Review of negative and low-grade cervical smears in women with invasive cervical cancer after the first 3 years of the national cervical screening programme in Slovenia

Objective: The purpose of the study was to perform a national review of negative, low-grade and inadequate smears reported during the latest screening period before cervical cancer diagnosis in 2006, after the first 3 years of the screening programme. Methods: Among 162 new cervical cancer cases there were 47 (29%) without previous cytology, 47 (29%) with one high-grade smear prior to diagnosis and 68 (42.0%) with at least one previous negative, low-grade, atypical or inadequate smear 1-40 months before diagnosis. Of the latter 68 cases, 37 patients with 59 smears (together with 118 control slides) were included in the review as 31 had smears reported at laboratories no longer operating. Findings were related to the last cytology report before diagnosis as well as to histological type and stage of the cancer. Results: In our study group, 19 (51%) of 37 patients had squamous cell carcinoma, 15 (41%) adenocarcinoma and 3 (8%) adenosquamous carcinoma, compared with 121 (75%), 26 (16%), 12 (7%), respectively, and 3 (2%) other types, for all carcinomas. Twenty-one of 37 women also had high-grade cytology prior to diagnosis of cancer. Women with previous cytology (with or without recent high-grade smears) were more likely to have stage I cancers than those without cytology (P < 0.0001). The expert group upgraded 17 / 33 smears in the patients with squamous carcinomas, which was more than in those with adeno-and adenosquamous carcinomas (5 / 24, P < 0.05). Conclusion: As expected, a higher proportion of smears preceding adenocarcinomas were true negative. Underdiagnosed smears were not related to cancer stage or last cytology report before diagnosis.