Identifying safe diagnostic algorithms for sentinel lymph node mapping in high-risk endometrial cancer: The SENTIREC-endo study.

INTRODUCTION: It is unclear if sentinel node (SLN) mapping can replace pelvic- (PLD) and paraaortic lymphadenectomy (PALD) for high-risk endometrial cancer (EC). A diagnostically safe surgical algorithm, taking failed mapping cases into account, is not defined. We aimed to investigate the diagnostic accuracy of SLN mapping algorithms in women with exclusively high-risk EC. METHODS: We undertook a prospective national diagnostic cohort study of SLN mapping in women with high-risk EC from March 2017 to January 2023. The power calculation was based on the negative predictive value (NPV). Women underwent SLN mapping, PLD and PALD besides removal of suspicious and any FDG/PET-positive lymph nodes. Accuracy analyses were performed for five algorithms. RESULTS: 170/216 included women underwent SLN mapping, PLD and PALD and were included in accuracy analyses. 42/170 (24.7%) had nodal metastasis. The algorithm SLN and PLD in case of failed mapping, demonstrated a sensitivity of 86% (95% CI 74-100) and an NPV of 96% (95% CI 91-100). The sensitivity increased to 93% (95% CI 83-100) and the NPV to 98% (95% CI 94-100) if PLD was combined with removal of any PET-positive lymph nodes. Equivalent results were obtained if PLD and PALD were performed in non-mapping cases; sensitivity 93% (95% CI 83-100) and NPV 98% (95% CI 95-100). CONCLUSION: SLN-mapping is a safe staging procedure in women with high-risk EC if strictly adhering to a surgical algorithm including removal of any PET-positive lymph nodes independent of location and PLD or PLD and PALD in case of failed mapping.

Sentinel lymph node mapping for endometrial and cervical cancer in Denmark.

INTRODUCTION: This was a surgical pilot study to systematically introduce the technique of sentinel lymph node (SLN) mapping in women with early-stage stage cervical cancer (CC) and endometrial cancer (EC) in Denmark. The study aimed to facilitate structured surgical training to ensure surgeon proficiency in SLN mapping. The study precedes two national prospective studies on the oncological safety and correct patient selection for SLN mapping in CC and EC. METHODS: The study was conducted at four gynaecological cancer centres at Odense and Aarhus University Hospital, Rigshospitalet and Herlev Hospital, between September 2016 and August 2019. All centres went through a protocolled introduction to the surgical technique, pelvic lymphatic drainage, pathological ultra-staging and data entry. A criterion of a total (uni- and bilateral) SLN detection of > 80%, based on 30 SLN mappings was set. RESULTS: The four centres performed 140 (range: 30-46) procedures. The total SLN detection rate was 91.3% with bilateral SLN detection in 68.8% and unilateral SLN detection in 22.5% of cases. The cumulated total SLN detection rate at three centres was above the pre-set 80% criterion from the beginning of inclusion, whereas one centre reached the criterion after 20 procedures. CONCLUSIONS: In this study, all centres demonstrated international-level SLN detection rates within 30 procedures. Hence, all centres met the study criterion regarding surgeon proficiency and were eligible for the national studies. FUNDING: Eva and Henry Frænkels Fond, Frimodt-Heineke Fonden, Kong Christian X Fond. TRIAL REGISTRATION: The study was approved by the Danish Data Protection Agency (R. no.15/52037). The SENTIREC studies including this pilot study are registered with clinicaltrials.gov (NCT02825355 and NCT02820506).