Does screening history explain the ethnic differences in stage at diagnosis of cervical cancer in New Zealand?
BACKGROUND
There are ethnic disparities in cervical cancer survival in New Zealand. The objectives of this study were to assess the associations of screening history, ethnicity, socio-economic status (SES) and rural residence with stage at diagnosis in women diagnosed with cervical cancer in New Zealand during 1994-2005.


METHODS
The 2323 cases were categorized as 'ever screened' if they had had at least one smear prior to 6 months before diagnosis, and as 'regular screening' if they had had no more than 36 months between any two smears in the period 6-114 months before diagnosis. Logistic regression was used to estimate the associations of screening history, ethnicity, SES and urban/rural residence with stage at diagnosis.


RESULTS
The percentages 'ever screened' were 43.3% overall, 24.8% in Pacific, 30.5% in Asian, 40.6% in Māori and 46.1% in 'Other' women. The corresponding estimates for 'regular screening' were 14.0, 5.7, 7.8, 12.5 and 15.3%. Women with 'regular screening' had a lower risk of late stage diagnosis [odds ratio (OR) 0.16, 95% confidence interval (CI) 0.10-0.26], and the effect was greater for squamous cell carcinoma (OR 0.12, 95% CI 0.07-0.23) than for adenocarcinoma (OR 0.32, 95% CI 0.13-0.82). The increased risk of late-stage diagnosis (OR 2.72, 95% CI 1.99-3.72) in Māori (compared with 'Other') women decreased only slightly when adjusted for screening history (OR 2.45, 95% CI 1.77-3.39).


CONCLUSIONS
Over half of cases had not been 'ever screened'. Regular screening substantially lowered the risk of being diagnosed at a late stage. However, screening history does not appear to explain the ethnic differences in stage at diagnosis.
Brewer
Naomi
N
Centre for Public Health Research, Massey University, Wellington, New Zealand. n.brewer@massey.ac.nz
Pearce
Neil
N
Jeffreys
Mona
M
Borman
Barry
B
Ellison-Loschmann
Lis
L
D005260:Female; D006801:Humans; D009367:Neoplasm Staging; D009520:New Zealand / Q000453:epidemiology; D012424:Rural Population / Q000706:statistics & numerical data; D012959:Socioeconomic Factors; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000208:ethnology* / Q000401:mortality; D014626:Vaginal Smears / Q000706:statistics & numerical data