Cervical screening and risk of adenosquamous and rare histological types of invasive cervical carcinoma: population based nested case-control study

• Published in: BMJ (Online) Vol. 365; p. l1207
• Main Authors: Lei, Jiayao, Andrae, Bengt, Ploner, Alexander, Lagheden, Camilla, Eklund, Carina, Nordqvist Kleppe, Sara, Wang, Jiangrong, Fang, Fang, Dillner, Joakim, Elfström, K Miriam, Sparén, Pär
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 03.04.2019; BMJ Publishing Group Ltd
• Subjects: Adenocarcinoma; Adenosquamous; Adult; Aged; Carcinoma, Adenosquamous - diagnosis; Carcinoma, Adenosquamous - epidemiology; Carcinoma, Adenosquamous - pathology; Carcinoma, Squamous Cell - diagnosis; Carcinoma, Squamous Cell - epidemiology; Carcinoma, Squamous Cell - pathology; Case-Control Studies; Cervical cancer; Cervical carcinoma; Cervix; Cervix Uteri - pathology; Cytology; Early Detection of Cancer; Female; Health risk assessment; Human papillomavirus; Humans; Incidence; Invasiveness; Medical research; Medical screening; Medicin och hälsovetenskap; Middle Aged; Papillomavirus Infections - diagnosis; Papillomavirus Infections - epidemiology; Papillomavirus Infections - pathology; Population studies; Population-based studies; Registries; Risk; Risk Reduction Behavior; Squamous cell carcinoma; Tumors; Uterine Cervical Neoplasms - diagnosis; Uterine Cervical Neoplasms - epidemiology; Uterine Cervical Neoplasms - pathology; Young Adult; Sweden
• ISSN: 0959-8138; 1756-1833; 1756-1833
• DOI: 10.1136/bmj.l1207

AbstractObjectivesTo examine the association of cervical cytology screening with the risk of adenosquamous cell carcinoma (ASC) and rare histological types of invasive cervical carcinoma (RICC), using comprehensive registry data, and to assess tumour human papillomavirus status of ASC and RICC.DesignNationwide, population based, nested case-control study.SettingSweden.ParticipantsAll cases of invasive cervical carcinoma in Sweden during 2002-11 (4254 confirmed cases after clinical and histopathological review). 338 cases were neither squamous cell carcinoma nor adenocarcinoma, including 164 cases of ASC and 174 cases of RICC (glassy cell carcinoma, clear cell carcinoma, small cell carcinoma, neuroendocrine cell carcinoma, large cell carcinoma, and undifferentiated carcinoma). 30 birth year matched controls from the general Swedish population were matched to each case by applying incidence density sampling.Main outcome measuresConditional logistic regression was used to calculate odds ratios, interpreted as incidence rate ratios, for risk of ASC and RICC in relation to screening status and screening history, adjusted for education. Human papillomavirus distribution of ASC and RICC was based on available archival tumour tissues from most Swedish pathology biobanks.ResultsWomen with two screening tests in the previous two recommended screening intervals had a lower risk of ASC (incidence rate ratio 0.22, 95% confidence interval 0.14 to 0.34) and RICC (0.34, 0.21 to 0.55), compared with women without any test. High risk human papillomavirus was detected in 148/211 (70%) cases with valid human papillomavirus results from tumour tissues. The risk reduction among women with tumours that were positive (incidence rate ratio 0.28, 0.18 to 0.46) and negative (0.27, 0.13 to 0.59) for high risk human papillomavirus was similar, compared with women who did not attend any test.ConclusionsCervical screening is associated with reduced risk of ASC and RICC, and most ASC and RICC are positive for high risk human papillomavirus. This evidence provides a benchmark for evaluating future cervical screening strategies.