What SBRT dose would you give to a single external iliac lymph node recurrence (1 cm size) for a patient previously treated with salvage radiation to the pelvis?

35 Gy/5 is fairly safe in the re-irradiation setting, and in our experience, it's quite effective for nodal disease.

Usually, 7 to 8 Gy x 5 to PTV and 8 to 9 Gy x 5 to GTV, based on OAR dose.

This is clearly an issue that is becoming more common, especially with PSMA scans.

Several points are needed and have been mentioned:

1. Previous dose/fractionation scheme
2. Time since previous treatment
3. Technique and dose to the small bowel

We now have about 10 patients treated for this issue and have...

Usually 7 to 8 Gy x 5 to PTV and 8 to 9 Gy x 5 to GTV based on OARs.