An interesting case of possible abscopal effect in malignant melanoma

The natural history of malignant melanoma is notoriously unpredictable. Although long-term survival is not uncommon (Cade, 1961), lymph node involvement lowers the five-year survival rate to about 5 per cent (Ackerman and Del Regato, 1970). It is generally accepted that radiation has no place in the treatment of metastases (Edwards, 1949; Kunkler and Rains, 1959) despite occasional reports of temporary tumour regression (Ellis, 1939; Sandeman, 1966). In these cases the response to irradiation occurred in the treated area and simultaneous regression of distant untreated metastases has never been reported. Such behaviour has been given the term “abscopal effect”. It occurs not uncommonly in leukaemia but is extremely rare in other tumours and the case reported below is therefore of interest.