Prognostic Analysis Of Osteosarcoma Based On The Preoperative Imaging Assessment And Surgical Margin

Osteosarcoma is a malignant bone tumor derived from mesenchyme.The malignant cells are characterized by the production of osteoid tissue or immature bone.The 5-year survival in patients with osteosarcoma was less than 20% in the 1950 s.With the combination of multi-drug neoadjuvant chemotherapy and surgical resection,the 5-year overall survival(OS)rate has increased to 60–70%.The current treatment guidelines provide the principles of surgery,which are similar to the Enneking staging system proposed in 1980.The guidelines require a resection with at least a wide margin.Wide and radical margins are regarded as adequate margins,while intralesional and marginal margins are regarded as inadequate margins.Neoadjuvant chemotherapy was not yet widely used in that era.With the development of chemotherapy,there is inconsistent for the application of marginal margin in limb-salvage surgery(LSS).Recent studies showed that the likelihood of increasing local recurrence(LR)is associated with margin status rather than margin width.It is still unclear whether the marginal margin increases the risk of LR and whether the effect of chemotherapy affects the safety of a narrow surgical margin.Section I [Purpose] There are conflicting findings about the effect of resection margins on LR in osteosarcoma after surgery.In this systematic review,we examined the association between LR and resection margins for osteosarcoma in extremity and pelvis.[Methods] EMBase,PubMed and Cochrane CENTRAL were searched from January 1980 to July 2016.The quality of included studies was evaluated using the NewcastleOttawa Quality Assessment Scale.The odds ratio and 95% confidence interval of LR were estimated,respectively,for inadequate vs adequate margins and marginal vs wide margins using a random-effect model.Chi-square test was performed to comparing the LR rate between extremity and pelvic osteosarcomas with an identical surgical margin.[Results] Thirteen articles involving 1559 patients(175 with and 1384 without local recurrence)were included in this study.The meta-analysis showed that the osteosarcoma resected with inadequate and marginal margins,whether in extremity or in pelvis,were associated with a significantly higher LR rate than the osteosarcoma resected with adequate and wide margins,respectively.Chi-square test showed that,when pelvic and extremity osteosarcomas were removed with an identical resection margin,the LR was significantly more frequent in pelvis osteosarcoma than in extremity osteosarcoma.[Conclusions] This study provides level IIa evidence to support that the surgery with adequate or wide resection margin has positive effect on reducing the risk LR in osteosarcoma.In addition,the factors independent of resection margin are more likely to increase the risk of LR in pelvic osteosarcoma.Section II [Purpose] The method used to evaluate the response of osteosarcoma to preoperative chemotherapy before specimen resection is still unclear.The purpose of this study was to identify factors that contribute to OS and to discuss their roles in making a decision regarding surgical margins.[Methods] Patients(109)with pathologically confirmed Enneking IIB osteosarcoma were retrospectively analyzed.Univariate and multivariate survival analyses were performed.Patient characteristics and chemotherapy-induced contrast-enhanced MRI changes were considered as potential factors.[Results] Changes in the tumor volume and the relative necrosis ratio measured by MRI were independent risk factors predicting the OS of patients who underwent limbsalvage surgery.For those in whom the tumor volume had decreased(VolRatio<1)or the relative necrosis ratio had increased by at least 10%(NecRatioInc?0.1),there was no significant difference in OS between wide and marginal margins.[Conclusions] Variables measured by contrast-enhanced MRI could be used to evaluate chemotherapy response and increase the limb-salvage rate.