Contemporary indications for neoadjuvant chemotherapy for conventional osteosarcoma: results from a survey of South African surgeons and onco

Abstract

Background: This study describes the contemporary approach to using neoadjuvant chemotherapy (NACT) in high-grade conventional osteosarcoma (COS) of the extremities in South African clinical practice. Secondarily, we determine if any factors were associated with routinely using NACT.

Methods: A cross-sectional questionnaire-based online survey was performed involving orthopaedic oncology surgeons and medical oncologists working in South Africa on the indications and use of NACT in COS. For statistical analysis, we employed Stata Version 18 and GraphPad Prism analysis to generate descriptive statistics and encode open-ended responses. We used chi-square or Fisher’s exact association tests to summarise variables with medians and percentages. Univariate and multivariate logistic regression assessed associations with NACT use in COS, with significance at p < 0.05. The reliability of the survey scale was Cronbach’s alpha coefficient (0.6409).

Results: NACT was routinely prescribed by 69% of all respondents. Orthopaedic surgeons were less likely to recommend the use of NACT than oncologists (odds ratio [OR] 0.16; 95% confidence interval [CI] 0.02 to 0.95; p = 0.044). Notably, orthopaedic surgeons were also more likely to treat a high volume of COS cases per annum (OR 0.02; CI 0.002 to 0.25; p < 0.001). Regarding NACT administration without limb salvage, orthopaedic surgeons were less likely to prescribe NACT prior to amputation surgery than oncologists (OR 0.11; CI 0.02 to 0.73; p = 0.041). A public practice clinical setting was associated with worse outcomes regarding disease progression (DP) on NACT (OR +infinity; CI 1.364 to +infinity; p < 0.043) and NACT response rate < 50% (OR 18.33; CI 2.51 to 102.5; p = 0.005).

Conclusion: In South African clinical practice, we observed disparities in the approach to treating highgrade conventional osteosarcomas of the extremities among clinicians regarding the use of neoadjuvant chemotherapy. This further elucidates the need for more data pertaining to COS in South Africa to enable the development of pragmatic treatment guidelines tailored to our context to improve outcomes.

Level of evidence: 5