Is there a role for FDG-PET for the assessment of treatment efficacy in Wilms' tumor? A case report and literature review.

BACKGROUND: The role of FDG-PET in Wilms' tumor has not been well established. The aim of this report is to describe the role of FDG-PET to assess chemotherapy efficacy and to show potential correlations between different Standardized Uptake Values (SUVs) and histopathological features in a patient with persisting metastatic disease. CASE DESCRIPTION: A 3-year-old boy was diagnosed with Wilms' tumor without anaplasia. The patient underwent treatment as according to the AIEOP-TW-2003 protocol, for stage III tumors. Therapy was discontinued with no evidence of disease, yet 9 months later thorax metastases were found. Although second and third line treatments were administered, conventional imaging demonstrated stable disease. Metronomic chemotherapy as well was employed for 44 months and FDG-PET was annually performed basing on responsible local physician choice trying to better describe the disease status. Four months after fourth line treatment was stopped, the patient manifested clinical symptoms; lesions began to increase their metabolic activity inhomogeneously. Therapy was hence restarted and SUVs decreased. Metastasectomies were then performed and histology revealed a correlation between viable disease shown by higher FDG-PET uptake and viable tumor areas. CONCLUSIONS: Our case discussion demonstrates that FDG-PET is potentially valuable in Wilms' tumor correlating SUV values and histological features of the tumor after chemotherapy. This case suggests that FDG-PET is a valid tool to assess chemotherapy response in relapsed Wilms' tumor even in case of no evidence of significant dimensional changes under conventional imaging.

Is alveolar histotype a prognostic factor in paratesticular rhabdomyosarcoma? The experience of Italian and German Soft Tissue Sarcoma Cooperative Group.

PURPOSE: To ascertain whether alveolar histology retains its adverse prognostic role in the subset of paratesticular rhabdomyosarcoma (RMS) patients, generally characterized by a very good outcome. PATIENTS AND METHODS: Twenty pediatric patients were treated over a 25-year period using the protocols of the Italian and German Soft Tissue Sarcoma Cooperative Groups. Clinical characteristics at presentation were much the same as in non-alveolar patients. RESULTS: The proportion of patients with alveolar histotype (8%) in paratesticular site was lower than in the general RMS population (20-30%). With a median follow-up of 122 months, 5-year EFS and OS were 78 and 89%, respectively. CONCLUSION: Our data suggest a distinctly better clinical behavior of paratesticular alveolar RMS than when the disease occurs at other sites. These patients were more intensively treated than the embryonal cases, however, so-although a treatment intensity reduction may be desiderable-the idea of eliminating the alkylating agents (as in low-risk embryonal paratesticular RMS) must be considered with great caution.