Effect of visual screening on cervical cancer incidence and mortality in Tamil Nadu, India: a cluster-randomised trial

Background Cervical cancer is the most common cancer among women in developing countries. We assessed the effect of screening using visual inspection with 4% acetic acid (VIA) on cervical cancer incidence and mortality in a cluster randomised controlled trial in India. Methods Of the 114 study clusters in Dindigul district, India, 57 were randomised to one round of VIA by trained nurses, and 57 to a control group. Healthy women aged 30 to 59 years were eligible for the study. Screen-positive women had colposcopy, directed biopsies, and, where appropriate, cryotherapy by nurses during the screening visit. Those with larger precancerous lesions or invasive cancers were referred for appropriate investigations and treatment. Cervical cancer incidence and mortality in the study groups were analysed and compared using Cox regression taking the cluster design into account, and analysis was by intention to treat. The primary outcome measures were cervical cancer incidence and mortality. Results Of the 49311 eligible women in the intervention group, 31343 (63.6%) were screened during 2000-03; 30958 control women received the standard care. Of the 3088 (9.9%) screened positive, 3052 had colposcopy, and 2539 directed biopsy. Of the 1874 women with precancerous lesions in the intervention group, 72% received treatment. In the intervention group, 274 430 person years, 167 cervical cancer cases, and 83 cervical cancer deaths were accrued compared with 178 781 person-years, 158 cases, and 92 deaths and in the control group during 2000-06 (incidence hazard ratio 0.75 [95% CI 0.55-0.95] and mortality hazard ratio 0.65 [0.47-0.89]). Interpretation VIA screening, in the presence of good training and sustained quality assurance, is an effective method to prevent cervical cancer in developing countries.