Regional therapies for locoregionally advanced and unresectable melanoma.

Locoregionally advanced and unresectable disease can be seen in up to 10% of melanoma patients. Treatment options for these patients have been evolving most notably over the past few decades and have demonstrated efficacy through multiple intra-arterial as well as intralesional therapies. Isolated limb perfusions and isolated limb infusions have been utilized to treat locoregionally advanced melanoma of the extremity with overall response rates up to 90% in some reports. Intralesional therapies, for in transit metastatic melanoma, such as Bacille Calmette-Guerin, talimogene laherparepvec, and PV-10 (Rose Bengal) have all demonstrated efficacy in the treatment of unresectable cutaneous melanoma. The treatment effect due to intralesional injection has been identified in directly injected lesions as well as in distant uninjected "bystander lesions" with some injectables. This bystander effect is likely an immunologic reaction due to tumor antigen release, antigen-presenting cell uptake, T cell activation and subsequent bystander tumor destruction in uninjected lesions. Treatment options for unresectable melanoma metastases limited to the liver include isolated hepatic perfusion, which can now be performed through a minimally invasive approach known as percutaneous hepatic perfusion. These intra-arterial and intralesional regional therapies offer a variety of effective treatment modalities for unresectable disease and may potentially be combined with systemic treatments, such as immunotherapy, in the future treatment of locoregionally advanced melanoma.