can be detected by X-rays, CT scans, MRIs, PET and PET/CTs, ultrasound, LDH testing and photoacoustic detection.
Chemotherapy and immunotherapy
Various chemotherapy agents are used, including dacarbazine (also termed DTIC), immunotherapy (with interleukin-2 (IL-2) or interferon (IFN)) as well as local perfusion are used by different centers. They can occasionally show dramatic success, but the overall success in metastatic melanoma is quite limited. IL-2 (Proleukin) is the first new therapy approved for the treatment of metastatic melanoma in 20 years. Studies have demonstrated that IL-2 offers the possibility of a complete and long-lasting remission in this disease, although only in a small percentage of patients. A number of new agents and novel approaches are under evaluation and show
promise. Clinical trial participation should be considered the standard of care for metastatic melanoma.
In 2005, a phase III clinical trial for a melanoma vaccine was halted after showing little benefit compared to placebo. On June 23, 2008, Israeli scientists from the Oncology Institute of the Hadassa Medical Center in Jerusalem [http://www.israelnationalnews.com/News/Flash.aspx/148679 announced they developed a vaccine that prevents recurrences of the disease among previous sufferers and increases chances of survival for current ones. One of the most promising current experimental treatment approaches, also an immunotherapy, is OncoVEX GM-CSF (BioVex Inc, Woburn, MA) which is currently in Phase 3 clinical trials following a very high level of efficacy having been observed in Phase 2.
Lentigo maligna treatment
Standard excision is still being done by most surgeons. Unfortunately, the recurrence rate is exceeding high (up to 50%). This is due to the ill defined visible surgical margin, and the facial location of the lesions (often forcing the surgeon to use a narrow surgical margin). The narrow surgical margin used, combined with the limitation of the standard bread loafing technique of fixed tissue histology - result in a high "false negative" error rate, and frequent recurrences. Margin controlled (peripheral margins) is necessary to eliminate the false negative errors. If breadloafing is utilized, distances from sections should approach 0.1 mm to assure that the method approaches complete margin control.
Mohs surgery has been done with cure rate reported to be as low as 77%, The "double scalpel" peripheral margin controlled excision method approximates the Mohs method in margin control, but requires a pathologist intimately familiar with the complexity of managing the vertical margin on the thin peripheral sections and staining methods.
Some melanocytic nevi, and melanoma-in-situ (lentigo maligna) have resolved with an experimental treatment, imiquimod (Aldara) topical cream, an immune enhancing agent. Some dermasurgeons are combining the 2 methods: surgically excising the cancer and then treating the area with Aldara cream postoperatively for three months. Considering the very poor cure rate with standard excision, it might not be a bad idea to follow up all surgical excisions with topical imiquimod treatments.
Radiation and other therapies
Radiation therapy is often used after surgical resection for patients with locally or regionally advanced melanoma or for patients with unresectable distant metastases. It may reduce the rate of local recurrence but does not prolong survival.
In research setting other therapies, such as gene therapy, may be tested. Radioimmunotherapy of metastatic melanoma is currently under investigation.
Experimental treatment developed at the National Cancer Institute (NCI), part of the National Institutes of Health in the US was used in advanced (metastatic) melanoma with moderate success.
The treatment, adoptive transfer of genetically altered autologous lymphocytes,
depends on delivering genes that encode so called T cell receptors (TCRs), into patient's lymphocytes. After that manipulation lymphocytes recognize and bind to certain molecules found on the surface of melanoma cells and kill them.
A new treatment that trains the immune system to fight cancer has shown modest benefit in late-stage testing against melanoma.
This article is licensed under the Creative Commons Attribution-ShareAlike License.
It uses material from the Wikipedia article on
All material adapted used from Wikipedia is available under the terms of the
Creative Commons Attribution-ShareAlike License.
Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.