US News & World Reports: Top US Cancer Hospitals

With their 2009 rankings coming out soon, here's US News & World Report's 2008 ranking of the best cancer hospitals in the US, which includes 170 hospitals nationwide, the top 20 of which are below:

1 University of Texas MD Anderson Cancer Center, Houston TX
2 Memorial Sloan-Kettering Cancer Center, New York NY
3 Johns Hopkins Hospital, Baltimore MD
4 Mayo Clinic, Rochester MN
5 Dana-Farber Cancer Institute, Boston MA
6 University of Washington Medical Center, Seattle WA
7 Massachusetts General Hospital, Boston MA
8 University of California, San Francisco Medical Center, San Francisco CA
9 Stanford Hospital and Clinics, Stanford CA
10 Ronald Reagan UCLA Medical Center , Los Angeles CA
11 Duke University Medical Center, Durham NC
12 Hospital of the University of Pennsylvania, Philadelphia PA
13 Cleveland Clinic, Cleveland OH
14 Vanderbilt University Medical Center, Nashville TN
15 Fox Chase Cancer Center, Philadelphia PA
16 H. Lee Moffitt Cancer Center and Research Institute, Tampa FL
17 University of Michigan Hospitals and Health Centers, Ann Arbor MI
18 University of Chicago Medical Center, Chicago IL
19 Ohio State University James Cancer Hospital, Columbus OH
20 University of Alabama Hospital at Birmingham, Birmingham AL

We've all seen the commercials for the Cancer Treatment Centers of America; not one of them—Eastern Regional Medical Center in in Philadelphia, PA; Midwestern Regional Medical Center in Zion, IL; Southwestern Regional Medical Center in Tulsa, OK; and Western Medical Center in
Goodyear, AZ—is even mentioned by US News & World Report.

I wonder why this is.