Abstract: We included 18 studies, although we were only able to extract participant data from 14 studies that included a total of 511 participants; 419 participants were managed by intralesional treatment and 92 underwent a wide resection. We were not able to extract participant data from four studies, including 270 participants, and so we included them as a narrative summary only. The evidence was at high risk of performance, detection and reporting bias. Meta-analysis of data from 238 participants across seven studies demonstrated little or no difference in recurrence-free survival after intralesional treatment versus wide resection for central LGCS in the long bones (risk ratio (RR) 0.98; 95% confidence interval (CI) 0.92 to 1.04; very low-certainty evidence). MSTS scores were probably better after intralesional surgery (mean score 93%) versus resection (mean score 78%) with a mean difference of 12.69 (95% CI 2.82 to 22.55; P value < 0.001; 3 studies; 72 participants; low-certainty evidence). Major complications across six studies (203 participants) were lower in cases treated by intralesional treatment (5/125 cases) compared to those treated by wide resection (18/78 cases), with RR 0.23 (95% CI 0.10 to 0.55; low-certainty evidence). In four people (0.5% of total participants) a high-grade (grade 2 or dedifferentiated) tumour was found after a local recurrence. Two participants were treated with second surgery with no evidence of disease at their final follow-up and two participants (0.26% of total participants) died due to disease. Kaplan-Meier analysis of data from 115 individual participants across four studies demonstrated 96% recurrence-free survival after a maximum follow-up of 300 months after resection versus 94% recurrence-free survival after a maximum follow-up of 251 months after intralesional treatment (P value = 0.58; very low-certainty evidence). Local recurrence or metastases were not reported after 41 months in either treatment group. Only evidence of low- and very low-certainty was available for this review according to the GRADE system. Included studies were all retrospective in nature and at high risk of selection and attrition bias. Therefore, we could not determine whether wide resection is superior to intralesional treatment in terms of event-free survival and recurrence rates. However, functional outcome and complication rates are probably better after intralesional surgery compared to wide resection, although this is low-certainty evidence, considering the large effect size. Nevertheless, recurrence-free survival was excellent in both groups and a prospective RCT comparing intralesional treatment versus wide resection may be challenging for both practical and ethical reasons. Future research could instead focus on less invasive treatment strategies for these tumours by identifying predictors that help to stratify participants for surgical intervention or close observation.

Plain-language summary: We identified 14 studies that were suitable for analysis with a total of 511 participants; 92 were treated by wide resection compared to 419 by intralesional treatment. Age of the participants varied from 13 to 82 years with a mean age of 48 years. Women outnumbered men in the studies by just over one and a half times, which reflects that LGCS are more common in women. People were followed-up for between 24 to 300 months after surgery. In addition, there were four studies including 270 participants, from which we could not extract the exact data, but were used to confirm the statistical analysis. We found that there was little or no difference in rates of local recurrence between treatment types. In 94% to 96% of the cases, the tumour was successfully removed after a single operation. In the few cases where disease recurred, a second operation was needed. People with LGCS probably have better functionality after less aggressive intralesional treatment, and complication rates were probably lower compare to wide surgical resection. Less than 0.3% of all people with LGCS died due to their disease, irrespective of the surgical technique. Overall certainty of the studies was very low, as all studies only described the results of the treatment in hindsight and none of the studies randomly selected patients between treatment groups.