Risk Factors of Early Distant Metastasis After Primary Tumor Treatment in Soft Tissue Sarcoma

Distant metastasis has a strong influence on prognosis in patients with soft tissue sarcoma (STS). While various risk factors have been reported for distant metastases, risk factors for distant metastases early after treatment of primary tumor have not been investigated. This study aimed to evaluate the factors of early distant metastasis after primary tumor resection in patients with STS.

We retrospectively identified patients with STS involving the extremities or trunk without any metastasis at the first visit. Data on clinical information and detailed assessment were collected. We evaluated clinical information as a risk factor for distant or lung metastases. Additionally, we evaluated risk factors for metastases in patients with distant metastases as early as 6 months after the initial resection of the primary tumor.

A total of 337 patients were included in the study. Multivariate analysis revealed that the size of the primary tumor (p=0.0011 and p=0.0167), consultation in a short period after onset (p=0.0325 and p=0.0402), histological high grade (p=0.0006 and p=0.0002), and inadequate surgical margin (p=0.0151 and p=0.0055) were significant predictors for poor prognosis for all distant and lung metastases, respectively. However, the only risk factor for early metastases within 6 months was young age (p=0.0148).

The only risk factor for early distant metastasis after primary tumor resection in patients with STS was young age, even though large tumor diameter and histological high grade were risk factors for distant metastasis.