Correlation of intraoperatively irradiated volume and fibrosis in patients with soft-tissue sarcoma of the extremities.
OBJECTIVE
To investigate the influence of intraoperatively irradiated volume on soft-tissue fibrosis.


METHODS
Fifty-three patients with soft-tissue sarcoma of the extremities were treated with intraoperative radiotherapy (IORT) (median dose 15 Gy) and postoperative fractionated therapy (median dose 46 Gy). The median follow-up was 41.5 months (range 18-94). Late toxicity was classified according to the LENT-SOMA criteria. A Cox regression model was calculated to identify the parameters that could influence soft-tissue fibrosis Grade 3 or 4. Five parameters were observed: extent of surgical procedure, IORT in case of recurrence, extent of IORT volume, extent of IORT dose, and extent of postoperative volume. In addition, a logistic regression model was calculated to demonstrate the relationship between the IORT volume and fibrosis development.


RESULTS
The overall survival rate after 5 years was 84%. The actuarial tumor control rate was 90% after 5 years. Eleven patients developed soft-tissue fibrosis. Five patients developed Grade 3 fibrosis and 1 patient developed Grade 4 fibrosis. Only the IORT volume had a significant influence on Grade 3 or 4 fibrosis development. An IORT volume of 210 cm(3) conveyed a 5% risk (confidence interval 1-20%) of the development of severe fibrosis. The risk of severe Grade 3 or 4 fibrosis increased to 50% (confidence interval 15-80%) if a volume of 420 cm(3) was irradiated.


CONCLUSIONS
The effect of volume in patients treated with IORT was remarkable. The ratio of side effects was relatively low. The risk of soft-tissue Grade 3 or 4 fibrosis increased with the extent of the IORT volume. Compared with the literature, IORT provides excellent local control in these patients.
van Kampen
M
M
Clinical Radiology (with focus on Radiotherapy) and Policlinic, Radiologic University Hospital, University of Heidelberg, Heidelberg, Germany. m.van_kampen@t-online.de
Eble
M J
MJ
Lehnert
T
T
Bernd
L
L
Jensen
K
K
Hensley
F
F
Krempien
R
R
Wannenmacher
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D016001:Confidence Intervals; D003238:Connective Tissue / Q000473:pathology / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005121:Extremities; D005355:Fibrosis / Q000209:etiology; D005500:Follow-Up Studies; D018219:Histiocytoma, Benign Fibrous / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D007432:Intraoperative Period; D008080:Liposarcoma / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D009442:Neurilemmoma / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D012044:Regression Analysis; D016019:Survival Analysis; D014945:Wound Healing