Prognostic factors of metastatic myxoid liposarcoma

Abstract

Background: Myxoid liposarcoma (MLS) has the tendency to metastasize extrapulmonary. Although prognostic factors at the initial diagnosis of MLS have been reported, those at diagnosis of metastasis remain unclear. The purpose of this study was to investigate the prognostic factors for disease-specific survival at the initial diagnosis of metastasis.

Methods: This retrospective observational study was conducted at three cancer centers and two university hospitals in Japan. Of 274 MLS patients pathologically diagnosed between 2001 and 2015, 48 metastatic patients were examined.

Results: Lung metastases were detected in nine patients (18.8%) and extrapulmonary metastases in 45 (93.8%). Interval from primary diagnosis to the first metastasis was significantly shorter in patients with lung metastases than without (p = 0.007). Median disease-specific survival after diagnosis of metastases was 52.5 months in all patients. In multivariable analysis, liver metastasis (hazard ratio (HR), 2.71 [95% confidence interval (CI), 1.00-7.09]) and no evidence of disease (NED) achieved by radical treatment (resection with or without radiation therapy, or radiation therapy ≥60 Gy) or semi-radical (radiation therapy ≥40 Gy) treatment were significantly related to survival (HR, 0.36; 95%CI [0.13-0.95]). The number of metastases (odds ratio (OR), 0.44; 95%CI [0.25-0.78]) and abdominal/retroperitoneal metastases (OR, 0.09; 95%CI [0.008-0.95]) were the significant inhibitory factors of achieving NED.

Conclusions: This is the first study to statistically demonstrate the importance of achieving NED with surgical resection or radiation therapy for longer survival in metastatic MLS patients. As number of metastases was a significant factor for achieving NED, early detection of metastases might be important.

Keywords: Metastasis; Myxoid liposarcoma; Prognostic factor.

Fig. 1

Time to metastasis from the primary diagnosis. a M0 patients (n = 34), b all patients with or without pulmonary metastases (n = 48). a Twenty-eight patients (82.4%) developed metastasis within 4 years and 31 patients (91.2%) within 8 years. Only three patients (8.8%) developed metastasis after 8 years of follow-up. b “with lung metastasis” means the presence of lung metastasis with or without metastasis in another location, and “without lung metastasis” means absence of lung metastasis at the initial diagnosis of metastasis. In patients “with lung metastases”, five out of 9 patients (55.6%) had metastasis at the initial diagnosis of primary MLS, and all patients were diagnosed to have metastasis within 2 years, which was significantly shorter than in patients “without lung metastases” (15.3 months; p = 0.007)

Fig. 2

Disease-specific survival. a after the diagnosis of metastasis, (B) after the diagnosis of primary tumor. a The median disease-specific survival following the diagnosis of metastasis was 52.5 months and the 5-year survival rate was 40.6%. b The median disease specific survival following the diagnosis of the primary tumor for metastatic patients was 87.3 months and the 5-year survival rate was 56.2%

Fig. 3

Disease-specific survival after the diagnosis of metastasis by (a) Time to metastasis, (b) with or without liver metastasis, (c) NED achievement. a Time to metastasis ≥24 month, b Patients without liver metastasis, and c NED achievement were significantly related to longer disease specific survival analyzed by Kaplan-Meier method