Cervical cancer and cytology screening in New Zealand.

Cytology screening, used in New Zealand since 1955 at an intensity comparable to that in Canada generally, has not favourably affected incidence and mortality rates for cervical cancer; these have actually risen significantly in 20 to 34-year-old New Zealand women. Canadian claims that mortality falls are related to intensity of cytological screening are not justifiable, so that the significance of the 'pre-cancers' revealed by cytology and the value of population screening would seem to be doubtful.