Osteosarcoma most commonly occurs in patients younger than 30 years old. Which option best describes this peak incidence?

• A. Under 30
• B. 30-40
• C. 40-50
• D. 50-60

Answer: (A)

Osteosarcoma is most tied to periods of rapid bone growth, which occur during adolescence. The cells in growing metaphyseal regions (the ends of long bones like the distal femur and proximal tibia) are highly active, and this surge in osteoblastic activity carries an increased risk of malignant transformation. This is why the highest incidence is in the teenage years, typically well under 30. While there is a smaller second peak later in life in settings such as Paget disease or after irradiation, the dominant pattern is adolescence, so describing the peak as under 30 best captures the common age range.