The prognostic significance of residual pigmentation following radiotherapy of epidemic Kaposi's sarcoma.
The response to radiotherapy of epidemic Kaposi's sarcoma (EKS) is unusual in that irradiated regions are frequently left with a persistent purple stain, reminiscent of the color of the original tumor, but with no tumor mass. To date there are no published data to indicate whether the persistence of pigmentation can be predicted beforehand or if it has any prognostic import. We reviewed the response to treatment of 118 EKS lesions that were irradiated at New York University (NYU) Medical Center between 1981 and 1986. A total of 86 responded to treatment by complete clearance of the mass. Of these, 29 left residual purple pigmentation within the treatment portal, while 57 did not. Complete response (CR; without residual pigmentation) occurred more often in patients who had higher Karnofsky scores at the time of treatment. However, in terms of ultimate local control or survival, there were no differences between patients whose lesions cleared completely v those in whom pigmentation remained. We conclude that persistent pigmentation represents only a benign remnant of irradiated EKS and has no prognostic import.