Gemcitabine Induced Radiation Recall Myositis In A Patient With Relapsed Nasopharyngeal Carcinoma

Combined modality therapy with surgery, irradiation, and chemotherapy is the standard of care for many pediatric solid tumors. Although the adverse effects of an individual modality are well known, the adverse events resulting from interaction between the modalities is not well understood. The toxicity of radiation therapy is influenced by multiple factors, including the tissue volume irradiated (daily and cumulative dose), fraction size and schedule, treatment techniques, patient age, physiologic reserve, comorbidities, and genetics. Radiation therapy toxicity may also depend on concomitant chemotherapy; a quintessential example is the phenomenon of “radiation recall” reaction secondary to subsequent systemic chemotherapy.1 D’Angio initially described a radiation recall reaction as an acute inflammatory response evident in previously irradiated fields that is induced when chemotherapy is administered after radiation therapy.1 Chemotherapeutic agents reported to cause a radiation recall reaction include dactinomycin, anthracyclines (doxorubicin), taxanes (docetaxel), and antimetabolites (gemcitabine).2‐4 It is unclear whether the association of a radiation recall reaction with