gms | German Medical Science

50. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds)
12. Jahrestagung der Deutschen Arbeitsgemeinschaft für Epidemiologie (dae)

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie
Deutsche Arbeitsgemeinschaft für Epidemiologie

12. bis 15.09.2005, Freiburg im Breisgau

Trend in breast cancer Survival – a comparison of White and African American women

Meeting Abstract

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  • Malabika Sarker - Hygiene Institute, Heidelberg
  • Ismail Jatoi - Department of Surgery, Uniformed Services University,Department of Defense, Maryland, USA
  • Heiko Becher - Hygiene Institute, Heidelberg

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie. Deutsche Arbeitsgemeinschaft für Epidemiologie. 50. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds), 12. Jahrestagung der Deutschen Arbeitsgemeinschaft für Epidemiologie. Freiburg im Breisgau, 12.-15.09.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05gmds379

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/gmds2005/05gmds212.shtml

Veröffentlicht: 8. September 2005

© 2005 Sarker et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction

Differences in survival between White and African-American breast cancer cases have been observed in previous studies. Results revealed that African American (AA) women with breast cancer have markedly poorer survival probability than white women [1]. There are several explanation for that; poor socio economic status, lack of access to medical care, less utilization of screening, variations in treatment, co morbid conditions, lack of compliance with treatment recommendations, and late stage presentation [2], [3]). Growing literature also suggest [4] that AA women have tumor of more aggressive histopathology regardless of age for each stage of disease that white women.

While differences in access to healthcare were suspected as one major factor, this could only play a minor role in women entitled to the US department of Defense (DoD) healthcare system. Health services of DoD provides free and equal access to all of it’s beneficiaries. Therefore, disparities in outcome after diagnosis of breast cancer should not be entirely ascribed to inequalities in access to health care. However in a previous publication, data collected from DoD, Jatoi et al. [5] reported a widening disparity in survival between AA and white women. In addition, they found a temporal trend in estimating hazard ratio. The overall hazard ratio 1.27 for AA vs. whites for the period 1980-1984 has been increased to 1.46 for the period 1995-1999.

To explore this further, we present estimates for absolute 5-year survival of both AA and White women by age, calendar period and stage of the disease using the same data set.

Study Population and Methods

This is a retrospective study of White and African American women diagnosed with breast cancer and treated in the US department of defense health care system. The medical records of all Breast cancer clients from 1980-1999 were retrieved from the United States Department of Defense (DoD) Automated Central Tumor Registry (ACTUR). In DoD health care system all eligible beneficiaries have equal access to services either free of charge or at a nominal fee. All women diagnosed with primary breast cancer have been selected from the original database. Variables selected for statistical analysis were age, race, year of diagnosis, stage of tumor and vital status. Absolute survival for 5 years was investigated because the data base did not include cause of death. Survival probability of the patient was estimated based on a proportional hazard regression model. For statistical analysis PROC PHREG was applied by using the statistical package SAS (SAS Institute, Inc., Cary. NC).

Results

Total 23,612 women were included in the analysis. Details of data collection and the definition of the data set for analysis is presented elsewhere [5]. Overall white women had a better survival compared to African American women irrespective of age, year of diagnosis and stage of tumor. There is a slight overall improvement in survival in whites, however, given tumor stage the survival remains almost unchanged with a slight but insignificant decrease. In African American women there is a small decrease in survival overall which appears large given stage of the tumor at diagnosis (see table 1 [Tab. 1] and table 2 [Tab. 2] for a sample of the results). Older women and younger women have poorer survival although there is a widen disparity in survival even at the similar stage and age between AA and white women. The oldest (80 yrs+) and the youngest women (30-39 years) with stage 4 breast cancer have the poorest 5 year survival. 30-39 years old white and AA women with stage 2 diagnosed in between 1980-84 have 5 year survival of 77.7% and 72.9% respectively, whereas the survival probability for women with same age and stage diagnosed after 1994 are 76.6 and 65.4. The decrease of survival in white women with time is much less than AA women (Table 1 [Tab. 1]).

Discussion

This study has examined the temporal trend in survival difference between White and African American women diagnosed with breast cancer in between 1980 - 1998. Result shows that, in any point of time survival is poorer in younger and older women, a result that was presented before using hazard ratios and given here more explicit using survival rates. Unlike other studies, we found that the survival probability has been gradually decreased with time after controlling for age and stage of the disease. While there is an improvement in survival overall, there can be several explanations for this findings. First, the result from SEER data [6] revealed that changes in 5 year survival over time bear little relationship to change in cancer mortality because the change is apparently related to changing pattern of diagnosis. Our data show that the proportion of cases analyzed at early stage indeed increased with calendar year, in particular in whites. Secondly, it may also be attributable to the overall survival after a diagnosis of breast cancer, rather than disease specific survival. Finally, there is significant variation in breast cancer mortality and survival rates reported in different settings.

However, it is very difficult to explain the reasons for the widening disparity in survival between AA women and white women with time. Irrespective of treatment status, AA women have poor survival than white women. Most possible explanation could be delay in initiation of therapy or failure to administer adjuvant therapy in AA women. Finally growing obesity and life style could also be risk factors for the poor survival of AA women. In conclusion, specific research should be targeted to identify the factors responsible for the widening racial disparity of survival in time.


References

1.
Chevarley F, White E. Recent trends in breast cancer mortality among white and black US women. Am J Public Health. 1997 87:775-81
2.
Lyman GH, Kuderer NM, Lyman SL, Cox CE, Reintgen D, Baekey P.Importance of race on breast cancer survival. Ann Surg Oncol. 1997 4:80-7
3.
Joslyn SA Racial differences in treatment and survival from early-stage breast carcinoma. Cancer. 2002 ;95:1759-66
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Henson DE, Chu KC, Levine PH. Histologic grade, stage, and survival in breast carcinoma: comparison of African American and Caucasian women. Cancer. 2003 ;98:908-17
5.
Jatoi I, Becher H, Leake CR. Widening disparity in survival between white and African-American patients with breast carcinoma treated in the U. S. Department of Defense Healthcare system. Cancer. 2003 ;98:894-9
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Welch HG, Schwartz LM, Woloshin S. Are increasing 5-year survival rates evidence of success against cancer? JAMA. 2000 ;283:2975-8