The Impact of Perioperative Radiotherapy on Disease-Specific Survival in Patients with Localized Retroperitoneal Liposarcoma: A Population-Based Propensity-Score Matched Analysis.

BACKGROUND

The impact of radiotherapy on the oncologic outcome of retroperitoneal liposarcoma (RPLS) remains controversial. The aim of this study was to evaluate the effect of radiotherapy on disease-specific survival (DSS) in a cohort of patients with RPLSs.

METHODS

In this population-based, retrospective cohort study, patients with localized RPLSs who underwent surgical therapy were identified from the Surveillance, Epidemiology, and End Results-17 cancer registry program. After propensity-score matching for potential confounders, multivariable logistic and Cox regression analyses were used to examine factors associated with DSS and radiotherapy.

RESULTS

From 2004 to 2020, 1692 patients with localized RPLS who underwent surgical therapy were identified (84.2%  White, 44.6% female, mean age 62 years). Of those patients, 393 patients (23.2%) received perioperative radiotherapy. Patients who received radiotherapy had a higher rate of tumor size between 10 and 20 cm and unknown tumor grading. After propensity-score matching, multivariable adjusted Cox regression and Kaplan-Meier survival analysis demonstrated no improvement of DSS for patients who underwent radiotherapy (hazard ratio 1.04, confidence interval 0.81-1.32; log-rank p = 0.47). Patient age ≥80 years, larger tumor size, and tumor grading G3 versus G1/2 were associated with an increased risk of death due to RPLS. Subgroup analyses stratified by grading showed similar outcomes.

CONCLUSIONS

The administration of perioperative radiotherapy did not improve DSS in patients undergoing surgery for localized RPLS in this population-based study. Therefore, the use of perioperative radiotherapy in these patients may be questioned. However, the findings should be interpreted with caution due to the inherent limitations of the Surveillance, Epidemiology, and End Results (SEER) database.