Background: Soft tissue sarcomas (STS) are rare mesenchymal neoplasms with a variety of histological subtypes. However, in Japan, data on the clinical characteristics and prognostic profiles of these tumors are lacking. The purpose of the present study was to clarify the clinical features and outcomes of Japanese patients with retroperitoneal and abdominal STS.
Methods: We reviewed and analyzed retrospectively the data for 82 patients who underwent surgery for retroperitoneal and abdominal STS at Osaka University and affiliated hospitals from 2000 to 2007. The factors analyzed included patient demographics and clinical features.
Results: The histological subtypes included leiomyosarcoma in 32 patients (39.0%), liposarcoma in 30 (36.6%), malignant fibrous histiocytoma in 10 (12.2%), and other miscellaneous subtypes in 10 (12.2%). The overall survivals were 92, 69, and 62%, respectively, at 1, 3, and 5 years after primary surgery. The overall survival of patients with low-grade sarcoma was significantly better than that of patients with high-grade sarcoma. Complete resection was done in 63 patients (77%) and their recurrence-free survivals were 73, 34, and 23%, respectively, at 1, 3, and 5 years after the surgery. Subgroup analysis of differences between leiomyosarcoma and liposarcoma revealed that liposarcomas were mainly located in the retroperitoneum and leiomyosarcomas were located equally in the retroperitoneum and abdominal cavity. The tumor size of liposarcomas was larger than that of leiomyosarcomas; however, the recurrence-free survival was better in patients with liposarcoma than in those with leiomyosarcoma.
Conclusion: Our results showed the clinical features and prognoses of retroperitoneal and abdominal STS in Japan. Further large-scale nationwide studies are required to clarify the detailed clinical behavior of retroperitoneal and abdominal STS in Japan.