Importance of a post-therapeutic residue in the prognosis of head and neck rhabdomyosarcoma in children.

Enhanced contrast computed tomography (CT) was performed in 23 children treated for head and neck rhabdomyosarcoma (RMS). The CT studies were retrospectively reviewed by two senior radiologists. Analysis of these CT studies revealed to separate groups of patients. One group (12 patients) had a post-therapeutic residue defined as soft tissue thickening at the original site, which remained stable over a period of 3 months and caused no mass effect on adjacent structures. Of these 12, eight showed enhancement at the area of thickening. Nine of these 12 patients relapsed. The other group (11 patients) demonstrated no post-therapeutic residue; only three of these patients relapsed. In this study the presence of a post-therapeutic residue was significantly associated with a poor prognosis, using a Fischer's test (P = 0.04).