Active surveillance may be a suitable option in selected, particularly younger, women with CIN2, a systematic review and meta-analysis has concluded.

Medline, Embase and CINAHL databases were searched for studies reporting on outcomes of CIN2 managed conservatively for at least three months, published between 1973 and 2016.

Of 250 potential studies 36 met the eligibility criteria. They included data on 3,160 women with histologically confirmed CIN2. Seven studies were randomised controlled trials, 16 were prospective and 13 retrospective cohort studies. The study sizes ranged from 12 to 924 subjects, and follow-up data were collected for 3 to 72 months (median 16 months).

The most typical follow-up consisted of 3-4 monthly colposcopic and cytological examination, with cervical biopsies performed either routinely or when progression was suspected. There was considerable heterogeneity between studies.

Regression, persistence and progression rates are shown in table 1, below. In younger women (under 30) the regression rate was 38% at 6 months and increased with the duration of observation to 60% at 24 months. Regression was less common and progression of disease more common in older women. In older women rates of disease progression were higher the longer the period of observation.

Overall, 15 cases of adenocarcinoma in situ were identified during follow-up. There were also 15 cases of invasive cervical cancer (15/3,160, 0.5%) all but two of which were stage 1A1.

A sub-analysis looked at default from follow-up rates in selected retrospective studies. The rates were 19% (95% CI: 7-35%) at 6 months, 15% (95% CI: 6-25%) at 12 months and 8% (95% CI: 1-21%) at 24 months.

Until further data is forthcoming, let us hope gynaecologists factor in future obstetric potential when managing women with CIN2, and consider diligent active surveillance, where appropriate, in carefully selected women.

The study authors state:

‘Our results show that active surveillance is justified in selected women with untreated, histologically confirmed CIN2 lesions, particularly if they are young and the likelihood of compliance with follow-up is high.’

However, the author of an accompanying editorial1 cautions: ‘Knowledge of the rates of regression from CIN2 are reassuring but they must be presented in a meaningful way alongside clear information about the effects of both surveillance and treatment, so women can make fully informed choices.’

She adds: ‘Knowing that the chance of regression is 50-60% still means taking a gamble that surveillance is simply delaying treatment. Even a small risk of cancer (0.5% in this study) may still be unacceptable to some.’

Dr Chris Barclay

Tainio K, Athanasiou A, Tikkinen KAO et al. Clinical course of untreated cervical intraepithelial neoplasia grade 2 under active surveillance: systematic review and meta-analysis. BMJ 2018;360:k499