Organization of screening in technically advanced countries: Iceland.

Mass screening for cervical carcinoma in Iceland over the past 20 years (1964-1983) has resulted in a 60% drop in the incidence of and mortality from the disease in the country. A study of the screening histories of the 77 incident cases of grossly invasive cervical cancer diagnosed in Iceland in the past nine years showed that 70% of the tumours occurred in women who had failed to attend screening or had done so very irregularly. Approximately 20% of the cervical cancers were either diagnostic or therapeutic failures, in that the women had been diagnosed with cytological changes but this did not result in the prevention of the tumour. The remaining 10% of the incident cervical carcinomas seemed to have escaped cytological detection and proved to be unusual types of cancer. Prevention of the last cases of cervical cancer is becoming increasingly laborious because of difficulties in maintaining interest among the public to attend regular screening. Women may escape surveillance of a cytological abnormality unless they are constantly reminded about follow-up visits. A small, but significant number of the tumours may continue to escape detection because of their unusual nature, but alterations in sampling techniques and increased awareness of the rarer forms of the disease could alter this.