Brief overview of treatment options
Surgical Resection of Melanoma
The primary treatment for melanoma is surgical resection, typically including a wide local excision of the primary melanoma skin lesion, plus sampling of the nearby lymph nodes if the primary melanoma lesion invades deeply (1, 2, 3, 4). For primary melanoma lesions that arise internally, such as those that arise in the sinuses, surgical removal plus post-operative radiotherapy seems to give the best result, although high-dose radiotherapy alone may also have curative potential in patients who are inoperable (5, 6).
In more advanced cases, selective resection of metastatic lesions (metastectomy) may also increase the disease-free interval (7, 8, 9). Because long-term survivors may be seen at all stages of melanoma, aggressive surgical or radiotherapy treatment of primary melanoma lesions, regional lymph nodes or even limited metastatic disease may be appropriate, depending upon the particular situation (7). Resection of melanoma lesions involving the lung has produced a 22% 5-year survival in one reported series, indicating that even if “vital organs” are involved, long-term survival is possible (8).
Radiotherapy for Melanoma
Although melanoma is typically regarded as one of the “radioresistant” malignancies, a high percentage of superficially extensive primary melanoma lesions have actually been cured by high dose per treatment radiotherapy, in patients who have received radiotherapy to avoid a disfiguring operation (10). Radiotherapy also appears useful in controlling neck disease (lymph nodes) in primary melanoma of head and neck origin, allowing some patients to avoid more radical surgery (neck dissection) (11,12).
Skin/Soft tissue melanoma lesions and radiobiology
Radiotherapy also appears useful in controlling neck disease (lymph nodes) in primary melanoma of head and neck origin, allowing some patients to avoid more radical surgery (neck dissection) (13, 14, 15) although one study showed no difference in the response rate of metastatic melanoma lesions to hypofractionated radiotherapy versus conventional radiotherapy, with a response rate of approximately 60% for each tested regimen (16).
These contradictory findings likely indicate that melanomas represent a diverse group of tumors, some responding uniquely well to hypofractionated radiotherapy, while others respond well to either form of radiotherapy.
In contradistinction to the relatively favorable response rate of soft tissue melanoma metastases (16), melanoma metastatic to the brain responds poorly to conventional radiotherapy, with a reported 3 month median survival – a response that barely exceeded supportive care only (9). More favorable survival in this setting has been reported with surgical resection with or without post-operative whole brain radiotherapy (9).
Conventional radiotherapy summary
In summary, the discrepant literature results suggest that melanomas are actually a biologically heterogenous group, with skin and soft tissue lesions apparently responding more favorably to radiotherapy than brain lesions, and some studies strongly suggesting a more favorable response to large dose per fraction (hypofractionation) radiotherapy regimens.