title: Use of MR imaging to assess results of chemotherapy for Ewing sarcoma.
abstract: MR imaging was used to monitor the results of initial chemotherapy of primary Ewing sarcoma of bone. The signal intensities of the soft-tissue and marrow components of the tumor were evaluated on T2-weighted images obtained in 10 patients (nine with responsive tumors) at presentation and during and immediately after completion of two cycles of chemotherapy. MR evidence of marrow and soft-tissue involvement was seen in all tumors at presentation. After treatment, the bone-marrow component of the nine drug-sensitive tumors showed an increase in signal intensity that in eight cases became comparable to that of water. Changes in signal intensity of the soft-tissue component were variable, consisting of increases in two of the responsive lesions, no change in three, a decrease in two, and complete resolution of the soft-tissue mass in two. There was no increase in signal intensity of either the bone-marrow or the soft-tissue component of the single nonresponsive tumor. All of the responsive tumors showed advanced healing, and abundant bony sclerosis was apparent on CT. Bone-marrow examinations, performed in seven of the nine patients with responsive lesions, disclosed no evidence of tumor in four. Two patients had residual extramedullary tumor; the nonresponsive lesion contained sheets of tumor cells. The increase in marrow signal intensity on T2-weighted images was associated with replacement of marrow elements by a loose, hypocellular myxoid matrix containing modest amounts of collagen, consistent with response to chemotherapy and eradication of disease. Therefore, an increase in the T2-weighted signal intensity of the bone-marrow component of Ewing sarcoma of bone reflected a favorable response to chemotherapy. MR signal changes, however, were not predictive of resolution of malignant disease within adjacent soft tissue.
authors.affiliation: Department of Radiology, St. Jude Children's Research Hospital, Memphis, TN 38101-0318.
authors.forename: M A
authors.initials: MA
authors.lastname: Lemmi
authors.forename: B D
authors.initials: BD
authors.lastname: Fletcher
authors.forename: N M
authors.initials: NM
authors.lastname: Marina
authors.forename: W
authors.initials: W
authors.lastname: Slade
authors.forename: D M
authors.initials: DM
authors.lastname: Parham
authors.forename: J J
authors.initials: JJ
authors.lastname: Jenkins
authors.forename: W H
authors.initials: WH
authors.lastname: Meyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000175:diagnosis / Q000188:drug therapy*; D002648:Child; D003520:Cyclophosphamide / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage; D004334:Drug Administration Schedule; D005047:Etoposide / Q000008:administration & dosage; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007069:Ifosfamide / Q000008:administration & dosage; D008279:Magnetic Resonance Imaging; D008297:Male; D012512:Sarcoma, Ewing / Q000175:diagnosis / Q000188:drug therapy*
chemical_list: D005047:Etoposide; D004317:Doxorubicin; D003520:Cyclophosphamide; D007069:Ifosfamide