Determinants of inequalities in cervical cancer stage at diagnosis and survival in New Zealand

Abstract

The aim of this study is to assess whether ethnic inequalities in cervical cancer mortality are due to differences in survival independent of stage and age at diagnosis, and to assess the contribution of screening to stage at diagnosis. Demographic data and cervical screening history were collected for 402 women with histologically proven primary invasive cervical cancer, diagnosed in New Zealand between 1 January 2000 and 30 September 2002. Date of death was available for women who died up to 30 September 2004. A Cox proportional hazard model showed that, after adjusting for age, the Māori mortality rate was 1.80 times (95% CI 1.07-3.04) that of non-Māori. This reduced to 1.25 (95% CI 0.74-2.11) when stage at diagnosis was also adjusted for. Among determinants of late stage at diagnosis, older age and being Māori significantly increased the risk, while screening was protective. These results indicate that later stage at diagnosis is the main determinant of Māori women's higher mortality from cervical cancer. Improving cervical screening among Māori women would reduce stage at diagnosis and therefore ethnic inequalities in mortality.