MRI measurement of residual cervical length after radical trachelectomy for cervical cancer and the risk of adverse pregnancy outcomes: a blinded imaging analysis.

Objective: To determine the association between the residual cervix measured on postoperative MRI after radical vaginal trachelectomy (RVT) and adverse obstetrical outcomes.

Design: Observational study.

Setting: Referral Cancer centre.

Population: Women who conceived after RVT for cervical cancer at the Royal Marsden Hospital, London, between 1995 and 2015.

Methods: Postoperative MRI scans were analysed by three researchers. The agreement between researchers was assessed by Pearson's correlation coefficient and Bland-Altman plot. Patients were divided into two groups (<10 and ≥10 mm residual cervix) for the analysis of adverse obstetrical outcomes.

Main Outcome Measures: Late miscarriage, premature delivery, premature rupture of membranes (PROM) and chorioamnionitis.

Results: Thirty-one MRI scans were available; 29 of these women had a pregnancy that progressed beyond the first trimester. There was a strong reproducibility of the measurement of residual cervix (P < 0.001). Nineteen women (65.5%) had <10 mm residual cervix and 10 (34.5%) had ≥10 mm. Among women with <10 mm residual cervix, seven (36.8%) experienced PROM and ten (66.7%) had a preterm birth; No women with ≥10 mm residual cervix had PROM and two (22.2%) had a preterm birth (P = 0.028 and P = 0.035, respectively). Overall, there were nine (16.7%) first-trimester miscarriages, six (11.1%) late fetal losses, 12 (31.6%) preterm births and 36 (66.7%) live births. After a mean follow up of 78.1 months, 36 women were disease-free and one woman had died.

Conclusions: MRI measurements of the residual cervix are reproducible between observers. The incidence of PROM and premature delivery is higher when the residual cervix after RVT is <10 mm.

Tweetable Abstract: The risk of prematurity after RVT can be predicted from measurements of residual cervical length on postoperative MRI scan.