Objective To estimate the regression, persistence, and progression of untreated cervical intraepithelial neoplasia grade 2 (CIN2) lesions managed conservatively as well as compliance with follow-up protocols.
Design Systematic review and meta-analysis.
Data sources Medline, Embase, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) from 1 January 1973 to 20 August 2016.
Eligibility criteria Studies reporting on outcomes of histologically confirmed CIN2 in non-pregnant women, managed conservatively for three or more months.
Data synthesis Two reviewers extracted data and assessed risk of bias. Random effects model was used to calculate pooled proportions for each outcome, and heterogeneity was assessed using I² statistics.
Main outcome measures Rates of regression, persistence, or progression of CIN2 and default rates at different follow-up time points (3, 6, 12, 24, 36, and 60 months).
Results 36 studies that included 3160 women were identified (seven randomised trials, 16 prospective cohorts, and 13 retrospective cohorts; 50% of the studies were at low risk of bias). At 24 months, the pooled rates were 50% (11 studies, 819/1470 women, 95% confidence interval 43% to 57%; I²=77%) for regression, 32% (eight studies, 334/1257 women, 23% to 42%; I²=82%) for persistence, and 18% (nine studies, 282/1445 women, 11% to 27%; I²=90%) for progression. In a subgroup analysis including 1069 women aged less than 30 years, the rates were 60% (four studies, 638/1069 women, 57% to 63%; I²=0%), 23% (two studies, 226/938 women, 20% to 26%; I²=97%), and 11% (three studies, 163/1033 women, 5% to 19%; I²=67%), respectively. The rate of non-compliance (at six to 24 months of follow-up) in prospective studies was around 10%.
Conclusions Most CIN2 lesions, particularly in young women (<30 years), regress spontaneously. Active surveillance, rather than immediate intervention, is therefore justified, especially among young women who are likely to adhere to monitoring.
Systematic review registration PROSPERO 2014: CRD42014014406.

中文翻译：

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主动监护下未经治疗的2级宫颈上皮内瘤变的临床病程：系统评价和荟萃分析

目的评估保守治疗并遵守随访方案的未经治疗的宫颈上皮内瘤样变2级（CIN2）病变的消退，持续性和进展。
设计系统的审查和荟萃分析。
数据来源1973年1月1日至2016年8月20日的Medline，Embase和护理及相关健康文献累积指数（CINAHL）。
入选标准研究报告经组织学证实为非孕妇的CIN2结局，保守治疗了3个或更多个月。
数据综合两名审稿人提取了数据并评估了偏见风险。使用随机效应模型计算每个结果的合并比例，并使用I ²统计量评估异质性。
主要结果指标在不同的随访时间点（3、6、12、24、36和60个月），CIN2的回归，持续或进展率以及违约率。
结果确定了包括3160名女性在内的36项研究（7项随机试验，16项前瞻性队列研究和13项回顾性队列研究；其中50％的研究存在低偏见风险）。在24个月时，回归的合并率为50％（11个研究，819/1470名女性，95％置信区间43％至57％； I ² = 77％），回归的合并率为32％（8个研究，334/1257名女性，23个％至42％；我²（82％）表示持续性，18％（九项研究，282/1445名女性，11％至27％； I ² = 90％）表示进展。在包括1069名年龄在30岁以下的女性中的亚组分析中，发病率分别为60％（四项研究，638/1069女性，57％至63％； I ² = 0％），23％（两项研究，226/938女性） ，分别为20％至26％； I ² = 97％）和11％（三项研究，163/1033名女性，为5％至19％； I ² = 67％）。前瞻性研究的不依从率（随访6至24个月）约为10％。
结论大多数CIN2病变，尤其是年轻女性（<30岁）会自发消退。因此，进行主动监视而不是立即干预是合理的，尤其是在可能坚持监视的年轻女性中。
系统审核注册PROSPERO 2014：CRD42014014406。