The AJCC clinical and pathologic stage groups included in the PUF are a TNM-based system coded or reported according to the edition corresponding to the patient’s diagnosis year. The fifth edition of the AJCC Staging Manual is used to represent patients’ cases diagnosed from 1998 through 2002. The sixth edition describes the anatomic extent of disease for patients diagnosed from 2003 through 2009. Patients diagnosed in 2010 are staged according to the seventh edition of the AJCC Staging Manual Data. Exercise caution when using staging information. Staging definitions may change between editions of the AJCC staging manuals, and rules delineating "stageable histologies" have become more specific over time, beginning with the 5th edition of the staging manual. Investigators may observe variability with the completeness of reported staging information over time. There have also been changes in CoC program standards and NCDB data reporting requirements in recent years. Rules defining which personnel within a facility were authorized to assign stage and the extent to which registry staff were directed to copy the recorded stage information have been both tightened and relaxed over the years captured in the PUF. In addition, the universal implementation of the Collaborative Stage Data Collection System (CS) in 2004 across all cancer registries in the United States contributed to a reduction in the coding of physician-reported staging in subsequent years.