Influence of noncompliance with radiation therapy protocol guidelines and operative bed recurrences for children with rhabdomyosarcoma and microscopic residual disease: a report from the Children's Oncology Group.
OBJECTIVE
Postoperative radiation therapy (RT) is recommended for patients with rhabdomyosarcoma having microscopic disease. Sometimes RT dose/volume is reduced or omitted in an attempt to avoid late effects, particularly in young children. We reviewed operative bed recurrences to determine if noncompliance with RT protocol guidelines influenced local-regional control.


METHODS
All operative bed recurrences among 695 Group II rhabdomyosarcoma patients in Intergroup Rhabdomyosarcoma Study Group (IRS) I through IV were reviewed for deviation from RT protocol. Major/minor dose deviation was defined as >10% or 6-10% of the prescribed dose (40-60 Gy), respectively. Major/minor volume deviation was defined as tumor excluded from the RT field or treatment volume not covered by the specified margin (preoperative tumor volume and 2- to 5-cm margin), respectively. No RT was a major deviation.


RESULTS
Forty-six of 83 (55%) patients with operative bed recurrences did not receive the intended RT (39 major and 7 minor deviations). RT omission was the most frequent RT protocol deviation (19/46, 41%), followed by dose (17/46, 37%), volume (9/46, 20%), and dose and volume deviation (1/46, 2%). Only 7 operative bed recurrences occurred in IRS IV (5% local-regional failure) with only 3 RT protocol deviations. Sixty-three (76%) patients with recurrence died of disease despite retrieval therapy, including 13 of 19 nonirradiated children.


CONCLUSIONS
Over half of the operative bed recurrences were associated with noncompliance; omission of RT was the most common protocol deviation. Three fourths of children die when local-regional disease is not controlled, emphasizing the importance of RT in Group II rhabdomyosarcoma.
Million
Lynn
L
Department of Radiation Oncology, University of Utah Health Sciences and Huntsman Cancer Institute, Salt Lake City, UT, USA. lynn.million@hci.utah.edu
Anderson
James
J
Breneman
John
J
Hawkins
Douglas S
DS
Laurie
Fran
F
Michalski
Jeff
J
Rodeberg
David
D
Wharam
Moody
M
Wolden
Suzanne
S
Donaldson
Sarah S
SS
D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D002985:Clinical Protocols; D019983:Guideline Adherence; D006801:Humans; D007223:Infant; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000532:radiotherapy*; D018365:Neoplasm, Residual; D011879:Radiotherapy Dosage; D018232:Rhabdomyosarcoma, Alveolar / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018233:Rhabdomyosarcoma, Embryonal / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D047368:Tumor Burden