A 6-year-old has been diagnosed with Wilms tumor (nephroblastoma) involving the right kidney with no metastases (Stage I). Histopathology shows favorable histology. According to COG/SIOP staging, which is the preferred initial management approach in North America (COG protocol) vs. Europe (SIOP protocol)?

• A COG: Pre-operative chemotherapy then surgery; SIOP: Upfront surgery
• B Both COG and SIOP recommend pre-operative chemotherapy for all stages
• C COG: Immediate nephrectomy followed by adjuvant chemotherapy; SIOP: Pre-operative chemotherapy followed by delayed nephrectomy ✓
• D Both COG and SIOP recommend immediate surgery for all operable tumors

Explanation

The key difference between COG (Children's Oncology Group, North America) and SIOP (International Society of Pediatric Oncology, Europe) approaches to Wilms tumor is the timing of surgery: COG recommends immediate upfront nephrectomy followed by stage-and-histology-based adjuvant chemotherapy ± radiotherapy, as upfront surgery provides accurate pathological staging and avoids under/over-treatment. SIOP recommends pre-operative chemotherapy (neoadjuvant) to shrink the tumor before delayed nephrectomy, which reduces surgical complications and anaplasia detection bias. Both approaches yield excellent overall survival (>90% for Stage I favorable histology). This distinction is frequently tested in NEET PG.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.