This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Surgeons use different procedures to remove abnormal cells in the cervix (the neck of the womb) and treat early cervical cancer. These treatments effectively reduce the risk that cancer will develop and spread, but they carry a risk of premature birth in future pregnancies. New research ranked the success and risks of different surgical treatments.
The review brought together studies including almost 89,000 women who had cell changes in the cervix (either pre- or early cancer).
Overall, the review found a trade-off between cancer prevention and the risk of problems in future pregnancies. Procedures that removed more cervical tissue reduced the risk of recurrence but increased the risk of a future premature birth.
The researchers recommend that a woman’s age, wishes for future childbearing, and the type and extent of abnormal cells, should drive the choice of treatment, after weighing up the risks and benefits of each.
This information will enable conversations between women and their surgeons about the approach that is best for them.
What’s the issue?
HPV vaccination and cervical screening have reduced the numbers of women who develop pre-cancer and cancer of the cervix. Even so, almost 23,000 women in England receive surgical treatments for pre-cancer of the cervix every year.
In some procedures, a cone-shaped portion of the cervix is removed (this is excisional surgery). Surgeons may use a cold knife (cold knife conisation), laser (laser conisation) or a heated wire loop (loop excision). Cold knife and laser procedures remove more tissue than loop excision and are commonly done under general anaesthetic. Loop excision is the most common surgical treatment for cervical pre-cancer and is often carried out under local anaesthetic.
Other procedures (called ablative), destroy only the portion of the cervix containing the abnormal cells and less tissue is removed. Surgeons may use a laser (laser ablation), freezing (cryotherapy) or a heated probe (cold coagulation).
Immediate complications from surgery are mild and uncommon. However, some procedures have been linked to increased risk of premature birth (less than 37 weeks) in subsequent pregnancies. Previously, all these procedures were thought to be equally effective treatments for pre- and early cancer. More recent evidence has suggested that cancer recurrence may be more likely when less tissue is removed.
This study explored the trade-off between cancer prevention, and the risk of premature birth associated with each treatment.
The review included studies exploring risk of recurrence (of pre- or early cancer) and preterm birth after different surgical treatments. Only 1 in 4 studies were randomised controlled trials. 71 studies (19,000 women in all) assessed treatment success or failure; 29 studies (69,000 women in all) looked at premature birth after treatment. Researchers compared the risks of different types of treatment.
In general, surgery that removed more tissue from the cervix was more successful in preventing cancer but increased the risk of premature birth. The study found that, regardless of the severity of pre-cancer:
- cold knife conisation had 7% chance of cancer recurrence and 16% chance of premature birth
- laser conisation had 6% chance of cancer recurrence and 13% chance of premature birth.
The most common UK treatment had intermediate results. The study found that:
- loop excision had 10% chance of cancer recurrence and 11% chance of preterm birth.
Surgery that removed the least tissue was least successful in treating cancer, but had the lowest chance of a future premature birth. The study found that:
- laser ablation had 16% chance of pre-cancer recurrence and 8% chance of preterm birth
- cryotherapy had 17% chance of pre-cancer recurrence and 8% chance of preterm birth.
Studies suggested that cold coagulation had 11% chance of pre-cancer recurrence and 6% chance of preterm birth. However, the researchers warned that these results might not be reliable because the evidence was limited.
Why is this important?
These findings provide helpful information for doctors and patients, to help them decide which technique is most suitable for each woman. The standard UK treatment, loop excision, offers a balance between the risk of pre-cancer recurrence and of premature birth in future pregnancies. However, a woman’s circumstances might determine the most suitable treatment: for example her age, the extent and location of the abnormal cells in the cervix, and whether she plans to have children in the future.
The study also found that the greater the length of the removed cone, the greater the risk of premature birth, but the lower the risk of pre-cancer recurrence. Women who have had a greater length of tissue removed might therefore need closer monitoring in subsequent pregnancies.
The researchers caution that many of the studies included in the analysis were observational and at high risk of bias.
The researchers have worked with associations and groups to standardise the way in which the length of removed tissue is recorded. This information could be used to guide counselling and future pregnancy care for women who have had cervical cancer surgery.
The researchers have analysed the value for money of the different treatment methods. The results are expected to be published soon.
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This Alert is based on Kyrgiou M, Athanasiou A, Cieslak-Jones D. Comparative effectiveness and risk of preterm birth of local treatments for cervical intraepithelial neoplasia and stage IA1 cervical cancer: a systematic review and network meta-analysis. Lancet Oncology 2022; 23: 1097–108.
Funding: This research was supported by NIHR Research for Patient Benefit.
Conflicts of Interest: One author has received funding from a biotech company. Other authors declare no competing interests. Full details can be found on the original research paper.
Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) at the time of publication. They do not necessarily reflect the views of the NHS, the NIHR or the Department of Health and Social Care.