Long-term follow up after sentinel node biopsy alone for early-stage cervical cancer

Impact of sentinel node use in lymphedema formation among gynecologic cancer patients

PURPOSE OF REVIEW

The most common surgical procedure associated with lymphedema formation is the regional lymphadenectomy. One of the advantages of sentinel node biopsy is the reduction of the risk of lymphedema formation. The purpose of this review is to collect and analyze the most relevant and recent evidence of the use of sentinel node biopsy and its implication on the development of postoperative lymphedema in gynecological cancer.

RECENT FINDINGS

The current evidence of the use of sentinel node biopsy in cervical cancer to reduce lymphedema is heterogeneous and more data is needed to establish its role.Sentinel lymph node biopsy in endometrial cancer is a staging procedure with lower surgical complications, as well as lymphedema formation; while the results of prospective trials evaluating its impact on quality of life are still lacking.Sentinel lymph node biopsy in vulvar cancer minimizes the need for extensive dissection and reduces the incidence of complications associated with overharvesting of lymph nodes such as lymphedema without compromising oncological outcomes.

SUMMARY

The prevalence of lymphedema in gynecological cancer varies based on the surgical treatment or additional therapies applied. Over the past years, one of the most important surgical modifications to decrease lymphedema formation has been implementation of sentinel lymph node technique mainly in vulvar cancer patients.

Benefits of sentinel node detection in cervical cancer

PURPOSE OF REVIEW

Sentinel lymph node biopsy (SLNB) is a widely used technique in other gynaecological tumours but has not yet been implemented as the gold standard technique for nodal staging in cervical cancer. Since the majority of evidence is derived from retrospective studies, this review aims to summarize the most recent evidence on this relevant topic.

RECENT FINDINGS

SLNB has demonstrated to be a well tolerated technique for lymph node staging in early-stage cervical cancer patients with promising future as exclusive lymph node assessment method avoiding full lymphadenectomy. Moreover, it allows ultrastaging and unfrequent drainage identification, which enables the detection of patients at a high risk of recurrence who would otherwise remain unnoticed. When compared with pelvic lymphadenectomy, SLNB is also associated with less intraoperative and postoperative complications, especially in terms of lymphedema formation.

SUMMARY

The available evidence suggests that SLNB offers numerous advantages over the standard pelvic lymphadenectomy reducing morbidity rates and increasing diagnostic accuracy. Three ongoing prospective trials will likely answer the controversies over these questions.

Survival after sentinel lymph node biopsy for early cervical cancers: a systematic review and meta-analysis

BACKGROUND

Sentinel lymph node biopsy represents an alternative to pelvic lymphadenectomy for lymph node staging of early-stage cervical carcinoma, but prospective evidence on long-term oncological safety of sentinel lymph node biopsy alone versus pelvic lymphadenectomy is missing.

OBJECTIVE

To investigate, with this meta-analysis, the impact of sentinel lymph node biopsy alone versus pelvic lymphadenectomy on survival for patients with early-stage cervical cancer.

METHODS

A systematic literature review was performed. We excluded studies in which pelvic lymphadenectomy was systematically performed after every sentinel lymph node biopsy, including only articles where pelvic lymphadenectomy was performed because sentinel lymph node biopsy was not conclusive. A meta-analysis was carried out combining 5-year disease-free survival and overall survival rates with a random and fixed effect model. Heterogeneity was tested using the Cochran Χ2 test and quantified with Higgins information I2.

RESULTS

The search of databases and registers found 927 items and six articles (two retrospective and four prospective). The median time of follow-up was 34.8 months (range 13-53). Overall common effect disease-free survival was 98% while random effect disease-free survival was 94%. Overall heterogeneity was 77%. A subgroup analysis was applied, dividing studies into one group including sentinel lymph node biopsy negative data only (common effect disease-free survival 91%; random effect disease-free survival 90%), and one group with a negative and positive sentinel lymph node biopsy (common effect disease-free survival 98%; random effect disease-free survival 96%). In the analysis of overall survival, positive and negative sentinel lymph node biopsy cases were examined together (common and random effect overall survival 99%). Ultrastaging did not affect disease-free survival (common and random effect disease-free survival 92% in the ultrastaging group vs common effect disease-free survival 99% and random effect disease-free survival 96% in the non-ultrastaging group).

CONCLUSIONS

Both 5-year disease-free survival and overall survival rate after sentinel lymph node biopsy alone are higher than 90% and do not differ from pelvic lymphadenectomy survival data. Ultrastaging did not impact survival.

Development of novel tracers for sentinel node identification in cervical cancer

Indocyanine green (ICG) with near-infrared (NIR) fluorescence imaging is used for lymphatic mapping. However, binding of ICG to blood proteins like serum albumin can shorten its retention time in sentinel lymph nodes (SLNs). Here, we investigated the efficacy and safety of a new fluorescence tracer comprising phytate and liposome (LP)-encapsulated ICG. Coadministration of phytate with LP containing phosphatidic acid promotes chelation mediated by Ca2+ in bodily fluids to enhance SLN retention. Uniformly sized LPs (100 nm) encapsulating ICG under conditions that minimized fluorescence self-quenching during storage were produced. We analyzed the behavior of the new tracer (ICG-phytate-LP) and control tracers (ICG and ICG-LP) in the lymphatic flow of mice in terms of lymph node retention time. We also tested lymphatic flow and safety in pigs that have a more human-like lymphatic system. LPs encapsulating stabilized ICG were successfully prepared. Mixing LP with phytate in the presence of Ca2+ increased both the particle size and negative surface charge. In mice, ICG-phytate-LP had the best lymph node retention, with a fluorescence intensity ratio that increased over 6 h and then decreased slowly over the next 24 h. In pigs, administration of ICG and ICG-phytate-LP resulted in no death or weight loss. There were no obvious differences between blood test results for the ICG and ICG-phytate-LP groups, and the overall safety was good. ICG-phytate-LP may be a useful new tracer for gynecological cancers that require time for lymph node identification due to a retroperitoneal approach.

Survival after sentinel node biopsy alone in early-stage cervical cancer: a systematic review

OBJECTIVE

To assess the oncologic outcomes of sentinel lymph node biopsy alone as part of surgical management in patients with early-stage cervical cancer.

METHODS

A systematic search of the literature was performed following the PRISMA checklist. MEDLINE (through PubMed), EMBASE, and Scopus databases were searched from June 1991 to May 2023. Studies of women with early-stage cervical cancer International Federation of Gynecology and Obstetrics (FIGO) 2009 stage IA-IIA, of any age or histology, and articles only in English language were included. After the removal of duplicates, only articles including sentinel node mapping alone compared with full pelvic lymphadenectomy were retained.

RESULTS

Four studies with a total of 2226 patients were included. Among these, 354 (15.9%) underwent sentinel lymph node biopsy alone. A total of 2210 (99.2%) patients had FIGO 2009 stage I disease and 1514 (68%) patients had squamous cell carcinoma. Median body mass index was 25.5 kg/m2 (range 23.5-27). Lymph vascular space invasion was present in 633 patients (34%) who underwent full lymphadenectomy and in 78 patients (22%) who underwent sentinel node biopsy alone. The results of the survival analysis showed that there was no significant difference in the 3-year progression-free survival rates of patients who underwent either sentinel biopsy alone or lymphadenectomy. Three-year recurrence-free survival was 93.1% (95% CI 28.3% to 64.7%) for patients who underwent sentinel node biopsy alone and 92.5% (95% CI 39.0% to 53.4%) for patients who underwent sentinel node biopsy and lymphadenectomy (p=0.773).

CONCLUSIONS

In patients with early-stage cervical cancer, performing sentinel lymph node biopsy alone compared with pelvic lymphadenectomy does not appear to independently confer a higher risk or recurrence.