(P 084) PROGNOSTIC FACTORS IN PATIENTS WITH DISTANT SOFT TISSUE METASTASIS OF CARCINOMA

Objective: Metastases from carcinomas usually present at regional lymph nodes and other organs including the liver and lung, and soft tissue metastasis (STM) is an uncommon condition in carcinoma. Although various case reports and series have been reported with regard to STM of cancer, large-scale studies are lacking. In addition, most of the previous reports have only considered their clinical trends and diagnostic methods to distinguish them from soft tissue sarcoma, and few reports have examined prognostic factors. This study aimed to evaluate the characteristics of STM and the factors affecting its prognosis.

Methods: This retrospective study enrolled patients with STM from carcinoma, and 16 consecutive patients who had sufficient medical records were included. Those with distant metastases that developed in the subcutaneous tissue or skeletal muscle were included, while those with needle tract metastases after biopsy, metastases to reactive area around wounds exposed at the time of primary tumor excision, and direct extension from adjacent tumors were excluded. The patients’ information, including age, sex, primary tumor, metastasis location, size of the metastasis tumor, presence of pain, histological classification, history of primary tumor treatment, other metastasis at diagnosis of STM, follow-up period, and outcomes, were collected. We examined the factors that may affect prognosis and compared their predictive value for prognosis.

Results: Overall, 16 patients with a mean age of 68.7 years were evaluated. The overall survival rate was not significantly different between lung and non-lung cancer patients. The overall survival rate was significantly better in patients undergoing definitive treatment for the primary tumor than in those without history of treatment (p=0.046). The overall survival rate of STM patients with no metastasis was significantly better than those with other metastasis at the diagnosis of STM (p=0.041). On multivariate analysis, no history of primary tumor treatment and STM without pain were risk factors for prognosis (p=0.0340 and 0.0474). None of the patients who developed STM under the skin experienced pain, while 92.3% of patients who developed STM in the deep layer had pain.

Conclusion: In STM cases, no past treatment of the primary tumor and absence of pain were risk factors for poor prognosis. In addition, STM in the deep layer, such as the intramuscular or intermuscular layers, is prone to pain.





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