(P 471) IMPACT OF PRIMARY TUMOR RESECTION ON METASTASIS TO THE LUNG IN PATIENTS WITH BONE AND SOFT-TISSUE SARCOMA

Objective: The presence of distant metastases, particularly in the lungs, strongly influences prognosis in patients with bone and soft-tissue sarcomas. Chemotherapy is commonly used in patients with bone and soft-tissue sarcomas with lung metastases, and the primary tumor is not aggressively resected in these patients. However, if the primary tumor interferes significantly with the patient’s quality of life in terms of pain, neuropathy, and breaking of the skin, resection or even amputation may be required. Very few reports have investigated the effect of primary tumor resection on the prognosis of patients with bone and soft-tissue sarcomas with distant metastases. Furthermore, no reports have examined how excision of the primary tumor affects metastasis to the lungs. Therefore, we evaluated the impact of primary tumor resection on lung metastasis and prognosis in patients with bone and soft-tissue sarcoma.

Methods: We retrospectively identified 48 patients with bone and soft-tissue sarcoma involving the extremities or trunk with lung metastasis at the first visit treated at our two hospitals. Patients with lung metastasis confirmed at the same time as local primary tumor recurrence were also included. Since we aimed to assess the impact of primary tumor treatment, those who did not receive radiotherapy or surgical treatment for lung metastasis were also included. Patients’ records were searched to collect data regarding age, sex, malignancy and histological subtype, anatomical tumor location, size, lung and other metastasis, primary tumor treatment, follow-up period, and outcomes. The maximum diameter and the number of lung metastases at the first visit were evaluated. In addition, the maximum diameter of lung-metastatic lesions in each of the first and last chest computed tomography images were measured, and the average rate of increase per month (mm/month) was defined. Clinical characteristics and outcomes were compared based on primary tumor resection status, and the factors affecting prognosis were examined. In addition, we evaluated the factors affecting the average rate of increase in the size of lung metastases. We were able to measure the rate of increase in size of lung metastases more than once in 39 of the patients. The mean rate was 4.08 ± 5.37 mm/month and the patients were divided into fast and slow increase groups based on this average.

Results: Surgical treatment for the primary tumor was performed in 13 patients (27.1%), and radiotherapy for the primary tumor was performed in 16 patients (33.3%). In terms of outcomes, six patients were alive with the disease and 42 patients had died because of it at the last follow-up. Patients who had their primary tumor resected had significantly smaller lung metastases at the first visit and a slower rate of increase than those who did not undergo surgical resection (p=0.0068 and p=0.0142, respectively). The multivariate analysis revealed that the maximum diameter of lung metastases and the average rate of increase were significant prognostic predictors (p=0.04 and p=0.0003, respectively), yet primary tumor resection did not affect the outcome. The Kaplan–Meier curve revealed that patients with slow-growing lung metastases had a significantly better prognosis than those with fast-growing ones (p=0.0003). Patients in the fast-growing group had a significantly larger maximum diameter of lung metastasis at the first visit (p=0.0419). The multivariate logistic regression analysis revealed that the rate of increase was significantly associated with the maximum diameter of lung metastasis at the first visit (p=0.0245) and that surgical resection of the primary tumor did not affect the rate of increase.

Conclusion: Primary tumor resection of bone and soft-tissue sarcoma in patients with lung metastasis was not shown to affect their prognosis. The primary tumor should be excised only if it is necessary to improve the patient's quality of life.