Spontaneous Regression of Cervical Intraepithelial Neoplasia 2: A Meta-analysis.

Background: Cervical intraepithelial neoplasia (CIN) is a precancerous condition that, if progresses, can cause cervical cancer. Less severe forms such as CIN1 regress spontaneously for most of the cases, but for high-grade CIN (CIN2 or CIN3), have higher potentials for progression.

Objective: Aim of the present study was to obtain reliable estimates of spontaneous regression and progression rates of CIN2.

Methods: Data were extracted from eligible studies identified after literature search in electronic databases, and meta-analyses were performed by pooling the regression and progression rates reported by these studies. Meta-regression analyses were performed for the identification of factors affecting regression rate.

Results: Sixteen studies (1,481 patients; 14.86 months [95% CI 9.25-20.48] follow-up; 28.23 years [95% CI 25.07-31.39] age) were included in the meta-analysis. Overall regression rate in these conservatively observed patients was 42.66% (95% CI 35.41-49.91), but regression rate was higher in studies that recruited patients with CIN2 (50.85% [95% CI 36.11-65.60]) in comparison with those that recruited patients without discrimination of CIN2 with CIN3 (36.31% [95% CI 27.67-44.95]. Progression rate in CIN2 patients was 10.28% [95% CI 3.72-16.84]). Age was significantly negatively associated with regression rate (coefficient -1.72 [-3.53 to 0.10]; p = 0.061).

Conclusion: Spontaneous regression rate of CIN2 is considerably high, especially in younger years.