"Improved outcomes with higher doses for salvage radiotherapy after prostatectomy." King, CR, and MT Spiotto. International Journal of Radiation, Biology, and Physics. 1 May 2008, 71(1):23-7. http://www.ncbi.nlm.nih.gov/pubmed/18207668
"PURPOSE: To evaluate relapse-free survival with higher doses for patients receiving salvage radiotherapy (RT) after radical prostatectomy (RP). PATIENTS AND METHODS: A total of 122 patients with pathologically negative lymph nodes received salvage RT after RP from 1984 to 2004...CONCLUSIONS: A clinically significant dose response from 60 Gy to 70 Gy was observed in the setting of salvage RT after prostatectomy. A dose of 70 Gy to the prostate bed is recommended to achieve optimal disease-free survival."