Definition: agents that selectively protect normal tissues without shielding tumor.

Examples

• Amifostine: scavenges free radicals; reduces xerostomia in head & neck RT.

• Palifermin: keratinocyte growth factor; reduces mucositis.

• Statins/ACE inhibitors: under study for fibrosis reduction.

Timing is critical

• Must be given before or during RT to protect normal tissue.

• Risk: if tumor is also protected, efficacy drops.