Electrocoagulation and the risk of cervical neoplasia.

The relationship between electrocoagulation diathermy and the risk of cervical neoplasia was evaluated in a case-control study of 145 women with cervical intraepithelial neoplasia compared with 145 age-matched outpatient control subjects, and 191 cases of invasive cervical cancer compared with 191 control subjects in the hospital for acute conditions unrelated to any of the identified or suspected risk factors for cervical cancer. History of electrocoagulation was associated with an apparently reduced risk of cervical intraepithelial neoplasia (relative risk = 0.50, with 95% confidence interval = 0.29-0.87), and of invasive cancer (relative risk = 0.42, 95% confidence interval = 0.22-0.82). However, this apparent protection could be largely explained in terms of a different frequency of previous Papanicolaou smears in patients and control subjects. When adjustment was made for that variable, the risk estimates of CIN and invasive cancer among women who had undergone electrocoagulation increased to 0.62 and 0.83 and became statistically nonsignificant. Further allowance for other identified potential confounding factors by means of multiple logistic regression raised these estimates to 0.73 and 0.94, respectively. Thus, these data provide evidence against the hypothesis that electrocoagulation may have an important and independent role in the prevention of cervical neoplasia.