Incidence Trends of Cervical Cancer and Its Precancerous Lesions in Women of Central Switzerland from 2000 until 2014

Abstract

Objective: Cervical cancer (CC) screening by Pap smears has led to a decrease in the incidence of CC worldwide. Indeed, the incidence of CC in Switzerland is very low; however, there is a lack of data to evaluate the efficiency of the Pap smear as a screening tool. Until now, only Pap smears have been used and other methods such as the presence of an infection with HPV have not been integrated into the routine screening. The aim of this study is to evaluate trends in the incidence of CC and its precancerous lesions in Central Switzerland, which represents a rural region, with those in urban regions and the entire country of Switzerland.

Methods: All conizations and CC registered between 2000 and 2014 at the Institute of Pathology at the Cantonal Hospital of Lucerne have been included in our study. The incidence of CC and its precancerous lesions have been categorized according to age, stage, morphology, and study period. Age-standardized incidence in the Canton of Zurich and the entire country served as reference for the assessment of trends in CC incidence in the study region.

Results: In Central Switzerland, the number of conizations performed annually has more than doubled over the observed 15 years. There has been a significant increase in precancerous lesions, which were found in approximately 50% of conizations. The total number of CC diagnosed by conization increased by 37.5% and the total of CIN3 increased by 130%. Age-standardized incidence of CC and CIN3 increased from 2.4 to 3.3/100,000 and from 11.6 to 26.9/100,000, respectively. The incidence of CC was lower in Central Switzerland compared to incidence in the Canton of Zurich and in Switzerland generally.

Conclusion: Approximately 50% of all conizations were performed on women without serious precancerous lesions. For this reason, we recommend the adaptation of screening modalities and the use of risk stratification to avoid overtreatment. In light of the forthcoming implementation of an HPV vaccination program, our data provides important baseline information.

Keywords: Switzerland; cervical cancer; cervical intraepithelial neoplasia; conizations; incidence; screening.

Figure 1

Findings in conizations in Central Switzerland, 2000–2014. In total, 272 conizations showed no evidence of dysplasia, 220 showed CIN1, 443 CIN2, 1,000 CIN3, and 70 showed cervical cancer (CC).

Figure 2

Number and proportions of dysplastic findings and cervical cancer (CC) diagnosed by conization in Central Switzerland, 2000–2014. There is a significant increase of conizations (n = 2,005) as well as CIN3 and CIN2 diagnosed by conization (p-value < 0.001, respectively). CC shows a stable course.

Figure 3

Trends in age-standardized incidence of cervical cancer (CC) and CIN3 in conizations in Central Switzerland, 2000–2014. There is a trend toward increasing age-standardized incidence rates (ASIR) of CC (p-value 0.075) and a significant increase of ASIR of CIN3 (p-value < 0.001). There is no significant increase of ASIR of squamous cell carcinoma (SCC) from 1.8/100,000 between 2000 and 2004 to 2.4/100,000 between 2005 and 2009 and between 2010 and 2014 (p-value 0.132) and of adenocarcinoma (AC) from 0.4/100,000 between 2000 and 2004 to 0.6/100,000 between 2005 and 2009 to 0.9/100,000 between 2010 and 2014 (p-value 0.423).

Figure 4

Trends in number of histological subtypes of cervical cancer (CC) by FIGO stage at time of diagnosis, Central Switzerland 2000–2014. There is a trend of increasing numbers of findings with FIGO IA (p-value 0.077) and a significant increase of findings FIGO >II (p-value < 0.001). If CC was diagnosed in FIGO IA, adenocarcinoma (AC) was found in 9.8% and squamous cell carcinoma (SCC) in 90.0%, compared to FIGO IB with 29% of AC and 71% of SCC.

Figure 5

Trends in age-standardized incidence rates (ASIR) of cervical cancer (CC) in Switzerland, the Canton of Zurich and Central Switzerland. There are similar trends in ASIR of CC in Switzerland and in the Canton of Zurich over the course of the observed time. CC incidence in Central Switzerland was lower in earlier years, but all rates converged in 2012/2013 (Central Switzerland: 4.8/100,000, Switzerland: 5.1/100,000, and Canton of Zurich: 5.3/100,000).