Limb-sparing management with surgical resection, external-beam and intraoperative electron-beam radiation therapy boost for patients with primary soft tissue sarcoma of the extremity: a multicentric pooled analysis of long-term outcomes.
OBJECTIVE
A joint analysis of data from three contributing centres within the intraoperative electron-beam radiation therapy (IOERT) Spanish program was performed to investigate the main contributions of IORT to the multidisciplinary treatment of high-risk extremity soft tissue sarcoma (STS).


METHODS
Patients with an histologic diagnosis of primary extremity STS, with absence of distant metastases, undergoing limb-sparing surgery with radical intent, external beam radiotherapy (median dose 45 Gy) and IOERT (median dose 12.5 Gy) were considered eligible for participation in this study.


RESULTS
From 1986-2012, a total of 159 patients were analysed in the study from three Spanish institutions. With a median follow-up time of 53 months (range 4-316 years), 5-year local control (LC) was 82 %. The 5-year IOERT in-field control, disease-free survival (DFS) and overall survival (OS) were 86, 62 and 72 %, respectively. On multivariate analysis, only microscopically involved margin (R1) resection status retained significance in relation to LC (HR 5.20, p < 0.001). With regard to IOERT in-field control, incomplete resection (HR 4.88, p = 0.001) and higher IOERT dose (≥ 12.5 Gy; HR 0.32, p = 0.02) retained a significant association in multivariate analysis.


CONCLUSIONS
From this joint analysis emerges the fact that an IOERT dose ≥ 12.5 Gy increases the rate of IOERT in-field control, but DFS remains modest, given the high risk of distant metastases. Intensified local treatment needs to be tested in the context of more efficient concurrent, neo- and adjuvant systemic therapy.
Department of Oncology, Hospital General Universitario Gregorio Marañón, C/Doctor Esquerdo, 46-28007, Madrid, Spain.
Felipe A
FA
Calvo
Claudio V
CV
Sole
Alfredo
A
Polo
Mauricio
M
Cambeiro
Angel
A
Montero
Ana
A
Alvarez
Miguel
M
Cuervo
Mikel San
MS
Julian
Rafael
R
Martinez-Monge
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy / Q000379:methods / Q000706:statistics & numerical data; D019583:Dose Fractionation, Radiation; D004583:Electrons / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000401:mortality*; D059351:Organ Sparing Treatments / Q000401:mortality*; D015995:Prevalence; D020266:Radiotherapy, Conformal / Q000401:mortality*; D011882:Radiotherapy, High-Energy / Q000401:mortality*; D012189:Retrospective Studies; D012307:Risk Factors; D012509:Sarcoma / Q000401:mortality* / Q000628:therapy*; D013030:Spain / Q000453:epidemiology; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult