A teenage boy with confirmed osteosarcoma of the distal femur undergoes neoadjuvant chemotherapy followed by wide resection. Histological analysis of the resected specimen reveals 95% tumor necrosis. This finding indicates:

• A Poor response to chemotherapy; regimen should be changed
• B Good response (Huvos Grade III–IV); prognosis is favourable ✓
• C Pathological complete response requiring no adjuvant treatment
• D Inadequate surgical margins regardless of tumor necrosis

Explanation

Huvos grading assesses histological response to neoadjuvant chemotherapy in osteosarcoma: Grade I (<50% necrosis), Grade II (50–89%), Grade III (90–99%), Grade IV (100% necrosis). Necrosis ≥90% (Huvos III or IV) is considered a good response and is the single most important prognostic factor for event-free survival, with 5-year survival exceeding 70–80%. Poor responders (<90% necrosis) are switched to salvage regimens in some protocols though benefit is debated.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.