Brain Cancer Mortalityin the United States

Joint work with:

Zixing Fang, UCLA

David Gregorio, Univ Connecticut

U.S. Brain Cancer Mortality1986-1995

deaths rate* (95% CI)Children (age <20): 5,062 0.75 (0.66-0.83)Adults (age 20+): 106,710 6.0 (5.8-6.2)Adult Women: 48,650 4.9 (4.7-5.0)Adult Men: 58,060 7.2 (7.0-7.5)

* annual deaths / 100,000

Brain CancerKnown risk factors:• High dose ionizing radiation• Selected congenital and genetic disorders

Explains only a small percent of cases.

Potential risk factors:N-nitroso compounds?, phenols?, pesticides?, polycyclic aromatic hydrocarbons?, organic solvents?

Adjustments

• Age

• Gender

• Ethnicity (African-American, White, Other)

All subsequent analyses where adjusted for:

0 200 400 600

M iles

S M R2.07-42.82 (highest 10%)1.20-2.060.83-1.190.50-0.82Zero cases (1867 counties)

Brain Cancer Mortality, Children 1986-1995

Cuzick-Edward’s Test: Children

k p-value200 0.04 500 0.13

Tango’s Excess Events Test:Children

p-value 1000 0.005 2000 0.06 5000 0.2110000 0.29

15

37

4

2

6

0 200 400 600

M iles

Risk Fa ctor Color Ke yHigh Risk, Not Significant

Spatial Scan Statistic, Children

Children: Seven Most Likely Clusters

Cluster Obs Exp RR p= 1. Carolinas 86 51 1.7 0.242. California 16 4.9 3.3 0.743. Michigan 318 250 1.3 0.744. S Carolina 24 10 2.5 0.795. Kentucky-Tenn 127 88 1.4 0.796. Wisconsin 10 2.4 4.1 0.987. Nebraska 12 3.6 3.3 0.99

Conclusions: Children

Some evidence of global spatial clustering, but rather weak.

No statistically significant clusters detected.

Any part of the pattern seen on the original map may be due to chance.

How About Adults?

0 200 400 600

M iles

S M R9.46-24.44 (highest 10%)8.05-9.457.27-8.046.72-7.266.17-6.715.68-6.165.19-5.674.51-5.183.40-4.50Zero Cases (312 counties)

Brain Cancer Mortality, Adults 1986-1995

Cuzick-Edward’s k-NN: All Adults

k p-value 4000 0.0001 10000 0.0001

Tango’s EET: All Adults

p-value 1000 0.0001 2000 0.0001 5000 0.0001 10000 0.0001

1

7

1 0

1 1

3

4

2

6

5 1 2

9

1 3

8

Spatial Scan Statistic: Adults

0 200 400 600

M iles

S M R9.46-24.44 (highest 10%)8.05-9.457.27-8.046.72-7.266.17-6.715.68-6.165.19-5.674.51-5.183.40-4.50Zero Cases (312 counties)

Brain Cancer Mortality, Adults 1986-1995

Cuzick-Edward’s: Women

k p-value1500 0.0001 3000 0.0001

Tango’s EET: Women

p-value 1000 0.0001 2000 0.0001 5000 0.0001 10000 0.0001

13

1 2

11

10

8

6

2

7 5

9

13

4

0 200 400 600

M iles

Risk Fa ctor Color Ke yLow Risk, p < 0.05High Risk, p < 0.05Low Risk, Not SignificantHigh Risk, Not Significant

Spatial Scan Statistic, Women

Women: Most Likely Clusters Cluster Obs Exp RR p= 1. Arkansas et al. 2830 2328 1.22 0.00012. Carolinas 1783 1518 1.17 0.00013. Oklahoma et al. 1709 1496 1.14 0.0034. Minnesota et al. 2616 2369 1.10 0.01

10. N.J. / N.Y. 1809 2300 0.79 0.000111. S Texas 127 214 0.59 0.000112. New Mexico et al. 849 1049 0.81 0.0001

Cuzick-Edward’s: Men

k p-value2000 0.0001 4000 0.0001

Tango’s EET: Men

p-value 1000 0.0001 2000 0.0001 5000 0.0001 10000 0.0001

4

2

8

9

11

1 2

1 4

6

13 3

1 0

5

7

151

0 200 400 600

M iles

Risk Fa ctor Color Ke yLow Risk, p < 0.05High Risk, Not SignificantHigh Risk, p < 0.05

Spatial Scan Statistic: Men

Men: Most Likely Clusters Cluster Obs Exp RR p= 1. Kentucky et al. 3295 2860 1.15 0.00012. Carolinas 1925 1658 1.16 0.00013. Arkansas et al. 1143 964 1.19 0.0014. Washington et al. 1664 1455 1.14 0.0035. Michigan 1251 1074 1.17 0.005

11. N.J. / N.Y. 2084 2615 0.80 0.000112. S Texas 157 262 0.60 0.000113. New Mexico et al.1418 1680 0.84 0.000114. Upstate N.Y. et al.1642 1895 0.87 0.0001

Conclusions: Adults

Strong evidence of global spatial clustering.

It is possible to pinpoint specific areas with higher and lower rates that are statistically significant, and unlikely to be due to chance.

The exact borders of detected clusters are uncertain.

Similar patterns for men and women.

Conclusion: General

Tests for spatial randomness are very useful additions to cancer maps, in order to determine if the observed patterns are likely due to chance or not.

Different tests provide complementary information.