Preoperative radiotherapy in the management of retroperitoneal liposarcoma.
BACKGROUND
Histological subtype influences both prognosis and patterns of treatment failure in retroperitoneal sarcoma. Previous studies on the efficacy of neoadjuvant radiotherapy (NRT) have incorporated multiple histological types with heterogeneous tumour biology. The survival impact of NRT specifically for patients with retroperitoneal liposarcoma is poorly defined.


METHODS
Patients who underwent resection with curative intent for retroperitoneal liposarcoma and who received NRT or surgery alone were identified in the US National Cancer Data Base (2004-2013). Cox regression was used to identify co-variables associated with overall survival. NRT and surgery-alone cohorts were matched 1 : 1 by propensity scores based on the survival hazard on Cox modelling. Overall survival was compared by Kaplan-Meier estimates.


RESULTS
A total of 2082 patients with retroperitoneal liposarcoma were identified; 1908 underwent surgery alone and 174 received NRT before surgical resection. Median tumour size was 22·0 cm and 34·9 per cent of tumours were high grade. In the unmatched cohort, NRT was not associated with improved overall survival (χ2= 3·49, P = 0·062). In the propensity score-matched cohort, NRT was associated with an improvement in survival (median overall survival 129·2 versus 84·3 months; P = 0·046; hazard ratio (HR) 1·54, 95 per cent c.i. 1·01 to 2·36). This effect appeared most pronounced for tumours with adjacent organ invasion (median overall survival not reached versus 63·8 months; P = 0·044; HR 1·79, 1·01 to 3·19).


CONCLUSIONS
NRT improved survival in patients undergoing surgery for retroperitoneal liposarcoma, particularly those with high-risk pathological features.
Departments of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
B L
BL
Ecker
Departments of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
M G
MG
Peters
Departments of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
M T
MT
McMillan
Departments of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
A J
AJ
Sinnamon
Departments of Pathology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
P J
PJ
Zhang
Departments of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
D L
DL
Fraker
Departments of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
W P
WP
Levin
Departments of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
R E
RE
Roses
Departments of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
G C
GC
Karakousis
D000368:Aged; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008080:Liposarcoma / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D008297:Male; D000072662:Margins of Excision; D008875:Middle Aged; D060787:Neoplasm Grading; D011300:Preoperative Care / Q000379:methods / Q000401:mortality; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D012186:Retroperitoneal Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D012189:Retrospective Studies; D047368:Tumor Burden