Prevalence estimates the number of people alive on a certain date who have ever been diagnosed with cancer. Thus it estimates the burden of cancer diagnoses on the population, and is often used to estimate the demand on the health care system from previously-diagnosed cancer cases, and to judge the overall success of cancer treatment in preventing cancer mortality.
The Texas Cancer Registry provides estimates of the January 1, 2011 10-year limited duration prevalence of cancer in Texas by cancer site. This 10-year limited duration prevalence is defined as persons diagnosed with cancer from January 1, 2001 through December 31, 2010, who were still alive on January 1, 2011.
The tables for 2010 and 2011 prevalence are directly calculated cancer prevalence in Texas. Our previous prevalence data (2005-2009 prevalence estimates) were generated by projecting SEER prevalence onto the Texas population by age, sex, race and ethnicity. By directly calculating cancer prevalence, we know that these numbers are now accurate for Texas residents, and take into account any differences in the Texas prevalence compared with SEER prevalence.
There also exist different ways of dealing with multiple primaries when calculating prevalence, and our tables use “all tumors matching selection criteria”. Therefore, a person with multiple primary cancers will be counted once for the prevalence of each primary cancer they have, but they will only be counted once for “All Sites Combined.” In our earlier (2005-2009) estimated prevalence tables, the SEER prevalence tables we were using to project Texas prevalence used a multiple primary selection of “First Malignant Primary Only”.