Main Session
Sep
28
PQA 04 - Breast Cancer, Patient Reported Outcomes/QoL/Survivorship, Functional Radiation Medicine, Hematologic Malignancies, Palliative Care, and International/Global Oncology
2687 - Outcomes of Adjuvant Radiotherapy for Pigmented Villonodular Synovitis: A Single-Institution Experience
Presenter(s)
Majd Alotaibi, MD - Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON
M. Alotaibi1, D. Al-Bukhari2, M. F. F. Alhakami3, and I. S. Alomary3; 1King Abdulaziz University, Jeddah 21452, Saudi Arabia, 2Ministry of National Guard Health Affairs, Jeddah, Saudi Arabia, 3King Abdulaziz Medical City PNOC, Jeddah, Saudi Arabia
Purpose/Objective(s):
Pigmented villonodular synovitis (PVNS) of the knee is a rare but locally aggressive synovial disorder with substantial postoperative recurrence risk. Although adjuvant radiotherapy has been used for decades, functional outcome data remain limited. We hypothesized that postoperative external beam radiotherapy (EBRT) following surgical resection of PVNS of the knee is associated with improved local control, while maintaining long-term knee function as measured by WOMAC score. The primary objective was to determine the rate of local control and functional outcomes after EBRT.Materials/Methods:
We performed a retrospective review of patients with biopsy-confirmed PVNS of the knee treated with adjuvant EBRT at a single institution between 2014 and 2024. Patients received postoperative external beam radiotherapy to a median dose of 35 Gy (range 34–36 Gy), delivered in 14–18 fractions using three-dimensional conformal radiotherapy (3DCRT). Local control (LC) was defined as no clinical or radiologic evidence of recurrence, or stable residual disease, for at least 1 year following RT. Functional outcomes were assessed using the validated Arabic version of the reduced Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), scored from 0-100, with higher scores indicating less disability. Treatment-related toxicity was evaluated through medical record review. Associations between clinical variables and WOMAC scores were explored using Mann-Whitney testing and Spearman correlation analysis. A p-value <0.05 was considered statistically significant.Results:
Eleven patients met inclusion criteria. Median age at presentation was 34.7 years (range 15-50), and 81.8% were male. Arthroscopic resection was the most common surgical approach (72.7%), and the majority of patients (81.8%) had gross residual disease prior to radiotherapy. Median follow-up was 46.5 months (range 3-135). Local control was observed in 10 of 11 patients (90.9%), with one documented recurrence (9.1%). No acute or late radiation-related toxicities were identified. Lymphedema was noted in two patients (18.2%), and no patient reported clinically significant functional deterioration attributable to radiotherapy. WOMAC data were available for nine patients. The median score was 18 (IQR 14-36.5), consistent with overall favorable functional outcomes. Longer interval from EBRT to WOMAC assessment was associated with improved functional scores (Spearman r=0.763, p=0.017). No other variables demonstrated a significant association with functional outcome.Conclusion:
Adjuvant EBRT following surgical management of PVNS of the knee was associated with high rates of local disease control and preserved long-term function as measured by WOMAC score. These findings support consideration of postoperative radiotherapy in patients with PVNS disease. Multi-institutional studies with larger cohorts are needed to further clarify optimal patient selection and treatment parameters.