Pandemic driven preoperative moderate hypofractionated radiotherapy for soft tissue sarcomas.

Purpose: Moderate hypofractionation was adopted to reduce hospital visits during the COVID-19 pandemic aiming to maintain treatment efficacy for soft tissue sarcoma (STS) patients, shifting preoperative schedules from 25 fractions of 2 Gy to 14-15 fractions of 3 Gy. This study evaluates the clinical implications and outcomes of this schedule, focusing on wound complications, radiation toxicity, local tumour control, and distant metastases.

Patients and methods: Data was collected from patients treated between 01 and 01-2020 and 31-12-2023. Outcomes included wound complications within 120 days post-surgery, local-recurrence, distant metastases and radiation toxicity. Logistic regression was performed to identify factors associated with wound complications. The cumulative incidence of local recurrence and distant metastases were estimated with a competing risk model.

Results: Sixty-six patients were analysed, with a mean age of 74 years (standard deviation (SD)± 11). Tumours were mainly localized in the lower extremities (64 %), mean size 103 mm (SD±58). Median follow-up was 29 months (range 2-50). A R0 resection margin was achieved in 77 % of the operated patients. The wound complication rate was 33 %, with moderate complications in 13 patients and severe in 6. The cumulative incidences of local recurrence and distant metastases at 2 years were 7.6 % (standard error (SE) 3.7 %) and 29 % (SE 6 %, Fig. 1) respectively. Acute grade 3 dermatitis occurred in one patient (1.5 %)and two patients experienced late grade 3 toxicity (fractures, 3.0 %). Twenty patients developed distant metastases, two diagnosed before start of the treatment. Eighteen patients died, with six deaths from distant metastases and one from the primary tumour.

Conclusion: Preoperative moderate hypofractionation for STS during COVID-19 showed promising results, with no increase in postoperative wound complications and favourable local failure rates.