Computed tomography (CT) is widely used for follow-up of lung metastasis in patients due to soft tissue sarcoma (STS), the frequency of chest X-ray (CXR) is obviously reduced. This study verified the current status of diagnostic measures and the efficacy of CXR. A retrospective analysis of 18 patients that underwent surgery for lung metastasis due to STS was performed. The investigation compared the follow-up interval using CT after STS surgery, time from STS surgery to lung metastasis, tumor size of lung metastasis, detection rate with CXR, time from detection to surgery for lung metastasis, number of CT scans and follow-up interval using CT after detection of lung metastasis. The follow-up interval when using CT after STS surgery was 3.5 months (m). Time from STS surgery to lung metastasis was 34.3m. Tumor size of lung metastasis was 15 mm, and the detection rate by CXR was 66.7%. The time from detection to surgery for lung metastasis was 4.8m, the number of CT scans was 3.1, and the interval was markedly shortened to 1.6m. Follow-up should be performed by CXR if the tumor is detected by CXR. CT evaluation is required when the tumor size has increased, and prior to surgery for lung metastasis.Keywords: soft tissue sarcoma, lung metastasis, follow-up size, histological type and grade, and positive surgical margins. [4][5][6][7][8] Imaging of the chest by computed tomography (CT) and chest X-ray (CXR) is recommended regularly for detecting the presence of pulmonary metastasis after curative resection for STS.Computed tomography is widely used for follow-up of lung metastasis in patients with STS. On the other hand, the frequency of CXR is obviously reduced. The effective radiation dose from CXR is estimated to be between 0.02 mSv and 0.1 mSv, which is equivalent to between 2.4 days and 10 days of background radiation. Obviously, the overall radiation dose of CXR is smaller than that of CT. Furthermore, CT may give false positive results in the presence of small lung nodules (<5 mm).
9)Although CXR is a valid and feasible way, CT is performed without CXR.The aim of this study is to elucidate the current status of diagnostic measures for the follow-up of lung metastasis due to STS and the efficacy of CXR.