Figure 2From: Geographical clustering of prostate cancer grade and stage at diagnosis, before and after adjustment for risk factorsObserved vs. expected block group rates of high grade tumors, and significant clusters. Proportion of prostate cancer cases with histologic grade of 3 or 4, compared to proportion expected based on overall Maryland rate, Maryland Cancer Registry, 1992–1997, N = 18949. A spatial scan statistic was used to identify non-overlapping clusters of statistically significant high or low rates (table 3).Back to article page