(P 040) TWO RARE SIDES OF ONE RARE DISEASE: EWING SARCOMA WITH AND AS SECONDARY MALIGNANCIES FROM THE EPIDEMIOLOGICAL AND CLINICAL ANALYSIS OF AN INTERNATIONAL TRIAL REGISTRY

Author(s)

Stefan K. Zöllner, MD (he/him/his)

Fellow
University Hospital Essen, Pediatrics III, Essen, Germany
Nottuln, Nordrhein-Westfalen, Germany

Co-Author(s)

KK

Katja Kauertz, N/A, n/a

University Hospital Essen, Pediatrics III, Essen, Germany
Düsseldorf, Nordrhein-Westfalen, Germany
Isabelle Kaiser, MD

MD
University Hospital Essen, Pediatrics III, Essen, Germany
Essen, Nordrhein-Westfalen, Germany
CS

Christiane Schaefer, N/A, n/a

University Hospital Essen, Pediatrics III, Essen, Germany
Essen, Nordrhein-Westfalen, Germany
HJ

Heribert Jürgens, N/A, n/a

University Children’s Hospital Münster, West German Cancer Center Network, Department of Pediatric Hematology and Oncology, Münster, Germany
Münster, Nordrhein-Westfalen, Germany
RL

Ruth Ladenstein, N/A, n/a

Children's Cancer Research Institute, Paediatric Oncology, Vienna, Austria
Vienna, Wien, Austria
MP

Michael Paulussen, N/A, n/a

Vestische Children’s and Youth Hospital Datteln, Pediatric Hematology and Oncology, Datteln, Germany
Datteln, Nordrhein-Westfalen, Germany
Thomas Kühne, MD (he/him/his)

Acting Head of Division
University Children´s Hospital Basel, Department of Oncology/ Haematology, Basel, Switzerland
Basel, Basel-Stadt, Switzerland
LH

Lianne Haveman, N/A, n/a

Prinses Máxima Centrum voor Kinderoncologie, Pediatric Oncology, Utrecht, Netherlands
Utrecht, Utrecht, Netherlands
WH

Wolfgang Hartmann, N/A, n/a

University Hospital Muenster, West German Cancer Center Network, Gerhard Domagk Institute for Pathology, Münster, Germany
Münster, Nordrhein-Westfalen, Germany
TL

Thorsten Langer, N/A, n/a

University Hospital for Children and Adolescents, Pediatric Oncology and Hematology, Lübeck, Germany
Lübeck, Schleswig-Holstein, Germany
AR

Andreas Ranft, N/A, PhD

University Hospital Essen, Pediatrics III, Essen, Germany
Essen, Nordrhein-Westfalen, Germany
UD

Uta Dirksen, N/A, MD

University Hospital Essen, Pediatrics III, Essen, Germany
Essen, Nordrhein-Westfalen, Germany

Objective: Intensive, multimodality treatment of Ewing sarcoma (EwS) improves survival at the expense of late e!ects such as secondary malignant neoplasms (SMN). Patients with secondary EwS are excluded from risk stratification in several studies and therefore do not benefit from new therapies. More knowledge about EwS patients with SMN or as SMN is needed to identify at-risk patients and adapt follow-up strategies.

Methods: Epidemiology and clinical characteristics of EwS patients with SMN or as SMN were analyzed in 4518 and 3874 patients treated in the last five and three consecutive international EwS trials, CESS81, CESS86, EICESS92, Euro-E.W.I.N.G.99, and EWING2008, respectively.

Results: Ninety-six patients developed SMN after primary EwS, with solid tumors detected more frequently than hematologic neoplasms (55.2% and 44.8%, respectively). The median latency between EwS and first SMN was 4.9 years (range, 0.1-28.1), with a significant difference of 6.1 years between earlier development of hematologic malignancies compared with solid tumors (P<.001). The clinical characteristics of the primary EwS did not differ between patients with and without SMN. All patients received multichemotherapy, with 80.2% receiving adjuvant radiotherapy.

Forty-four cases of secondary EwS were reported, preceded by a heterogeneous group of malignancies, mainly acute lymphoblastic leukemias (n=7) and lymphomas (n=7). Two cases (7.6%) occurred in the radiation field of the primary tumor. The median age at diagnosis of secondary EwS was 21.4 years (range, 5.9-72) compared with 10.9 years (range, 0.9-53.5) for primary EwS. The 3-year OS/EFS was 0.70 (SE=.09)/0.55 (SE=.10) for localized patients and 0.33 (SE=.12)/0.27 (SE =.11) for metastatic patients (OS: P=.01). Survival in secondary EwS did not differ between hematologic or solid primary malignancies.

Conclusion: SMN after EwS remains a rare but severe event and requires a structured follow-up system. EwS as SMN accounts for approximately 1% of all reported EwS, and its risk-adjusted treatment should be curative, especially in localized patients.