Primary melanoma is always removed by surgery, with enough normal skin from around the melanoma to make sure all the cancer cells have been removed (this is referred to as the safety margin). The margin removed depends on the thickness of the melanoma, anywhere between 5mm and 3cm.
Localised metastatic melanoma is best treated by surgical excision as well. Metastatic disease that spreads to distant skin sites and lymph nodesis usually able to be treated in this manner, and even spread to internal organs can sometimes be removed successfully with surgical intervention.
Sentinel Node Biopsy
A new technique to see if the melanoma has spread to the lymph nodes closest to the melanoma is called “sentinel node biopsy”. A substance containing a small amount of radioactivity is injected into the skin around the tumour. The substance passes into the lymph fluid and is trapped by the sentinel node. That lymph node can be removed and examined to see if there are any cancer cells in it. This technique is only used for thicker melanomas.
Examination of the “sentinel” lymph node or nodes in a patient with a primary melanoma on the skin very accurately indicates whether it has spread to the regional lymph nodes (e.g. in the groin, the armpit or the neck) has occurred. This means that patients who are at the highest risk of later developing melanoma-related problems are identified at an early stage of the disease. What is not yet clear is whether this earlier identification makes any difference to the ultimate outcome, and this is one of the important things that will be clarified by the results of the Multi-Center Selective Lymphadenectomy Trial*. It is also clear at this stage that the likelihood of a sentinel lymph node containing metastatic (secondary) melanoma cells is closely related to primary tumour thickness (routinely measured in millimetres by the pathologist).
The Sydney Melanoma Unit’s experience is that if the primary tumour is less that 1.5mm in thickness, the risk of the tumour having spread to the lymph nodes is 5%, if the primary tumour is between 1.5mm and 3mm the risk is 14%, and if the primary tumour is more than 3mm in thickness, the risk is 24%.
At this stage Dicarbazine, Interferon and Yervoy may be used as a form of chemotherapy in the treatment of metastatic melanoma. The use of these different agents is at the discretion of an oncologist and may be up to a number of factors specific to the individual patient.
Interferon can be used as an adjunctive therapy for melanoma patients who may have had metastatic melanoma, but have no known disease present at the time. It takes the form of a month course of Intravenous administration followed by a course of adjunctive therapy. The side effects of this can be quite severe and constant consultation with your oncologist is needed during treatment.
Does Interferon prevent melanoma recurrence?
The interferons are a family of proteins produced by the body’s immune system. They serve a variety of purposes, including helping to defend against viruses, like influenza. There is good laboratory evidence, and some clinical evidence, that they also work to kill melanoma cells, both directly and also by stimulating the immune system to attack the cancer cells. The main interferon that works against melanoma is called interferon-alpha.
For over 10 years a vigorous debate has taken place between melanoma specialists as to whether or not interferon protects people from recurrence of melanoma, once they have had a melanoma removed.
Throughout the 1980’s and ’90’s a series of clinical trials was performed in the USA and Europe to investigate the use of interferon-alpha in reducing the risk of recurrence after high-risk melanoma had been removed. Unfortunately, the results of those trials were very confusing due to different groups of patients tested, different dosage schedules chosen, and other factors.
There is now fairly good evidence that low dose and intermediate dose interferon have little effect, but a serious question mark remains over the use of high-dose interferon, or “HDI”. Three trials suggest that HDI significantly prolongs the time between the initial melanoma and any relapse that may occur. However, HDI involves giving the drug via a drip into the vein daily for a month as an outpatient. The side-effects of this treatment are considerable, and may include fevers, fatigue, muscle pains and mood disturbance. Many of these side-effects can be controlled and modified, but patients receiving the treatment require careful monitoring and special nursing care
There are other forms of chemotherapy being used in a trial stage for malignant melanoma where there is metastases present that can be monitored and measured in response to the treatment. Your oncologist will be able to discuss the relevant options that are applicable to you and your journey.
This form of treatment uses x-rays to kill cancer cells by targeting the cancer sites within the body. Treatment is carefully planned to do little harm as possible to the bodies normal tissue.Radiotherapy may be used when metastatic melanoma has spread to an internal organ or as a preventative after excision of melanoma. It has also been used with the goal of reducing tumour size when there are complications arising from the tumour.
Gamma Knife therapy is targeted radiotherapy to tumours that are present in the brain and can be used for metastatic melanoma patients.
Radiotherapy can cause temporary side effects including tiredness, nausea, irritation of the skin and hair loss.
In most patients, melanoma in the skin creates an immune response against itself. This is seen in the partial regression of primary melanoma on the skin. In some instances the primary melanoma disappears completely from the skin, but not before melanoma cells spread from the skin to other sites in the body, such as regional lymph nodes. This is referred to as occult melanoma.
Once melanoma has spread from the skin, natural responses by the immune system are less effective in controlling tumour growth. This may be because the immune response is less effective in particular parts of the body to which melanoma has spread or because the tumour cells undergo changes which make them less susceptible to the immune system. Over time, interaction between melanoma cells and the immune system also leads to change in immune responses that make them less effective in killing melanoma cells. These changes lead to the tumour becoming “immunologically silent” in patients.
Various strategies are being tested to use immunotherapy against melanoma. Immunisation with melanoma vaccines aims to increase immune responses against the patient’s melanoma and to change the nature of the immune response to be more effective against melanoma. At present, the following programs are in progress.
1. Immunisation with Dendritic Cell Vaccines
2. Immunisation with Extracts of the Patient’s Melanoma
3. Immunisation with “Allogeneic” Vaccines or Synthetic Melanoma Antigens