Training-oriented framework for brachytherapy treatment planning in soft tissue sarcoma

Brachytherapy remains an important component of postoperative management for soft tissue sarcoma (STS), yet variability in clinical exposure and procedural training contributes to inconsistent trainee confidence. Recent consensus guidelines from the American Brachytherapy Society (ABS) and GEC-ESTRO define standardized objectives for brachytherapy education. This technical review operationalizes the competency domains of brachytherapy treatment planning, delivery, and quality assurance, with a specific focus on interstitial STS brachytherapy. Contemporary indications for postoperative brachytherapy as monotherapy or as a boost with external beam radiation therapy are summarized, along with implant geometry principles that inform modern catheter spacing, target coverage, and homogeneity. Key elements of CT-based simulation, catheter reconstruction, target and organ-at-risk delineation, and dwell-time optimization using manual and inverse planning approaches are described. Common dose and fractionation regimens are outlined, with practical application of organ-at-risk constraints in superficial surgical beds. Procedural considerations essential for safe delivery, including implant stabilization, positioning, wound care and mitigation of displacement, are detailed. Core quality assurance and radiation safety processes, including source verification, catheter patency checks, independent parameter validation, and incident response, are reviewed. This competency-aligned framework supports structured training and promotes safe, reproducible implementation of STS brachytherapy in contemporary clinical practice.