Recent progress in cancer treatment has improved patient survival, but has increased the number of patients with metastatic bone tumors. Data were collected from all bone metastasis patients at Kagoshima University, where almost all patients with metastatic bone tumors who reside in Kagoshima province are treated surgically. The scoring systems used in bone metastasis patients were then evaluated to identify those most suitable for our patients. Clinical data were collected from 145 patients with bone metastases. The patients were assigned prognostic scores based on four scoring systems, namely those described by the Ratasvuori, Mizumoto, Tokuhashi and Katagiri groups. Statistical examinations were performed to assess patient distribution regarding prognostic factors and the four data sets reported in the literature. The patient distributions for all prognostic factors were significantly different between the Scandinavian Sarcoma Group (SSG) and Kagoshima data. The distributions of patients for 3 of 5 and for 5 of 7 prognostic factors were statistically different between the Kagoshima data and the Katagiri and Tokuhashi data, respectively. Additionally, the distribution of patients in each scoring group was statistically different between the Kagoshima data and the Katagiri, Tokuhashi and Mizumoto data. The predictions of prognosis were significantly different between the results of each group and ours. The Tokuhashi scoring system detected the highest survival at 6 months (88.8%) in the Kagoshima data. Patients with a life expectancy of >6 months benefited from tumor excision and reconstruction. These findings suggest that the Tokuhashi scoring system is the most suitable for identifying patients who should be assessed for curative surgical intervention. SSG scoring, however, was suitable for identifying patients expected to survive for <6 months (91.3%). Prior to selecting a scoring system to predict prognosis, it is important to determine which scoring system is the most appropriate, based on each hospital's particular characteristics.
Keywords: metastatic bone tumor; performance status; prognosis; prognostic factor; scoring.