Socio-demographic and reproductive determinants of cervical neoplasia in seven sub-Sahara African countries.

BACKGROUND: Since most human papilloma virus (HPV) infections regress without any intervention, HPV is a necessary but may not be a solely sufficient cause of cervical intraepithelial neoplasia (CIN) and cervical cancer. Hence, the influence of cofactors on progression from cervical HPV infection to high-grade CIN and invasive cervical cancer has been a subject of intensive research. OBJECTIVE: We assessed the effect of socio-demographic and sexual reproductive factors on the prevalence of invasive cervical cancer and CIN diagnosed in cross-sectional cervical cancer screening projects carried out in seven sites of different sub-Saharan countries. METHODS: Between January 2000 and August 2007, healthy women aged 25-59 who participated in the screening projects were interviewed for socio-demographic, reproductive, and behavioral characteristics, investigated for disease confirmation with colposcopy, and had biopsies directed from colposcopically abnormal areas by trained local physicians. Odds ratios (ORs) and their 95% confidence intervals (CIs) from logistic regression analyses were used to assess the effect of women characteristics on CIN 1, CIN 2-3, CIN 3, and invasive cancer outcome measures. RESULTS: Among 47,361 women screened and investigated for disease confirmation, CIN 1 was diagnosed in 1,069 (2.3%), CIN 2 in 517 (1.1%), CIN 3 in 175 (0.5%), and invasive cancer in 485 (1.0%). The site-specific prevalence of CIN 2-3 lesions ranged from 0.3 to 5.1% and from 0.2 to 1.9% for invasive cancers. Risk factors for CIN 2-3 were being widowed or separated versus currently married (OR 1.3, 95% CI 1.0-1.7 a); and having had at least four pregnancies versus zero or one pregnancy (OR at least 1.4-fold, 95% CI 1.1-1.8). Risk factors for invasive cancer were being widowed or separated versus currently married (OR 2.0, 95% CI 1.3-3.1); and having had at least three pregnancies versus zero or one pregnancy (OR at least 3.0-fold, 95% CI 2.1-4.2). Additionally, cervical cancer risk increased with increasing age, age at menarche, and age at marriage, while the risk decreased with increasing level of education and in those with some form of employment compared to housewives. CONCLUSION: The exposure of the exocervix and/or the increased levels of estrogen and progesterone for more prolonged periods during pregnancy in multiparous women and the vulnerability of widowed/separated women in society might result in increased risk of cervical neoplasia more so among women exposed to HPV infection. High parity probably explains the persistently high rates of cervical cancer in sub-Saharan Africa.

Accuracy of visual screening for cervical neoplasia: Results from an IARC multicentre study in India and Africa.

Visual inspection-based screening tests, such as visual inspection with 4% acetic acid (VIA) and with Lugol's iodine (VILI), have been proposed as alternatives to cytology in mass screening programs. To date, there is only limited information on the accuracy of these tests in detecting High-grade Squamous Intraepithelial Lesions (HSIL). Eleven cross-sectional studies involving 56,939 women aged 25-65 years were conducted in Burkina Faso, Congo, Guinea, India, Mali and Niger to evaluate the accuracy of VIA and VILI performed by health workers. A common protocol and questionnaire was used. For final diagnosis, all women were investigated with colposcopy and biopsies were taken when necessary. Data from the studies were pooled to calculate sensitivity, specificity and predictive values of the tests for the detection of HSIL. Of the screened women, 16.1% and 16.4% were positive on examination using, respectively, VIA and VILI; 1,063 were diagnosed with HSIL. The pooled sensitivity, specificity, positive and negative predictive values for VIA were 76.8% (95% CI: 74.2-79.4%), 85.5% (95% CI: 85.2-85.8%), 9.4% (95% CI:8.8-10.8%) and 99.5% (95% CI:99.4-99.6%), respectively. The values were 91.7% (95% CI: 89.7-93.4%), 85.4% (95% CI: 85.1-85.7%), 10.9% (95% CI: 10.2-11.6%) and 99.8% (95% CI:99.7-99.9%), respectively for VILI. The range of sensitivity and specificity for VIA was 56.1-93.9% and 74.2-93.8%, respectively, between studies and were 76.0-97.0 % and 73.0-91.3% for VILI. VILI had a significantly higher sensitivity than VIA in detecting HSIL, but specificity was similar. VILI appears to be a more accurate visual test for use in screening and treatment programs in low-resource settings.