Positron Emission Tomography (PET) Evaluation After Initial Chemotherapy and Radiation Therapy Predicts Local Control in Rhabdomyosarcoma

• Published in: International journal of radiation oncology, biology, physics Vol. 84; no. 4; pp. 996 - 1002
• Main Authors: Dharmarajan, Kavita V., MD, Wexler, Leonard H., MD, Gavane, Somali, MD, Fox, Josef J., MD, Schoder, Heiko, MD, Tom, Ashlyn K., BS, Price, Alison N., BS, Meyers, Paul A., MD, Wolden, Suzanne L., MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 15.11.2012; Elsevier
• Subjects: Adolescent; Adult; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Biological and medical sciences; CHEMOTHERAPY; Child; Child, Preschool; Combined Modality Therapy - methods; COMPARATIVE EVALUATIONS; Dermatology; Disease-Free Survival; Diseases of the osteoarticular system; FAILURES; Female; FLUORODEOXYGLUCOSE; Fluorodeoxyglucose F18; Hematology, Oncology and Palliative Medicine; Humans; Infant; Local control; Male; Medical sciences; MYOSARCOMAS; PATIENTS; POSITRON COMPUTED TOMOGRAPHY; Positron emission tomography; Positron-Emission Tomography - methods; Radiation therapy; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; Radiopharmaceuticals; RADIOTHERAPY; Radiotherapy Dosage; Retrospective Studies; Rhabdomyosarcoma; Rhabdomyosarcoma - diagnostic imaging; Rhabdomyosarcoma - drug therapy; Rhabdomyosarcoma - pathology; Rhabdomyosarcoma - radiotherapy; ROC Curve; Treatment Outcome; Treatment response; Tumors of striated muscle and skeleton; Tumors of the skin and soft tissue. Premalignant lesions; Young Adult; Treatment response; Radiation therapy; Local control; Positron emission tomography; Rhabdomyosarcoma; Radionuclide study; Treatment efficiency; Soft tissue sarcoma; Malignant tumor; Radiotherapy; Striated muscle disease; Chemotherapy; Treatment; Cancerology; Predictive factor; Cancer; Emission tomography
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2012.01.077

Purpose 18-fluorodeoxyglucose positron emission tomography (PET) is already an integral part of staging in rhabdomyosarcoma. We investigated whether primary-site treatment response characterized by serial PET imaging at specific time points can be correlated with local control. Patients and Methods We retrospectively examined 94 patients with rhabdomyosarcoma who received initial chemotherapy 15 weeks (median) before radiotherapy and underwent baseline, preradiation, and postradiation PET. Baseline PET standardized uptake values (SUVmax) and the presence or absence of abnormal uptake (termed PET-positive or PET-negative) both before and after radiation were examined for the primary site. Local relapse-free survival (LRFS) was calculated according to baseline SUVmax, PET-positive status, and PET-negative status by the Kaplan-Meier method, and comparisons were tested with the log-rank test. Results The median patient age was 11 years. With 3-year median follow-up, LRFS was improved among postradiation PET-negative vs PET-positive patients: 94% vs 75%, P =.02. By contrast, on baseline PET, LRFS was not significantly different for primary-site SUVmax ≤7 vs >7 (median), although the findings suggested a trend toward improved LRFS: 96% for SUVmax ≤7 vs 79% for SUVmax >7, P =.08. Preradiation PET also suggested a statistically insignificant trend toward improved LRFS for PET-negative (97%) vs PET-positive (81%) patients ( P =.06). Conclusion Negative postradiation PET predicted improved LRFS. Notably, 77% of patients with persistent postradiation uptake did not experience local failure, suggesting that these patients could be closely followed up rather than immediately referred for intervention. Negative baseline and preradiation PET findings suggested statistically insignificant trends toward improved LRFS. Additional study may further understanding of relationships between PET findings at these time points and outcome in rhabdomyosarcoma.