Recognizing cisplatin as a potential radiation recall trigger: case report and focused systematic review

We present a case of mild radiation recall dermatitis triggered by cisplatin chemotherapy given simultaneously to re-irradiation. The dermatitis area correlated to skin exposure of the previous radiation therapy, characterizing the reaction clearly as a recall. Cisplatin has not yet been recognized as a potential trigger for recall reactions. Although it was part of several reported multidrug trigger combinations, all review works referred to cisplatin as not suspicious, suggesting the combination partner as the effector. We performed a focused systematic literature review aiming to re-evaluate the real role of cisplatin as a (co-)triggering factor. In total, 30 reported cases were found, 90% triggered by multidrug combinations. The latter tended to cause more severe symptoms. Besides findings supporting the 20 Gy-threshold theory, no correlation between radiation dose and severity or prevalence was found. Recognition of cisplatin as a trigger of the recall phenomenon and its supportive management may prevent unnecessary cessation of systemic chemotherapy. Systematic reporting of recall events as a secondary endpoint of prospective clinical trials applying radiation therapy could support understanding the recall phenomenon.