Lower accuracy of cytological screening for high-grade squamous intraepithelial neoplasia in women over 50 years of age in Japan

Background: As the population ages in developed countries, the number of Pap smears for cervical cancer screening of older women is increasing. There is concern that cervical atrophy may cause misinterpretation of results for this segment of the population. The present study evaluated the accuracy of screening for high-grade intraepithelial lesions (HSILs) in women younger or older than 50 years, to determine whether aging affects cytological interpretation. Methods: Patients with HSIL cytology (N = 1565) were dichotomized into those aged 20–49 years or aged ≥ 50 years. Association between histology results and age was examined. Pearson’s chi-squared test and Cochran-Armitage trend test were used for statistical analysis. Results: The positive predictive value (PPV) for cervical intraepithelial neoplasia (CIN)2 and worse was 65.2% (62/95) in older women but 87.3% (482/552) in younger women (p < 0.001). Older patients had a significantly lower PPV (p = 1.69 × 10^–8). Separately analyzing chronic cervicitis, CIN1 and overt cancer grouped together, compared with another group composed of CIN2 and CIN3, we found that the PPV for CIN2 and CIN3 was lower in older than in younger women [44.2% (42/95)-vs-82.4% (455/552), p < 0.001], respectively. Conclusions: HSILs are associated with a wide range of disease categories as age increases, and the accuracy of HSIL interpretation is lower in older women.