Intralesional Immunotherapy for Metastatic Melanoma: The Oldest and Newest Treatment in Oncology.

The last few years have yielded exciting developments in immunotherapy for cancer. The promise of cancer immunotherapy has been well known for many years, but had generally produced limited or inconsistent benefit to patients. Intralesional therapies, which are in fact one of the oldest forms of immunotherapy, are also demonstrating benefits in the modern age. This review discusses the origins of intralesional immunotherapy and its underlying rationale. It also discusses the reemergence of this mode of therapy into the modern era, which is where Donald L. Morton, subject of this edition of the journal, plays a major role. The review also discusses current areas of investigation. Given the intuitive advantages of this strategy and the demonstrated, expanding areas of clinical responses, it is likely that intralesional immunotherapy will remain a useful component of cancer treatment into the future.