Treatment of cervical intraepithelial neoplasia (CIN) detectable at screening has helped reduce the incidence of cervical cancer, but has also led to overtreatment. The estimates of overtreatment have often focused on a particular grade of CIN or age group. The aim of this paper was to provide a nationwide population-based estimate of the frequency of CIN treatment per prevented cervical cancer case in a well-screened population. We retrieved the data from the Danish National Population, Patient, Health Insurance, Pathology, and Cancer Registers, and calculated annual age-standardized CIN treatment rates. We estimated the frequency of CIN treatment per prevented cervical cancer case by comparing the cumulative life-time risk of CIN treatment from 1996 onward, with the difference in the cumulative life-time risks of cervical cancer in the prescreening and the screening periods. Since 1996, more than 5,000 CIN treatments were undertaken annually in the population of about 2.2 million women aged 15-84 years, and at present 5.2 CIN treatments are undertaken per 1,000 women aged 20-49. About six women have undergone CIN treatment for each prevented cervical cancer. The frequency of CIN treatment increased after 2004 and at present almost eight women are treated per prevented cervical cancer case. Screening, though effective in reducing the incidence of cervical cancer, leads also to a considerable burden of CIN treatment. Future trends in CIN treatment should be closely monitored.Cervical intraepithelial neoplasia (CIN) can be detected at screening, so that its progression to cervical cancer can be stopped. 1 The burden of cervical cancer has decreased, because the introduction of screening in Europe and Northern America in the 1960's, with data from several long-standing cancer registers showing that the incidence rates in most of these countries have more than halved since then. 2 However, not all untreated CIN would progress to cancer, 3 and there is at present no reliable method to distinguish between progressing and nonprogressing CIN. As a consequence, the reduction in the burden of cervical cancer for some women has been achieved by treating nonprogressive CIN in other women, and CIN treatment may potentially lead to adverse obstetric outcomes. 4,5 Even for highgrade CIN such as CIN3, the proportion without progression to cancer appears to be substantial. For example, following an unethical experiment in New Zealand in 1965-1974, during which women diagnosed with carcinoma in situ were withheld adequate treatment, 31% of those with ''minimum disturbance'' of the lesion developed cervical cancer in the following 30 years. 6 In the currently well-screened women, CIN lesions are probably diagnosed at an earlier stage compared with the New Zealand experiment. Lesions detected earlier may be smaller and have a lower potential for

Unlike for human papillomavirus screening, little is known about the possible age-dependent variation in the outcomes of cervical cytology screening. The aim of our study was to describe age-related outcomes of five cytological technologies in a population-based screening program targeting women aged 23-59 years. All cervical cytology from women residing in Copenhagen has been analyzed in the laboratory of the Department of Pathology, Hvidovre University Hospital. We studied five technology phases: (1) conventional cytology with manual reading, (2) conventional cytology with 50% automatically signed out as normal, (3) liquid-based cytology (LBC) with 50% automatically signed out as normal, (4) LBC with 25% automatically signed out as normal, and (5) LBC with 25% automatically signed out as normal and with 16 preselected areas for attention in manual reading. We calculated proportion of samples with atypical squamous cells of undetermined significance or worse (≥ASCUS) by age and technology phase. We included 391 140 samples. The proportion of ≥ASCUS increased steadily from 3.8% in phase 1 to 6.0% in phase 5. This pattern varied considerably across age groups. In women aged 23-34 years, the proportion almost doubled, relative proportion 1.96 (95% confidence interval: 1.84-2.08). An opposite development was seen in women aged 45-59 years, relative proportion 0.68 (95% confidence interval: 0.57-0.82). Technological upgrading of cytology strongly affected the outcome of cervical screening for young women. If corroborated with data from other laboratories, these findings call for caution in implementation of new cytology screening technologies.

Adherence to follow-up after conization was poor in Denmark. Our findings suggest that because of this poor adherence, recommendations for long-term annual follow-up after treatment of cervical intraepithelial neoplasia may not be highly effective. Shorter follow-up schedules using highly sensitive tests appear attractive.

The study objective was to determine the parental origin of triploidy in relation to findings from early risk assessment in a combined screening program between 2004 and the end of 2006. Triploidy was diagnosed in six chorion villus samples and two samples from missed abortions. After informed consent, quantitative fluorescence polymerase chain reaction analysis was performed on the five cases where we received blood from both parents and tissue from fetuses. In four cases the origin of the triploidy was paternal and in one maternal, in accordance with previous findings in type I and type II triploidies. Finding triploidy is possible by risk assessment (ultrasound and double test), and thereby women may have the opportunity for early termination of pregnancy.