Regarding the management and behavior of giant cell tumor of bone, all of the following statements are correct EXCEPT:

Explanation

## Management, Prognosis, and Complications of Giant Cell Tumor ### Treatment Principles **Key Point:** Curettage with adjuvant therapy is the gold standard for GCT, aiming to preserve joint function while minimizing recurrence. Radiotherapy is reserved for inoperable cases or recurrent disease. #### Primary Treatment: Curettage + Adjuvant - **Intralesional curettage** — removes tumor while preserving bone and joint architecture - **Adjuvant methods** to reduce recurrence: - Phenol (chemical cauterization) - Liquid nitrogen (cryotherapy) - Polymethylmethacrylate (PMMA) cement - High-speed burring - Recurrence rates: **10–20%** with adjuvant therapy; **40–65%** with curettage alone #### Role of Radiotherapy - **NOT first-line** — reserved for: - Inoperable or inaccessible tumors - Recurrent disease unfit for re-surgery - Palliation - **Recurrence rates with radiotherapy alone: 25–50%** — better than curettage alone but inferior to curettage + adjuvant - **Risk of malignant transformation** increases with radiotherapy ### Metastatic Behavior **High-Yield:** GCT is benign but can metastasize — a unique paradox. - **Pulmonary metastases:** 1–5% of cases - Usually occur from: - Recurrent primary tumors - Incompletely excised lesions - Rarely, from benign primary ("benign metastasizing GCT") - Metastases may regress spontaneously or remain indolent ### Malignant Transformation - **Rare but documented** complication - Occurs in 1–5% of cases - Risk factors: - **Radiotherapy** (major risk factor) - Recurrent disease - Long-standing tumor - Malignancies: osteosarcoma, fibrosarcoma, giant cell sarcoma ### Why Radiotherapy Alone Is Suboptimal | Feature | Curettage + Adjuvant | Radiotherapy Alone | Wide Excision | |---------|----------------------|-------------------|---------------| | Recurrence rate | 10–20% | 25–50% | <5% | | Joint preservation | Excellent | Good | Poor | | Malignant transformation risk | Minimal | Increased | Minimal | | Functional outcome | Superior | Good | Limited | **Warning:** The statement "recurrence rates are highest (>50%) with radiotherapy alone" is MISLEADING. While radiotherapy alone has recurrence rates of 25–50%, curettage alone (without adjuvant) has recurrence rates of 40–65%, which is actually higher. The question stem implies radiotherapy has the highest recurrence rate, which is incorrect. **Clinical Pearl:** Modern practice favors curettage + adjuvant over radiotherapy for primary GCT because it preserves joint function and has lower malignant transformation risk, despite slightly higher recurrence rates than wide excision. [cite:Robbins 10e Ch 26; Canale & Beaty Orthopaedic Surgery 13e]