Many women with cervical intraepithelial neoplasia grade 2 (CIN2) could opt for surveillance rather than immediate local excision as about half will regress spontaneously.

The findings from a systematic review and meta-analysis by Finnish researchers are especially relevant for young women in whom regression rates were about 60% and for whom active treatment could increase the risk of pregnancy loss and preterm births.

The review identified 36 studies with outcomes from more than 3,000 women with histologically proved CIN2 lesions.

Regression was noted in 46% of women at 12 months and 50% at 24 months. Even at the extremes of surveillance, regression was seen in 42% of women at three months and 44% of women at 60 months.

Progression to CIN3 or worse increased with time – 5% at three months, 14% at 12 months, 18% at 24 months and 24% at 36 months.

Regression rates were higher and progression rates were lower in a sub-group of women under 30 years of age.

“Our results show that active surveillance is justified in selected women with untreated, histologically confirmed cervical intraepithelial neoplasia grade 2 (CIN2) lesions, particularly if they are young and the likelihood of compliance with follow-up is high,” the study authors said.

“In 1,000 women aged less than 30 with a diagnosis of CIN2, 600 will experience regression, 230 will remain unchanged, and 110 will progress within two years of active surveillance.”

They said the woman’s age, values and preferences, pregnancy plans, likelihood of compliance, as well as clinical findings such as the presence of a visible transformation zone should all be considered.

“The benefits of spontaneous regression and minimal impact on future reproduction should be balanced against the risk of non-adherence to follow-up, the risk of invasion, and the costs of repeated visits on an individual basis.”

An accompanying editorial in the BMJ said other considerations were the effects of local treatment including pain, bleeding, menstrual disturbance and time off work.

“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.”

The editorial also said there was a need for biomarkers to help distinguish ‘truly progressive CIN from regressive disease’.