Cervical cancer among Asian subgroups in California, 19902004

1
Cervical cancer among Asian subgroups in
California, 1990-2004

• Janet Bates, MD MPH
• California Cancer Registry
• NAACCR Annual Meeting
• Denver, Colorado
• June 10, 2008

2
Background

• National cancer statistics show lower overall
  cancer rates among Asians in the US
• Asians have wide variability in countries of
  origin, immigration history, culture, language,
  education and SES that influence cancer risk
• Aggregated cancer statistics for Asians mask
  important differences among subgroups
• Limited national cancer data available on Asian
  subgroups

3
Asians in California

• California has largest Asian population of any
  state
• 3.7 million Asians 12 of state population
• 90 of California Asian population comprised of 6
  subgroups Chinese, Filipino, Japanese, Korean,
  South Asian, and Vietnamese

4
Study purpose

• To describe patterns of cervical cancer
  incidence, mortality, and survival among 6 major
  Asian subgroups in California

5
Methods

• Cervical cancer cases diagnosed among California
  residents 1990-2004
• Included all 6 Asian subgroups and non-Hispanic
  whites (NHW)
• Variables
• Age (lt40, 40-64, 65 years)
• SES quintile (composite census-based measure)
• Stage (local, regional, distant, unknown)
• Surgery (none, local, hysterectomy, other)
• Radiation (none, any)
• Chemotherapy (none, any)

Yost K et al, Cancer Causes Control, 2001
6
Methods

• Cervical cancer incidence rates and trends
  calculated using SEERstat
• Cervical cancer survival probabilities (5 and 10
  year) calculated using Kaplan-Meier method
• Multivariate evaluation of survival calculated
  using Cox proportional hazards modeling, adjusted
  for stage, age, SES, and treatment factors

7
Results
8
Demographic characteristics age and SES
P for comparison with NHW is significant at lt
0.05
9
Clinical characteristics stage distribution
P for comparison with NHW is significant at lt
0.05
10
Clinical characteristics stage distribution
Lowest proportion of cases diagnosed at local
stage were found among South Asian, Filipino, and
Korean women stage distribution among South
Asian women not significantly different from NHW
P for comparison with NHW is significant at lt
0.05
11
Cervical cancer incidence trends 1990-2004
12
Cervical cancer incidence trends 1990-2004
Vietnamese had highest incidence throughout
period, as well as most dramatic decline
13
Cervical cancer incidence trends 1990-2004
followed by Korean, then Filipino women
14
Cervical cancer incidence trends 1990-2004
Chinese women and NHW had comparable rates in
1990-1992
15
Cervical cancer incidence trends 1990-2004
but by 2002-2004 incidence rates were lower
among Chinese women
NHW
Chinese
16
Cervical cancer incidence trends 1990-2004
Rates among Japanese and South Asian women also
declined, but trend not statistically significant
Japanese
South Asian
17
Unadjusted cause-specific 5- and 10-year
cervical cancer survival
18
Unadjusted cause-specific cervical cancer survival
19
Clinical characteristics stage distribution
Lowest proportion of cases diagnosed at local
stage were found among South Asian, Filipino, and
Korean women stage distribution among South
Asian women not significantly different from NHW
P for comparison with NHW is significant at lt
0.05
20
Risk of death due to cervical cancer among Asian
subgroups
Referent group is Non-Hispanic Whites
21
Risk of death due to cervical cancer among Asian
subgroups
Referent group is non-Hispanic whites
22
Risk of death due to cervical cancer among Asian
subgroups
Referent group is non-Hispanic whites
23
Risk of death due to cervical cancer among Asian
subgroups
Referent group is non-Hispanic whites
24
Discussion

• Higher incidence among Vietnamese, Korean,
  Filipino women mirror international patterns
• South Asian rates relatively low despite high
  rates in countries of origin

25
Discussion

• Variability in cervical cancer incidence is
  largely attributed to screening
• Expect populations with low screening to have
  higher incidence
• Examined cervical cancer screening survey data
  from the California Health Interview Survey (CHIS)

26
Percent pap test in past 3 years by Asian
subgroup, California
Source California Health Interview Survey 2003
27
Percent pap test in past 3 years and cervical
cancer incidence by Asian subgroup, California
Source California Health Interview Survey 2003
28
Limitations

• Limited number of cases in some subgroups
• Misclassification of race is possible
• Risk factor data (HPV subtypes, smoking, diet,
  co-morbidities, immigration data, etc.) not
  available

29
Summary

• Distinct variations among subgroups in patterns
  of cervical cancer incidence and survival
• Practice of aggregating statistics for Asians
  masks these differences
• Public health programs targeting cervical cancer
  screening and prevention must take these
  differences into account

30
Summary

• Lower risk of cervical cancer death among
  Vietnamese, Korean, Filipino, and South Asian
  women
• Few studies on this
• Further evaluation of reasons for this apparent
  survival advantage is needed

31
Acknowledgements

• Co-authors Brenda Hofer, Arti Parikh-Patel
• CDC Cancer supplement coordinators Meg Watson,
  Mona Saraiya
• CCR research and surveillance program staff
  Mark Allen, Allyn Fernandez Ami, Sandy Kwong