Detrimental effect of COVID-19 pandemic on patients with extremity bone sarcoma. Reference center experience

1 BACKGROUND: COVID-19 pandemic had a major impact on the healthcare system globally. This work aims to evaluate COVID-19 impact on local treatment in bone sarcoma treated in a single, high-throughput institution. 2 METHODS: We have analyzed the local outcomes (i.e., possibility of limb sparing surgery) in all bone sarcoma patients treated between January 2016 and November 2022 in the main sarcoma reference center in Poland. Patients treated in the 2016-2019 period were regarded as "pre-pandemic" group, patients treated in 2020-2022 - "pandemic". Mann-Whitney U and Chi-square tests were used in the statistical analysis. No correction for multiple testing was applied. Tests with p < 0.05 were deemed significant. 3 RESULTS: There were 302 eligible patients identified. The group characteristics are presented in table 1. There were no differences in patient-related variables and histological subtypes of tumors between two groups. The tumor size did not differ (p = 0.053), when all tumor grades were considered, but high grade tumors were larger in the "pandemic" group (p = 0.034). This was reflected in the percentage of limb sparing surgeries which dropped from 83.3 % to 68.2 % ("pre-pandemic" vs. "pandemic", p = 0.004). This difference was even more stark in case of high grade tumors - 78 % vs. 54 % respectively (p = 0.001). 4 CONCLUSION: To our knowledge, this is the first report of the long lasting impact of COVID-19 pandemic on oncologic treatment outcomes in patients with malignant bone tumors.