Cancer Incidence by Primary Site

The following section examines incidence rates for the nineteen most common groups of cancers. For each site, the age-adjusted incidence rate is presented graphically for white males, black males, white females and black females for the whole SRRHIS region and for the Georgia and South Carolina SRRHIS counties separately (1991-1993); for the Atlanta SEER area and for all SEER areas (1990-1992). Bar graphs for each cancer type show the incidence rates for each race/gender group for the different geographic areas. This presentation should illustrate how SRRHIS area rates compare to those of other areas for similar demographic groups and may suggest some important cancer control opportunities.

The National Cancer Institute's SEER program and the Atlanta SEER area are frequently referred to in this report for comparison rates. The SEER program has been collecting cancer surveillance data from at least nine population based registries in different geographic areas of the United States since 1973, with high standards for quality control and rates of reporting completeness. Incidence data for 1992 are thought to be 98 to 99 percent complete (Kosary, 95). SEER data included in this report represent almost ten perecent of the United States population. Data come from five states: Connecticut, Hawaii, Iowa, New Mexico, and Utah and four metropolitan areas: Detroit, Michigan; Atlanta, Georgia; San Francisco-Oakland, California; and Seattle-Puget Sound, Washington.

The SRRHIS population should be considered somewhat unique among cancer surveillance registries. While SEER looks to the State Health Registry of Iowa for representation of rural rates, cancer rates for an essentially rural Southern population have not been clearly reported and evaluated in recent decades. The Atlanta SEER program has collected data on ten rural Georgia counties since 1978, but this population totals only about 100,000, so it takes many years of data to estimate stable rates and, therefore, changes over time cannot be taken into account.

Occasionally it may be noted that rates for a particular sex/race group are unusually high or low in the Georgia or South Carolina SRRHIS counties. Closer examination of these anomalies may show the unusual rate to be localized to the rural areas, or the more metropolitan areas around Augusta and Savannah. Whether the unusual rate relates to underreporting, residents at higher risk, statistical variation, or some other factor probably cannot be determined at this time. However, investigators will be aware that these questions need to be carefully considered for quality control, cancer control or risk assessment measures. An example of this would be the high rate of invasive cervical cancer among black women in both the Georgia and South Carolina populations, which on closer examination can be seen to be focused among the rural population compared to the Augusta and Savannah residents. This is probably due to less frequent Pap smear screening among the more rural black women. One of the major advantages of a population based surveillance program such as the SRRHIS registry is the opportunity to identify and investigate unusual patterns of disease.