Surgical resection of the primary lesion for osteosarcoma patients with metastasis at initial diagnosis

Background Approximately 10–20% of osteosarcoma patients present with metastasis on diagnosis. Completely resecting the lesion is associated with better prognosis. However, evidence regarding optimal surgical strategies for patients with unresectable metastasis is limited. Methods This retrospective analysis was based on the Japanese Nationwide Bone and Soft Tissue Tumor registry. In total, 335 patients diagnosed with osteosarcoma with metastasis were included. Factors affecting overall survival were identified using multivariate analysis. Kaplan–Meier method was used to compare the overall survival by the status of surgical intervention. Two hundred and four patients who did not undergo surgery for metastasis were divided into two groups, depending on whether they underwent surgery for the primary lesion. The background differences between these two groups were adjusted with propensity score matching, with 43 patients per group. The overall survival was calculated using the Kaplan–Meier method and compared with a log-rank test. Results Factors positively impacting overall survival were age <40, female sex, extremity origin, surgery for the primary lesions, surgery for metastasis and radiotherapy without surgery. For patients with unresectable metastasis, after propensity score matching, the survival rate was higher in the group that underwent primary lesion surgery than the group without surgery. Their median survival was 19 (95% confidence interval: 11.7–26.3) and 11 months (95% confidence interval: 4.5–17.5) (P = 0.02), respectively. Conclusions Surgical resection of the primary osteosarcoma lesion did not worsen prognosis, even in patients with unresectable metastasis. Further study is needed to identify which patient group will benefit from primary lesion resection.

Clinical significance of surgical treatment for imatinib-resistant gastrointestinal stromal tumors.

189 Background: The standard first-line treatment for unresectable metastasis or recurrence gastrointestinal stromal tumors (GIST) is imatinib mesylate(IM), a selective tyrosine kinase inhibitor. Although IM has markedly improved the prognosis of patients with advanced GIST, half of the patients experience tumor progression within two years because of resistance to IM. And IM-resistant GIST is basically treated by other kind of TKI, in addition, surgical treatment can be considered as one of treatment options. The aim of this study was to clarify the significance of surgical treatment for IM-resistant GIST in the era of second-line TKI treatment. Methods: We retrospectively analyzed consecutive 35 GIST patients who have developed IM-resistance between 2004 and 2015. We assessed clinicopathological characteristics, postoperative outcomes, imatinib-failure free survival(IFFS), and overall survival(OS) in patients who underwent surgical resection for the IM-resistant lesions. Results: The study enrolled 24 male patients and 11 female patients. The median [range] age was 61 [39-83] years. The primary sites were stomach / small intestine / duodenum: 16 / 14 / 5 cases and resection for primary sites was performed in 32 cases. The median [range] period of IM administration until resistance was 26 [2-119] months, and the resistant lesion sites were liver / peritoneum / primary lesion / local recurrence / bone: 17 / 18 / 2 / 1 / 1 cases (with duplication). Resection for resistant lesions was performed in 18 cases (51%), of which 13 cases (72%) underwent R0 / 1 resection. The postoperative complications ( > Clavien-Dindo classification Grade II) were observed in 3 patients: Biliary leakage, abdominal abscess, and diaphragmatic hernia. IM was resumed promptly after surgery in all 18 patients who underwent resection for IM-resistant lesions, and the median [range] period of IM administration was 22.2 [0.9-56] months. In 5 cases, multiple surgical treatments were performed and second-line TKI was administered in all except for two patients who have still been treated as IM. The median OS was 49 months. Conclusions: It was suggested that surgical treatment for IM-resistant GIST may be safe and effective for appropriate cases.