Positron emission tomography for response assessment in desmoplastic small round cell tumor.
BACKGROUND
Desmoplastic small round cell tumors (DSRCT) typically have a large stromal component and often are extensively disseminated in the peritoneal cavity at diagnosis. These factors contribute to difficulty in quantifying response to chemotherapy using RECIST or WHO criteria. This study compares the overall disease response to chemotherapy by fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) in patients with DSRCT.


METHODS
We conducted a retrospective chart review of 7 patients with DSRCT who were imaged by FDG-PET and CT at diagnosis and after 3 cycles of chemotherapy. Response to chemotherapy was graded according to EORTC metabolic response guidelines and RECIST.


RESULTS
All tumors demonstrated some decrease in SUVmax (51%±21%) and longest diameter (23%±8%) with chemotherapy. The best response achieved by FDG-PET was a partial response in 6 patients and by CT was a partial response in 1 patient. Measured response was concordant between the 2 modalities in 2 patients.


CONCLUSIONS
In this small series response measurement by FDG-PET did not always correlate with response measurement by CT. A greater decrease in metabolic activity as compared with size was seen in all patients. Further studies are needed to define the role of FDG-PET in assessing early response of DSRCT to chemotherapy.
Department of Pediatrics, Nuclear Medicine Service, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. magnanh@mskcc.org
Heather
H
Magnan
Sara J
SJ
Abramson
Anita P
AP
Price
Ravinder K
RK
Grewal
Melinda S
MS
Merchant
Michael P
MP
LaQuaglia
Paul A
PA
Meyers
D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging*; D000293:Adolescent; D058405:Desmoplastic Small Round Cell Tumor / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D010386:Pelvic Neoplasms / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18