Biomedical subjects

Holly Samociuk

Publications and source records attributed to Holly Samociuk.

7 recordsLinked to original sources

PubMed2006

Race-specific geography of prostate cancer incidence.

BACKGROUND: This study evaluated geographic distribution of race-specific prostate cancer incidence in Connecticut and Massachusetts. This cross-sectional analysis of census and cancer registry data included records of 29,040 Whites and 1,647 African Americans diagnosed with incident prostate cancer between 1994 and 1998. A spatial scan statistic was used to detect and test significance of the geographic variation in race-specific incidence rates within the two-state area. RESULTS: Significant geographic variation in age-adjusted incidence rates among both White and African American men was observed, with little overlap noted between distributions. Identified locations reflected patterns of residential segregation and socio-economic conditions. Among Whites, places with higher than expected incidence had higher socioeconomic status than places with lower than expected incidence. No discernable relationship between social indicators and rate variation among African Americans was evident. CONCLUSION: Differences in race-specific geographic distribution of prostate cancer incidence do not suggest a shared environmental etiology. Further study of genetic, behavioral and health care factors affecting the occurrence and/or reporting of the disease is warranted. This study highlights the need for race- and geographic-specific interventions to better control disease within at-risk communities and for on-going analysis into social and contextual factors that contribute to observed disparities between African Americans and Whites in the occurrence of cancer.

Black or African American↗

PubMed2006

Effects of study area size on geographic characterizations of health events: prostate cancer incidence in Southern New England, USA, 1994-1998.

BACKGROUND: We consider how representations of geographic variation in prostate cancer incidence across Southern New England, USA may be affected by selection of study area and/or properties of the statistical analysis. METHOD: A spatial scan statistic was used to monitor geographic variation among 35,167 incident prostate cancer cases diagnosed in Massachusetts, Connecticut and Rhode Island from 1994 to 1998, in relation to the 1990 populations of men 20+ years of age living in that region. Results from the combined-states analysis were compared to those from single-states. Impact of scanning procedures set to examine up to 50% or no more than 10% of at-risk populations also was evaluated. RESULTS: With scanning set to 50%, 5 locations in the combined-states analysis were identified with markedly distinct incidence rates. Fewer than expected cases were estimated for nearly all Connecticut, Rhode Island and West Central Massachusetts, whereas census tracts on and around Cape Cod, and areas of Southwestern Connecticut and adjacent to greater Boston were estimated to have yielded more than expected incidence. Results of single-state analyses exhibited several discrepancies from the combined-states analysis. More conservative scanning found many more locations with varying incidence, but discrepancies between the combined- and single-state analysis were fewer. CONCLUSION: It is important to acknowledge the conditional nature of spatial analyses and carefully consider whether a true cluster of events is identified or artifact stemming from selection of study area size and/or scanning properties.

Adult↗

PubMed2006

Cancer map patterns: are they random or not?

BACKGROUND: Maps depicting the geographic variation in cancer incidence, mortality or treatment can be useful tools for developing cancer control and prevention programs, as well as for generating etiologic hypotheses. An important question with every cancer map is whether the geographic pattern seen is due to random fluctuations, as by pure chance there are always some areas with more cases than expected, or whether the map reflects true underlying geographic variation in screening, treatment practices, or etiologic risk factors. METHODS: Nine different tests for spatial randomness are evaluated in very practical settings by applying them to cancer maps for different types of data at different scales of spatial resolution: breast, prostate, and thyroid cancer incidence; breast cancer treatment and prostate cancer stage in Connecticut; and nasopharynx and prostate cancer mortality in the U.S. RESULTS: Tango's MEET, Oden's Ipop, and the spatial scan statistic performed well across all the data sets. Besag-Newell's R, Cuzick-Edwards k-NN, and Turnbull's CEPP often perform well, but the results are highly dependent on the parameter chosen. Moran's I performs poorly for most data sets, whereas Swartz Entropy Test and Whittemore's Test perform well for some data sets but not for other. CONCLUSIONS: When publishing cancer maps we recommend evaluating the spatial patterns observed using Tango's MEET, a global clustering test, and the spatial scan statistic, a cluster detection test.

Adolescent↗

PubMed2005

Lumping or splitting: seeking the preferred areal unit for health geography studies.

BACKGROUND: Findings are compared on geographic variation of incident and late-stage cancers across Connecticut using different areal units for analysis. RESULTS: Few differences in results were found for analyses across areal units. Global clustering of incident prostate and breast cancer cases was apparent regardless of the level of geography used. The test for local clustering found approximately the same locales, populations at risk and estimated effects. However, some discrepancies were uncovered. CONCLUSION: In the absence of conditions calling for surveillance of small area cancer clusters ('hot spots'), the rationale for accepting the burdens of preparing data at levels of geography finer than the census tract may not be compelling.

Journal Article↗

PubMed2004

Geographic distribution of prostate cancer incidence in the era of PSA testing, Connecticut, 1984 to 1998.

OBJECTIVES: To evaluate the geographic variation of prostate cancer incidence in Connecticut during a 15-year period: before the introduction of prostate-specific antigen (PSA) testing (1984 to 1988), during its introduction (1989 to 1993), and after its widespread adoption (1994 to 1998). METHODS: A spatial scan statistic was used to detect and test the significance of the geographic rate variation among 29,944 incident cases. RESULTS: During 1984 to 1988, eight locations had incidence rates that differed significantly from the statewide level; for 1989 to 1993, only two locations were identified. By 1994 to 1998, a significant rate variation was noted for 10 locations around Connecticut. CONCLUSIONS: The observed geographic variation of incidence rates may reflect differing opportunities to uncover latent cases at given locales.

Adenocarcinoma↗

PubMed2003

Breast cancer surveillance using gridded population units, Connecticut, 1992 to 1995.

PURPOSE: To assess geographic variation in invasive breast cancer across Connecticut using gridded population areas to enumerate cases and the population at-risk. METHODS: The state's land mass was divided into 5168, 1-by-1 square mile areas and the population of women, 20+ years of age, within each location was estimated by areal interpolation of the 1990 US Census Block Group STF-3A data file. Using information on breast cancer incidence, 1992 to 1995, from the Connecticut Tumor Registry, latitude-longitude coordinates for place of residence at the time of breast cancer diagnosis were determined for 8530 records and assigned to appropriate grid locations. A spatial scan statistic was used to detect variation in incidence and test the significance of observed differences across the state. Standardized Incidence Ratios (SIRs) described the proportional change in the age-adjusted breast cancer incidence rate across gridded locations. RESULTS: The statewide age-adjusted invasive cancer incidence rate was 163.6/100,000 women/year. The spatial scan statistic identified three locations around Connecticut with significantly low incidence rates and four places where rates were significantly high. The most probable place of low incidence was rural Northeastern Connecticut where risk of disease, relative to elsewhere around the state, was 0.73 (p = 0.001). The most probable location of elevated incidence was a suburban location in Southwestern Connecticut with a relative risk of 2.02 (p = 0.001). CONCLUSIONS: Visual representation of disease incidence and underlying populations at-risk according to gridded units provides a useful tool for assessing small area variation in disease patterns.

Adult↗

PubMed2002

Geographic differences in invasive and in situ breast cancer incidence according to precise geographic coordinates, Connecticut, 1991-95.

To evaluate geographical variation of invasive and in situ breast cancer incidence rates using precise geographical coordinates for place of residence at diagnosis, latitude-longitude coordinates pertaining to 10,601 invasive and 1,814 in situ breast cancers for Connecticut women, 1991-95, were linked to US Census information on the 2,905 State census block groups. A spatial scan statistic was used to detect geographic excess or deficits in incidence and test the statistical significance of results, without prior assumptions about the size or location of such areas. The age adjusted invasive cancer incidence rate was 165.3/100,000 women/year. The spatial scan statistic identified 3 places with significantly low incidence rates and 4 places where rates were significantly high. The most probable location of low incidence was rural northeastern Connecticut where risk of disease, relative to elsewhere around the state, was 0.70 (p = 0.0001); the most probable place of elevated incidence was north central Connecticut where a relative risk of 1.34 (p = 0.002) was observed. Incidence of in situ disease was estimated to be significantly high for north central Connecticut (RR = 1.84; p = 0.0001). Geographic differences of invasive and in situ breast cancer incidence were observed. Examining cancer events at the lowest available level of data aggregation is beneficial in highlighting localized rate variations. Such information may enable public health officials to target additional resources for promoting breast cancer screening to specific locations.

Adult↗