That document estimates 120 extra cancer deaths, should the nearly-impossible flyby reentry occur. However, a better text is the Cassini Final Environmental Impact Statement, chapter 2 (http://saturn.jpl.nasa.gov/spacecraft/safety/chap2.pdf). Table 2-8 estimates 4500 deaths, assuming there is no lower limit for radiation exposure, or 15 deaths if you exclude those with under 1/1000 rem exposure.