Second cancers in children treated with modern radiotherapy techniques

Area of Science:

• Radiation oncology
• Medical physics
• Pediatric oncology

Background:

• Scattered radiation in radiotherapy may pose a higher risk of secondary cancers in children compared to adults.
• Advanced techniques like intensity-modulated radiation therapy (IMRT) and passive proton therapy could potentially increase secondary cancer incidence.

Purpose of the Study:

• To estimate the secondary cancer risk associated with modern radiotherapy techniques.
• To compare these risks between an adult prostate cancer patient and a child with rhabdomyosarcoma of the prostate.

Main Methods:

• Utilized the organ equivalent dose (OED) concept with varying dose-response models.
• Planned conformal radiotherapy, IMRT (6MV photons), and proton therapy for both patient types.
• Estimated OED for the whole body, rectum, and bladder, calculating relative cumulative risk.

Main Results:

• In adults, secondary cancer risk increased slightly with IMRT or passive proton therapy compared to conventional planning, not exceeding 15%.
• In children, proton therapy maintained or reduced secondary cancer risk.
• The cumulative risk in children relative to adults could be substantial (10-15 times higher).

Conclusions:

• Modern radiotherapy techniques, including IMRT and proton therapy (active and passive), do not elevate the risk of secondary cancers.
• Comparison between adult and pediatric prostate cancer treatment shows comparable or reduced risks with advanced techniques.