Preoperative vs postoperative radiation therapy in localized soft tissue sarcoma: Nationwide patterns of care and trends in utilization

Abstract

Purpose: The timing of perioperative radiation therapy (RT) in the treatment of soft tissue sarcoma (STS) varies among institutions. This study examines patterns of care, trends in utilization, and survival with preoperative versus postoperative RT for primary STS.

Methods and materials: Using the National Cancer Data Base, we identified patients with stage I-III STS who underwent definitive surgery with either preoperative or postoperative RT between 2004 and 2012. Univariate, bivariate, and multivariate analyses were performed to identify factors predicting receipt of preoperative versus postoperative RT. Overall survival (OS) was analyzed using the log-rank test, Kaplan-Meier method, and Cox proportional-hazards model.

Results: This study included 9604 patients: 7246 (75.4%) received postoperative and 2358 (24.6%)-preoperative RT. Chemotherapy was administered to 27.0% patients in the preoperative and 13.0% in the postoperative cohort. Use of preoperative RT increased over time, from 16.8% in 2004 to 29.7% in 2012. Multivariate analysis revealed that preoperative RT utilization increased with the following factors: higher educational attainment, treatment at an academic facility, further distance from facility (>60 miles), receipt of chemotherapy, tumor originating in lower extremities, >10 cm tumors, and myxoid liposarcoma. OS analysis revealed no difference between the 2 treatment cohorts.

Conclusions: Postoperative RT is used much more commonly than preoperative RT in localized STS; however, preoperative RT use has increased in recent years. Multiple demographic and clinicopathologic factors were predictive of preoperative RT use. Consistent with randomized phase 3 data, there was no difference in OS.

Figure 1

Exclusion criteria and treatment group allocation. RT, radiation therapy.

Figure 2

Trends in preoperative RT utilization by year of diagnosis. This figure shows that there was a significant 7.74% annual percent change (APC) increase (P = .0001) in preoperative RT utilization (APC, 7.74; 95% confidence interval, 5.58-9.94) over the study period. Overall, the use of preoperative RT increased from 16.8% in 2004 to 29.7% in 2012. Abbreviation as in Fig 1.

Figure 3

Trends in preoperative RT utilization stratified by (A) primary site and (B) tumor size. Abbreviation as in Fig 1. Abbreviations: APC = Annual Percent Change. The figure above shows the trend in preoperative RT utilization by year of diagnosis. Overall, the use of preoperative RT increased over the study period, from 16.8% in 2004 to 29.7% in 2012. For the overall cohort, there was a significant 7.74% increase (p-value = 0.0001) in preoperative RT utilization from 2004 to 2012 (APC: 7.74, 95% CI 5.58 - 9.94).

Figure 4

Adjusted Cox regression model curves