Finding the sentinel lymph node in early cervical cancer: When is unusual not uncommon?

OBJECTIVE

To report our institutional experience with sentinel lymph node (SLN) detection using indocyanine green for cervical cancer, in terms of detection rates, detection of SLN at unusual locations, and factors associated with unusual SLN locations. In addition, we performed a systematic review of the literature to identify factors associated with unusual SLN localizations.

METHODS

This is a retrospective cohort study of women with early-stage cervical cancer undergoing sentinel lymph node mapping between 2015 and 2019. Outcome measures were SLN detection rates, detection rates of unusual locations for SLN and risk factors for aberrant lymphatic drainage pathways. In addition, studies evaluating factors associated with unusual SLN locations in cervical cancer were assessed in a systematic review.

RESULTS

A total of 100 patients were included. The unilateral SLN detection rate was 88%, whereas the bilateral detection rate was 75%. In 37% of all patients, SLN were found in unusual locations, and in 10% of patients SLN were solely found in unusual locations. Body mass index (BMI) was associated with finding SLN in unusual locations, with unusual nodes detected in 52% of patients with BMI <25 kg/m² and in 28% of patients with BMI ≥25 kg/m². The systematic review identified three studies, identifying lower BMI, nulliparity and tumor size of >20 mm as factors associated with finding SLN at unusual locations.

CONCLUSION

Aberrant drainage sites represent a significant proportion of SLN detected in cervical cancer. Factors associated with increased rates of unusual nodal locations are a lower BMI, with a possible association with nulliparity and tumor size of >20 mm.

Balloon catheters versus vaginal prostaglandins for labour induction (CPI Collaborative): an individual participant data meta-analysis of randomised controlled trials

BACKGROUND

Induction of labour is one of the most common obstetric interventions globally. Balloon catheters and vaginal prostaglandins are widely used to ripen the cervix in labour induction. We aimed to compare the effectiveness and safety profiles of these two induction methods.

METHODS

We did an individual participant data meta-analysis comparing balloon catheters and vaginal prostaglandins for cervical ripening before labour induction. We systematically identified published and unpublished randomised controlled trials that completed data collection between March 19, 2019, and May 1, 2021, by searching the Cochrane Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and PubMed. Further trials done before March 19, 2019, were identified through a recent Cochrane review. Data relating to the combined use of the two methods were not included, only data from women with a viable, singleton pregnancy were analysed, and no exclusion was made based on parity or membrane status. We contacted authors of individuals trials and participant-level data were harmonised and recoded according to predefined definitions of variables. Risk of bias was assessed with the ROB2 tool. The primary outcomes were caesarean delivery, indication for caesarean delivery, a composite adverse perinatal outcome, and a composite adverse maternal outcome. We followed the intention-to-treat principle for the main analysis. The primary meta-analysis used two-stage random-effects models and the sensitivity analysis used one-stage mixed models. All models were adjusted for maternal age and parity. This meta-analysis is registered with PROSPERO (CRD42020179924).

FINDINGS

Individual participant data were available from 12 studies with a total of 5460 participants. Balloon catheters, compared with vaginal prostaglandins, did not lead to a significantly different rate of caesarean delivery (12 trials, 5414 women; crude incidence 27·0%; adjusted OR [aOR] 1·09, 95% CI 0·95-1·24; I²=0%), caesarean delivery for failure to progress (11 trials, 4601 women; aOR 1·20, 95% CI 0·91-1·58; I²=39%), or caesarean delivery for fetal distress (10 trials, 4441 women; aOR 0·86, 95% CI 0·71-1·04; I²=0%). The composite adverse perinatal outcome was lower in women who were allocated to balloon catheters than in those allocated to vaginal prostaglandins (ten trials, 4452 neonates, crude incidence 13·6%; aOR 0·80, 95% CI 0·70-0·92; I²=0%). There was no significant difference in the composite adverse maternal outcome (ten trials, 4326 women, crude incidence 22·7%; aOR 1·02, 95% CI 0·89-1·18; I²=0%).

INTERPRETATION

In induction of labour, balloon catheters and vaginal prostaglandins have comparable caesarean delivery rates and maternal safety profiles, but balloon catheters lead to fewer adverse perinatal events.

FUNDING

Australian National Health and Medical Research Council and Monash Health Emerging Researcher Fellowship.