Background and objective: The National Cervical Screening Program in Australia recommends 2 yearly screening in women 18-20 to 69 years. Since the introduction of organised screening in Australia in 1991, the incidence and mortality rates of cervical cancer among women over 20 years of age have fallen remarkably. However it is not known that this decline has been uniform in all ethnic groups and whether all women have shared, or are sharing, equally in the benefits of an organised approach to cervical screening. The aim of this PhD project was to examine cervical screening and its relationship to country of birth and socioeconomic status in New South Wales.
Method and materials: I examined cervical cancer screening in NSW by country of birth and socioeconomic status (SES) using three approaches. First I compared trends in incidence and mortality of cervical cancer by birthplace before and after introduction of organised screening program in 1991. Second I examined screening behaviour in women born in Middle Eastern and Asian countries, for whom cultural factors may be important in determining participation in cervical screening. Two linkage studies were done to obtain information on birthplace and cervical screening behaviour because the Pap Test Register (PTR) in NSW does not collect information on country of birth. For the first, I linked data from cohorts of women from the New South Wales (NSW) Midwives Data (MDC) to the PTR and, for the second, I linked data from cohorts of women from the Admitted Patients’ Data Collection (APDC) to the PTR. Third I undertook an analysis of the use of liquid based cytology (LBC) in cervical screening in NSW women in relation to a number of factors that may influence the use of this new technology, including SES and % of Non English Speaking Background as an indicator of country of birth.
Results: Organised cervical screening, introduced from 1991, may have been effective in reducing the incidence and mortality of the cervical cancer in the whole population of women 20+ years of age in NSW, although there was only weak evidence for a fall in mortality in women 50+ years of age. Women born in Asia, the Middle East and North Africa appeared to have shared in these reductions to a similar degree to Australian-born women. Women of reproductive age (<40 years) born in Asian and Middle-eastern countries were less likely than Australian-born women to participate in cervical screening at the recommended interval. Their likelihood of screening also varied less with socioeconomic status, parity and smoking than it did in Australian-born women. Women >40 years of age born in Asia, but not those born in the Middle East, had lower screening rates than Australian born women of this age, and their screening rates were again largely uninfluenced by SES. In both age groups, the screening rates were least in women born in South Central Asia. The disparities were less in women selected for study following an episode of hospital care. Australia’s cervical screening program is based on the use of conventional cytology and women must pay for adjunctive LBC. LBC uptake in NSW is high (~30% of all women screened) but steady. LBC uptake varies with age in a similar way to screening participation. LBC uptake is most strongly determined by whether or not it was taken up in the preceding cervical screen and also depends on the preceding smear result, age, socioeconomic status, area of residence, proportion of non-English speaking background people in the area and the type of health practitioner who takes the smear.
Conclusions: Incidence of and mortality from cervical cancer fell after the introduction of organised cervical screening in NSW. While this fall was shared by migrant women from Asia and the Middle East, their participation in cervical screening at the recommended interval is less than that in Australian women. The disparity in women from South Central Asia is particularly great. Language and cultural factors are probably the main causes of these differences; SES appears not to be important. Women’s contact with the health service for reasons other than cervical screening may reduce these barriers. Use of adjunctive LBC, while strongly determined by a range of other factors, including in particular the most recent cytology result and SES, appeared also to be less in women of non-English speaking background than in other women in NSW. The persisting disparities in cervical screening uptake by country of birth in NSW, particularly in women from South Central Asia, present a challenge to cervical screening services and for research.