Background: Several previous reports have described multiple cancers with regard to epithelial tumors, but few reports have focused on multiple primary malignancies including soft tissue sarcomas (STS).
Methods: The purpose of this study was to analyze the clinical features of patients with high-grade STS with multiple malignancies and possible clinical problems, compared with those with STS as a single malignancy, focusing on elderly patients. This study enrolled 107 patients aged 65 years or over with high-grade STS.
Results: Eighty-four patients (79 %) had sarcomas only (S group), and 23 (21 %) had multiple primary malignancies (M group). STS preceded carcinoma in 10 patients, and carcinoma preceded STS in 13. In 7 patients (30 %), the interval between the first and second malignancy was less than a year. Of 7 patients who received treatment for sarcoma and carcinoma at the same time, the presence of other malignancies had an impact on determination of the treatment modality in 5 patients. The overall survival rate at 5 years was higher in M group (79 %) than in S group (69 %), although this difference was not significant (P = 0.095).
Conclusions: This study demonstrates that the presence of multiple malignancies was not correlated with a poor prognosis, and was actually associated with a better prognosis in elderly patients with STS. Physicians should be aware of the possible occurrence of a second malignancy, and on occasion the treatment modalities and their logistical aspects need to be well organized and carefully selected for patients with ongoing multiple malignancies.