Comparison of risk factors for invasive squamous cell carcinoma and adenocarcinoma of the cervix: Collaborative reanalysis of individual data on 8,097 women with squamous cell carcinoma and 1,374 women with adenocarcinoma from 12 epidemiological studies

Authors

  • The International Collaboration of Epidemiological Studies of Cervical Cancer

    Corresponding author
    1. Cancer Research UK Epidemiology Unit, University of Oxford, Nuffield Department of Clinical Medicine, Richard Doll Building, Roosevelt Drive, Oxford OX3 7LF, UK. Fax: +44-1865-289610. Email: aberring@jhsph.edu or jane.green@ceu.ox.ac.uk
    • Cancer Research UK Epidemiology Unit, University of Oxford, Nuffield Department of Clinical Medicine, Richard Doll Building, Roosevelt Drive, Oxford OX3 7LF, UK. Fax: +44-1865-289610. Email: aberring@jhsph.edu or jane.green@ceu.ox.ac.uk

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    • Steering committee: C. La Vecchia (Chairman), F.X. Bosch, R. Herrero, A. Hildesheim, D. Skegg, D. Thomas

      Writing and analysis committee: P. Appleby, V. Beral, A. Berrington de González, D. Colin, S. Franceschi, J. Green, J. Peto, M. Plummer, S. Sweetland

      Collaborators: T. Rajkumar, Cancer Institute (WIA), Chennai, India; J. Cuzick, Cancer Research UK Epidemiology Group, Wolfson Institute of Preventive Medicine, UK; P. Appleby, V. Beral, A. Berrington de González, D. Bull, K. Canfell, J. Green, S. Sweetland, Cancer Research UK Epidemiology Unit, Oxford UK; S. Kjaer, Danish Cancer Society, Denmark; R. Painter, M. Vessey, Department of Public Health, Oxford UK; J. Daling, M. Madeleine, R. Ray, D. Thomas, Fred Hutchinson Cancer Research Center, Seattle, USA; R. Herrero, Guanacaste Epidemiological Project, Costa Rica; N. Ylitalo, Department of Medical Epidemiology and biostatistics, Karolinska Institut, Sweden; F.X. Bosch, S. de Sanjosé, X. Castellsague, V. Moreno, Institut Català d'Oncologia, Spain; D. Hammouda, Institut Nacional de Santé Publique, Algiers, Algeria; J. Peto, Institute of Cancer Research, Sutton, UK; E. Negri, Istituto di Ricerche Farmacologiche ‘Mario Negri’, Milan, Italy; M. Alvarez, O. Galdos, C. Santos, C. Velarde, Instituto Nacional de Enfermedades Neopláscias ‘Dr Eduardo Caceres Grazini’, Lima, Peru; D. Colin, S. Franceschi, N. Muñoz, M. Plummer, International Agency for Research on Cancer, Lyon, France; J. Dillner, I. Silins, Lund University, Mälmo, Sweden; S. Bayo, Ministere de la Sante Publique et d'Affaires Sociales, Bamako, Mali; N. Chaouki, Ministry of Health, Morocco; P Rolon, Ministry of Health, Paraguay; L. Brinton, A. Hildesheim, J. Lacey Jr, M. Schiffman, National Cancer Institute, NIH, USA; L. Stein, M.I. Urban, Cancer Epidemiology Research Group, National Health Laboratory Service, Johannesburg, South Africa; P. Hannaford, Royal College of General Practitioners Oral Contraception Study, UK; S. Chichareon, Prince of Songkla University, Songkla, Thailand; F. Sitas, The Cancer Council New South Wales, Sydney Australia; J. Eluf-Neto, Universidade de São Paulo, Brazil; C. La Vecchia, University of Milan, Italy; D. Skegg, University of Otago, New Zealand; M. Pike, G. Ursin, University of Southern California, USA; C. Ngelangel, University of the Philippines, Manila, The Philippines; I.T. Gram, University of Tromsø, Norway; T. Farley, O. Meirik, World Health Organisation, Geneva, Switzerland.


Abstract

Squamous cell carcinomas account for about 80% of cancers of the uterine cervix, and the majority of the remainder are adenocarcinomas. There is limited evidence on the extent to which these histological types share a common etiology. The International Collaboration of Epidemiological Studies of Cervical Cancer has brought together and combined individual data on 8,097 women with invasive squamous cell carcinoma, 1,374 women with invasive adenocarcinoma and 26,445 women without cervical cancer (controls) from 12 epidemiological studies. Compared to controls, the relative risk of each histological type of invasive cervical cancer was increased with increasing number of sexual partners, younger age at first intercourse, increasing parity, younger age at first full-term pregnancy and increasing duration of oral contraceptive use. Current smoking was associated with a significantly increased risk of squamous cell carcinoma (RR = 1.50, 95% CI: 1.35–1.66) but not of adenocarcinoma (RR = 0.86 (0.70–1.05)), and the difference between the two histological types was statistically significant (case-case comparison p < 0.001). A history of screening (assessed as having had at least one previous nondiagnostic cervical smear) was associated with a reduced risk of both histological types, but the reduction was significantly greater for squamous cell carcinoma than for adenocarcinoma (RR = 0.46 (0.42–0.50) and 0.68 (0.56–0.82), respectively; case–case comparison, p = 0.002). A positive test for cervical high-risk HPV-DNA was a strong risk factor for each histological type, with 74% of squamous cell carcinomas and 78% of adenocarcinomas testing positive for HPV types 16 or 18. Squamous cell and adenocarcinoma of the cervix share most risk factors, with the exception of smoking. © 2006 Wiley-Liss, Inc.

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