In some countries, such as the United Kingdom, women have long term intensive surveillance after conservative treatment for high grade cervical intraepithelial neoplasia, whereas in others, such as the Netherlands and Finland, they return to regular screening after a few years. The second choice is based on the consistent observation that most recurrences of cervical intraepithelial neoplasia occur in the first two to three years after treatment.1

In this week's BMJ, Strander and colleagues provide strong evidence that women treated for cervical intraepithelial neoplasia grade 3 have a long lasting excess risk of invasive cervical cancer.2 Among more than 130 000 women with this condition, the age adjusted incidence was more than double that of the general population up to 20-25 years after diagnosis. The excess incidence was greater in women treated at older age and in recent years.

How do these findings translate into clinical recommendations? The important question is how different follow-up schedules compare in terms of effectiveness and cost in preventing the excess …