PROGNOSTIC FACTORS OF RETROPERITONEAL SARCOMAS

A study examining predictors of outcome following relapse of primary retroperitoneal sarcoma (RPS) found that time to local recurrence or distant metastasis significantly predict survival. Also, patients who undergo resection for the recurrent disease have better survival than others.

“Surgery is the mainstay of curative treatment for RPS, yet a significant proportion of patients experience locoregional and/or distant disease recurrence,” wrote study authors led by Andrea MacNeill, MD, of Princess Margaret Cancer Centre at the University of Toronto. “To date, there are minimal data to guide treatment decisions when a patient with RPS develops recurrent disease.”

The new study examined a series of 1,007 patients with primary RPS treated at eight high-volume centers between January 2002 and December 2011; of those, 408 patients developed recurrent disease. The results of the analysis were published online ahead of print in Cancer.

The initial site of recurrence was local only (LR) in 219 patients, distant only (DM) in 146 patients, and both local and distant (LR + DM) in 43 patients. In the LR patients, most had liposarcoma (80%) and most tumors were intermediate or high grade (75%).

The median time from initial resection to LR was 23 months. The median overall survival after LR was 33 months, and the 5-year overall survival rate was 29%. Of these patients, 48% underwent resection of LR, and those patients had a median overall survival of 49 months compared with 20 months in those who did not. The 2-year overall survival rate was 73% in resected patients vs 43% in unresected patients; at 5 years, these rates were 43% and 11%, respectively (P < .0001).

Among the DM patients, the majority had leiomyosarcoma (53%), followed by liposarcoma (27%); again, most had intermediate- or high-grade tumors (93%). The median time from initial resection to DM was 12 months. Following DM, the median overall survival was 25 months and the 5-year overall survival rate was 20%.

Again, resection of the recurrence was associated with improved outcomes. A total of 53 DM patients (36%) underwent resection, and they had a median overall survival of 29 months compared with 21 months in those who did not undergo resection. The 2-year overall survival rate was 65% compared with 43%, and the 5-year overall survival rate was 34% vs 11% (P = .008).

Though the same trend regarding secondary resection appeared in the LR + DM group, the numbers were too small and the researchers did not perform multivariate analyses. In both LR and DM patients, time interval to recurrence was a significant predictor of survival; histologic subtype approached significance in LR patients, and was a significant predictor in DM patients.

“Acknolwedging the limitations of a retrospective study, our results support a role for resection of locally recurrent or distant metastatic disease in carefully selected patients, while highlighting the poor prognosis associated with recurrence of RPS, whether or not the patient undergoes resection,” the authors concluded.