Clinical and theoretical aspects of the treatment of surgically unresectable retroperitoneal malignancy with combined intra‐arterial actinomycin‐d and radiotherapy

A small pilot series (eight patients) of surgically unresectable retroperitoneal tumors treated with radiotherapy and a selective, prolonged, continuous intraarterial infusion of actinomycin‐D is discussed, in addition to the possible theoretical advantages for this therapy. For such tumors, there is a very low probability of obtaining local control with conventional radiotherapy alone. However, on the basis of recent knowledge from radiobiology and molecular biology, the technique is a rational attempt to improve the local control probability. Geographic miss with radiotherapy portals is another major cause for local failure with such tumors. We also emphasize the importance of detailed tumor localization procedures. The local responses, some of the local controls, the palliation achieved, and the lack of significant morbidity with this technique have been encouraging. We therefore consider it worthy of further clinical investigation.