Effectiveness and Risk of Preterm Birth With Local Treatments for Cervical Malignancies

Get Permission

In a systematic review and network meta-analyses reported in The Lancet Oncology, Athanasiou et al described the comparative effectiveness of and risk of preterm birth with local excisional and ablative treatments for cervical intraepithelial neoplasia and stage IA1 cervical cancer.

Study Details

The analyses included studies (through March 2022) of women with cervical intraepithelial neoplasia, glandular intraepithelial neoplasia, or stage IA1 cervical cancer treated with:

  • Excision, including cold knife conization, laser conization, and large loop excision of the transformation zone), or
  • Ablation, including radical diathermy, laser ablation, cold coagulation, and cryotherapy.

The network for preterm birth also included studies of women with untreated cervical intraepithelial neoplasia (untreated colposcopy group).

The primary outcome measures were treatment failure (defined as any abnormal histology or cytology) and preterm birth (< 37 weeks of gestation). Reference groups were the large loop excision of the transformation zone group for analysis of effectiveness, and the untreated colposcopy group for analysis of preterm birth.  

Key Findings

The network analysis for treatment failure included 19,240 participants across 71 studies (25 randomized trials) and the network analysis for preterm birth included 68,817 participants across 29 studies (2 randomized trials).

Compared with large loop excision of the transformation zone, risk of treatment failure was significantly reduced for other excisional methods including laser conization (odds ratio [OR] = 0.59, 95% confidence interval [CI] = 0.44–0.79) and cold knife conization (OR = 0.63, 95% CI = 0.50–0.81). Risk was increased for ablative techniques including laser ablation (OR = 1.69, 95% CI = 1.27–2.24) and cryotherapy (OR = 1.84, 95% CI = 1.33–2.56). No significant difference was found for cold coagulation (OR = 1.09, 95% CI = 0.68–1.74; based on two small studies). Conclusions could not be made for radical diathermy.

Compared with the untreated colposcopy group, risk of preterm birth was significantly increased for all excisional techniques, including cold knife conization (OR = 2.27, 95% CI = 1.70–3.02), laser conization (OR = 1.77, 95% CI = 1.29–2.43), and large loop excision of the transformation zone (OR = 1.37, 95% CI = 1.16–1.62). No significant differences were found for ablative methods, including laser ablation (OR = 1.05, 95% CI = 0.78–1.41), cryotherapy (OR = 1.01, 95% CI = 0.35–2.92), and cold coagulation (OR = 0.67, 95% CI = 0.02–29.15). Conclusions could not be made for radical diathermy.  

As stated by the investigators, “This evidence was based mostly on observational studies with their inherent risks of bias, and the credibility of many comparisons was low.”

The investigators concluded, “More radical excisional techniques reduce the risk of treatment failure but increase the risk of subsequent preterm birth. Although there is uncertainty, ablative treatments probably do not increase risk of preterm birth but are associated with higher failure rates than excisional techniques. Although we found large loop excision of the transformation zone to have balanced effectiveness and reproductive morbidity, treatment choice should rely on a woman’s age, size and location of lesion, and future family planning.”

Maria Kyrgiou, PhD, of the Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction-Surgery and Cancer, Imperial College London, is the corresponding author for The Lancet Oncology article.

Disclosure: The study was funded by the UK National Institute for Health and Care Research: Research for Patient Benefit. For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.