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Histology, Fusion Status, and Outcome in Alveolar Rhabdomyosarcoma With Low‐Risk Clinical Features: A Report From the Children's Oncology Group
Author(s) -
Arnold Michael A.,
Anderson James R.,
GastierFoster Julie M.,
Barr Frederic G.,
Skapek Stephen X.,
Hawkins Douglas S.,
Raney R. Beverly,
Parham David M.,
Teot Lisa A.,
Rudzinski Erin R.,
Walterhouse David O.
Publication year - 2016
Publication title -
pediatric blood and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.116
H-Index - 105
eISSN - 1545-5017
pISSN - 1545-5009
DOI - 10.1002/pbc.25862
Subject(s) - medicine , cog , rhabdomyosarcoma , alveolar rhabdomyosarcoma , stage (stratigraphy) , histology , oncology , pathology , sarcoma , paleontology , artificial intelligence , computer science , biology
Background Distinguishing alveolar rhabdomyosarcoma (ARMS) from embryonal rhabdomyosarcoma (ERMS) is of prognostic and therapeutic importance. Criteria for classifying these entities evolved significantly from 1995 to 2013. ARMS is associated with inferior outcome; therefore, patients with alveolar histology have generally been excluded from low‐risk therapy. However, patients with ARMS and low‐risk stage and group (Stage 1, Group I/II/orbit III; or Stage 2/3, Group I/II) were eligible for the Children's Oncology Group (COG) low‐risk rhabdomyosarcoma (RMS) study D9602 from 1997 to 1999. The characteristics and outcomes of these patients have not been previously reported, and the histology of these cases has not been reviewed using current criteria. Procedure We re‐reviewed cases that were classified as ARMS on D9602 using current histologic criteria, determined PAX3/PAX7‐FOXO1 fusion status, and compared these data with outcome for this unique group of patients. Results Thirty‐eight patients with ARMS were enrolled onto D9602. Only one‐third of cases with slides available for re‐review (11/33) remained classified as ARMS by current histologic criteria. Most cases were reclassified as ERMS (17/33, 51.5%). Cases that remained classified as ARMS were typically fusion‐positive (8/11, 73%), therefore current classification results in a similar rate of fusion‐positive ARMS for all clinical risk groups. In conjunction with data from COG intermediate‐risk treatment protocol D9803, our data demonstrate excellent outcomes for fusion‐negative ARMS with otherwise low‐risk clinical features. Conclusions Patients with fusion‐positive RMS with low‐risk clinical features should be classified and treated as intermediate risk, while patients with fusion‐negative ARMS could be appropriately treated with reduced intensity therapy.