Giuliani had radiation therapy.
http://www.nydailynews.com/news/politics/2007/12/23/2007-12-23_cancer_test_for_rudy_giuliani.html
Power of the pellets
When Rudy Giuliani was diagnosed with prostate cancer back in 2000, he had to undergo nine months of therapy.
First he received injections of Lupron, a drug that stops testosterone — which feeds the cancer — and helps shrink the prostate. The drug was administered monthly throughout his treatment.
Next, doctors implanted 90 rice-sized titanium pellets into the prostate, designed to kill the cancer cells.
The last stage — the most arduous — was five weeks of daily external beam radiation.
Guiliani’s treatment was controversial because surgery is the usual option for men under 60 with early cancer. The mayor was 55.
See #105. Rudy only missed a couple days of work.