Cancer Case Characteristics
Table 1 presents frequencies and distributions of 14,738 AANHPI California females with invasive breast cancer diagnosed from 2008 through 2012. Of them, 71% were diagnosed at ages of 50 or older, 65% with localized disease, and 34% with advanced disease (Table 1). Approximately 74% of AANHPI breast cancer cases resided in more culturally distinct neighborhoods (AANHPI enclave Q4 and Q5) while 26% resided in the least culturally distinct neighborhoods (AANHPI enclave Q1-Q3). The majority of AANHPI breast cancer cases (57%) resided in high nSES neighborhoods (Q4 and Q5) while 43% resided in low SES neighborhoods (Q1-Q3).
For AANHPI females, AAIR decreased with higher ethnic enclave quintiles such that females residing in the least culturally distinct neighborhoods had the highest incidence rate of breast cancer (Q1 AAIR: 115.10 per 100,000; 95% CI: 105.57, 125.32) while those living in highest AANHPI ethnic enclave neighborhoods (more culturally distinct) had the lowest incidence rate (Q5 IR: 95.21; 95% CI: 93.07, 97.39) (Table 2). Relative to AANHPI females residing in the highest ethnic enclave neighborhoods, females residing in the lowest ethnic enclave had a 21% higher incidence rate of invasive breast cancer (95% CI: 1.11, 1.32). Residing in neighborhoods that were less culturally distinct was associated with increasing incidence of breast cancer (Ptrend = 0.01).
Furthermore, the AAIR increased with nSES such that AANHPI females residing in the lowest SES neighborhoods (Q1 AAIR: 83.59; 95% CI: 78.67, 88.73) had the lowest incidence rate while those residing in the highest SES neighborhoods had the highest incidence rate of breast cancer (Q5 AAIR: 109.20 per 100,000; 95% CI: 105.97, 112.52) (Table 3). Relative to those residing in the lowest SES neighborhoods, AANHPI females residing in the highest SES neighborhoods had a 30% higher incidence rate of invasive breast cancer (IRR = 1.30; 95% CI: 1.22, 1.40). Residing in neighborhoods of higher SES was associated with an increasing incidence of breast cancer (Ptrend = 0.01).
Table 4 shows AAIR and IRR of breast cancer for each category of the joint variable compared to in the reference group, high enclave+low nSES. AANHPI females living in neighborhoods of low ethnic enclave+high nSES (IRR = 1.32 95% 1.25 – 1.39), low ethnic enclave+low nSES (IRR = 1.23; 95% 1.16 – 1.29), and high ethnic enclave+high nSES (IRR = 1.20; 95% 1.15 – 1.24) had a statistically significantly higher incidence rate of breast cancer compared to females living in high ethnic enlave+low nSES neighborhoods.
In a subgroup analysis by stage of disease, AANHPI females with localized stage at diagnosis residing the least culturally distinct neighborhoods (least culturally distinct) had the highest incidence rate of breast cancer (Q1 AAIR: 75.16 per 100,000; 95% CI: 67.55, 83.46) while those living in highest AANHPI ethnic enclave neighborhoods (more culturally distinct) had the lowest incidence rate (Q5 IR: 61.78; 95% CI: 60.05, 63.54) (Table S1). In contrast, AANHPI females with advanced stage at diagnosis residing in the second to lowest AANHPI ethnic enclave neighborhood had the highest incidence rate of breast cancer (Q2 AAIR: 38.24 per 100,000; 95% CI: 34.67, 42.09) (Table S1). Moreover, AANHPI females living in highest vs. lowest SES neighborhoods had higher incidence rates of localized (Q5 vs. Q1 IRR = 1.44, 95% CI 1.32 - 1.57) and advanced stage (Q5 vs. Q1 IRR = 1.12, 95% CI 1.00 - 1.25) breast cancer (Table S2). Similar associations were observed for joint variable of ethnic enclave and nSES when comparing AANHPI females that resided in low ethnic enclave+high nSES neighborhoods to AANHPI females that reside in high ethnic enlave+low nSES neighborhoods for localized stage (IRR = 1.40; 95% 1.31 – 1.50) and advanced stage at diagnosis (IRR = 1.18; 95% 1.07 – 1.29) (Table S3).
Table 1. Study Characteristics of Female Asian American/ Native Hawaiian/Pacific Islander Invasive Breast Cancer Cases Reported in California from 2008 through 2012 (N=14,738)
|
|
n
|
%
|
|
|
|
Age at Diagnosis (years)
|
|
|
20-29
|
101
|
0.68%
|
30-39
|
947
|
6.4%
|
40-49
|
3,240
|
22%
|
50-59
|
4,095
|
28%
|
60-69
|
3,493
|
24%
|
70-79
|
1,944
|
13%
|
80+
|
918
|
6.2%
|
Year of Diagnosis
|
|
|
2008
|
2,702
|
18%
|
2009
|
2,766
|
19%
|
2010
|
2,945
|
20%
|
2011
|
3,097
|
21%
|
2012
|
3,228
|
22%
|
SEER Summary Stage*
|
|
|
Localized
|
9,586
|
65%
|
Regional/Distant
|
4,960
|
34%
|
Ethnic Enclave
|
|
|
Q1 Low Enclave
|
557
|
4.0%
|
Q2 Low Enclave
|
1,273
|
8.0%
|
Q3 Low Enclave
|
2,106
|
14%
|
Q4 High Enclave
|
3,184
|
22%
|
Q5 High Enclave
|
7,618
|
52%
|
Neighborhood SES
|
|
|
Q1 Low Neighborhood SES
|
1,134
|
8.0%
|
Q2 Low Neighborhood SES
|
2,052
|
14%
|
Q3 Low Neighborhood SES
|
3,167
|
21%
|
Q4 High Neighborhood SES
|
3,872
|
26%
|
Q5 High Neighborhood SES
|
4,513
|
31%
|
*Unknown stage (n) = 192 (1.31%)
Table 2. Invasive Breast Cancer Age-Adjusted Incidence Rates (AAIR) and Incidence Rate Ratios (IRR) by Ethnic Enclaves for Asian American/Native Hawaiian/ Pacific Islander Females Reported in California from 2008 through 2012
|
Ethnic Enclave
|
Population
|
Cases (n)
|
AAIR1 (95% CI)
|
IRR (95% CI)
|
|
|
|
|
|
|
|
Q5 High
(more ethnic)
|
7,136,940
|
7,618
|
95.21 (93.07 - 97.39)
|
(ref)
|
|
Q4
|
2,752,040
|
3,184
|
104.50 (100.86 - 108.24)*
|
1.09 (1.05 - 1.14)
|
|
Q3
|
1,647,505
|
2,106
|
112.54 (107.72 - 117.52)*
|
1.18 (1.13 - 1.24)
|
|
Q2
|
969,415
|
1,273
|
113.36 (107.13 - 119.87)*
|
1.19 (1.12 - 1.26)
|
|
Q1 Low
(less ethnic)
|
383,450
|
557
|
115.10 (105.57 - 125.32)*
|
1.21 (1.11 - 1.32)
|
|
p-trend
|
|
|
|
0.01**
|
1Age adjusted incidence rates (AAIR) per 100,000 using the 2000 U.S. standard population (18 age groups- Census P25-1130); 95% Confidence Intervals (CI)
* Indicates statistical significance (P<0.05) comparing to high ethnic enclave
** indicates statistical significance (p<0.05) of a trend
Table 3. Invasive Breast Cancer Age-Adjusted Incidence Rates (AAIR) 1 and Incidence Rate Ratios (IRR) by neighborhood SES (nSES) for Asian American/Native Hawaiian/ Pacific Islander Females Reported in California from 2008 through 2012
nSES
|
Population
|
Cases (n)
|
AAIR1 (95% CI)
|
IRR (95% CI)
|
|
|
|
|
|
|
|
Q1 Low
|
1,209,465
|
1,134
|
83.59 (78.67 - 88.73)
|
(ref)
|
|
Q2
|
1,948,800
|
2,052
|
90.18 (86.26 - 94.24)*
|
1.08 (1.00 - 1.16)
|
|
Q3
|
2,752,600
|
3,167
|
100.54 (97.02 - 104.15)*
|
1.20 (1.12 - 1.29)
|
|
Q4
|
3,220,080
|
3,872
|
107.88 (104.47 - 111.38)*
|
1.39 (1.21 - 1.38)
|
|
Q5 High
|
3,758,570
|
4,513
|
109.20 (105.97 - 112.52)*
|
1.30 (1.22 - 1.40)
|
|
p-trend
|
|
|
|
0.00800**
|
1Age adjusted incidence rates (AAIR) per 100,000 using the 2000 U.S. standard population (18 age groups- Census P25-1130); 95% Confidence Intervals (CI)
* Indicates statistical significance (P<0.05) comparing to low nSES
** indicates statistical significance (p<0.05) of a trend
Table 4. Invasive Breast Cancer Incidence Rate Ratios1 by Ethnic Enclave and Neighborhood SES for Asian American/Native Hawaiian/ Pacific Islander females reported in California from 2008 through 2012
|
N
|
n
|
AAIR (95%CI)
|
IRR (95%CI)
|
|
|
|
|
|
High Ethnic Enclave & Low nSES
|
4,437,330
|
4,532
|
88.63 (86.03 - 91.30)
|
(ref)
|
High Ethnic Enclave & High nSES
|
5,451,650
|
6,270
|
106.09 (103.44 - 108.79)*
|
1.20 (1.15 - 1.24)
|
Low Ethnic Enclave & Low nSES
|
1,473,460
|
1,821
|
108.95 (103.93 - 114.16)*
|
1.23 (1.16 - 1.29)
|
Low Ethnic Enclave & High nSES
|
1,526,910
|
2,115
|
116.70 (111.69 - 121.89)*
|
1.32 (1.25 - 1.39)
|
1Age adjusted incidence rates (AAIR) per 100,000 using the 2000 U.S. standard population (18 age groups- Census P25-1130); 95% Confidence Intervals (CI)
2Low Enclave (Q1 through 3) and High Enclave (Q4 & 5)
3Low nSES (Q1 through 3) and High nSES (Q4 & 5)
* Indicates statistical significance (P<0.05) comparing to high ethnic enclave & low nSES