Sentinel node biopsy for lymph nodal staging of uterine cervix cancer: A systematic review and meta-analysis of the pertinent literature

Abstract

Background

We reviewed the available literature on the accuracy of sentinel node mapping in the lymph nodal staging of uterine cervical cancers.

Methods

MEDLINE and Scopus were searched by using “sentinel AND (cervix OR cervical)” as key words. Studies evaluating the accuracy of sentinel node mapping in the lymph nodal staging of uterine cervical cancers were included if enough data could be extracted for calculation of detection rate and/or sensitivity.

Results

Sixty-seven studies were included in the systematic review. Pooled detection rate was 89.2% [95% CI: 86.3–91.6]. Pooled sensitivity was 90% [95% CI: 88–92]. Sentinel node detection rate and sensitivity were related to mapping method (blue dye, radiotracer, or both) and history of pre-operative neoadjuvant chemotherapy. Sensitivity was higher in patients with bilaterally detected pelvic sentinel nodes compared to those with unilateral sentinel nodes. Lymphatic mapping could identify sentinel nodes outside the routine lymphadenectomy limits.

Conclusion

Sentinel node mapping is an accurate method for the assessment of lymph nodal involvement in uterine cervical cancers. Selection of a population with small tumor size and lower stage will ensure the lowest false negative rate. Lymphatic mapping can also detect sentinel nodes outside of routine lymphadenectomy areas providing additional histological information which can improve the staging. Further studies are needed to explore the impact of sentinel node mapping in fertility sparing surgery and in patients with history of neoadjuvant chemotherapy.

Introduction

In surgically treated patients with early cervical cancer, lymph nodal status is the most important predictor of disease free and overall survival.1, 2, 3 Pelvic lymphadenectomy has long been considered the standard procedure of lymph nodal staging in early cervical cancer. However, complete pelvic lymph node dissection is associated with several complications and morbidities such as lymphedema, lymphocele formation, prolonged surgical duration, etc.⁴ On the other hand, prevalence of lymph nodal involvement in early stage cervical cancer is estimated to be approximately 15–20%. This means that the majority of early cervical cancer patients who undergo pelvic lymph node dissection will not gain any benefit from the procedure whilst being subjected to considerable complications and morbidities.⁵

The concept of the sentinel node as the first node(s) receiving lymphatic drainage of a tumor has attracted the attention of surgical oncologists since its introduction two decades ago. As the sentinel lymph node is the first site of tumor metastasis, pathological condition of sentinel node should reflect metastatic disease in the other lymph nodes of the basin (non-sentinel lymph nodes). Therefore, lymphatic mapping and sentinel lymph node biopsy can make full regional lymphadenectomy unnecessary in a large number of patients.⁶

In gynecological cancers, sentinel node mapping has long been used with favorable results.7, 8 Several multicenter studies have also been published on sentinel node mapping in cervical cancer including SENTICOL,⁹ AGO,¹⁰ and an international multicenter cohort study.¹¹

Despite an exhaustive body of literature regarding sentinel node mapping in cervical cancer, no comprehensive systematic review has been published over recent years to cover this topic. Factors associated with sentinel node detection rate and the sensitivity of this procedure in cervical cancer have not before been addressed in detail. In the current study, we reviewed the available literature regarding sentinel node mapping in cancers of the uterine cervix, presenting the results in systematic review and meta-analysis formats.