Sentinel lymph node biopsy in uterine cervical cancer patients: ready for clinical use? A review of the literature

Effectiveness of sentinel lymph node biopsy and bilateral pelvic nodal dissection using methylene blue dye in early-stage operable cervical cancer-A prospective study

OBJECTIVE

To evaluate the effectiveness of methylene blue dye in detecting sentinel lymph nodes (SLNs) in women with early-stage operable (defined as FIGO I-IIA) cervical cancer. It also aims to evaluate procedural challenges and accuracy.

METHOD

This prospective study, which focused on 20 women with early-stage cervical cancer, was carried out between June 2016 and December 2017. These patients had SLN mapping with methylene blue dye injections and thorough examinations, including imaging. All patients underwent radical hysterectomy and complete bilateral pelvic lymphadenectomy. No additional investigation was done on the lymph node in cases where a metastasis was found in the first H&E-stained segment of the sentinel node.

RESULT

20 patients were included in the analysis. The median age of the subjects was 53, and 95 % of them had squamous cell carcinoma. 90 % of the time, the identification of SLNs was effective, and 55 SLNs were found, of which 52.7 % were on the right side of the pelvis and 47.3 % on the left. The obturator group had the most nodes, followed by the external and internal iliac groups in descending order of occurrence. Metastasis was detected in 3 patients, resulting in a sensitivity of 100 % and a specificity of 93.75 % for SLN biopsy. Notably, no false-negative SLNs were found. Complications related to methylene blue usage included urine discoloration in 30 % of patients.

CONCLUSION

This trial highlights the promising efficacy and safety of methylene blue dye alone for SLN identification in early-stage operable cervical cancer, with a notably higher success rate. Despite limitations like a small sample size, healthcare professionals and researchers can build upon the insights from this study to enhance cervical cancer management.

Role of Dual-Staining p16/Ki-67 in the Management of Patients under 30 Years with ASC-US/L-SIL

Patients diagnosed with low-grade squamous intraepithelial lesion ((L-SIL) or atypical squamous cells of undetermined significance (ASC-US) are subjected to additional investigations, such as colposcopy and biopsy, to rule out cervical intraepithelial neoplasia 2+ (CIN 2+). Especially in young patients, lesions tend to regress spontaneously, and many human papilloma virus (HPV) infections are transient. Dual-staining p16/Ki-67 has been proposed for the triage of patients with ASC-US or L-SIL, but no prospective study addressing only this subgroup of patients has been conducted so far. We performed a prospective study including all eligible patients referred for a loop electrosurgical excision procedure (LEEP) in the Department of Obstetrics and Gynecology of Timișoara University City Hospital. HPV genotyping and dual-staining for p16/Ki-67 were performed prior to LEEP, at 6 and 12 months after LEEP. A total of 60 patients were included in the study and completed the follow-up evaluation. We analyzed the sensitivity and specificity for biopsy-confirmed CIN2+ using the 95% confidence interval (CI) of high-risk human papilloma virus (HR-HPV), dual-staining p16/Ki-67, colposcopy, and combinations of the tests on all patients and separately for the ASC-US and L-SIL groups. Dual-staining p16/Ki-67 alone or in combination with HR-HPV and/or colposcopy showed a higher specificity that HR-HPV and/or colposcopy for the diagnosis of biopsy confirmed CIN2+ in patients under 30 years. Colposcopy + p16/Ki-67 and HR-HPV + colposcopy + p16/Ki-67 showed the highest specificity in our study.

p16/Ki-67 dual staining has a better accuracy than human papillomavirus (HPV) testing in women with abnormal cytology under 30 years old

Due to a high rate of transient human papillomavirus (HPV) infection, HPV genotyping has a low specificity for high-grade cervical lesions, especially in young women. p16/Ki-67 dual immunocytochemical staining can also be used for the detection of oncogenic changes in cervical cells. Our aim was to compare the performance of p16/Ki-67 dual staining and HPV genotyping in the detection of high-grade cervical lesions in patients with atypical squamous cells of undetermined significance (ASCUS)/low-grade squamous intraepithelial lesion (LSIL) on Pap smear. We retrospectively analyzed 310 patients with ASCUS/LSIL on Pap smear, who underwent colposcopy. Among these, 161 patients with suspected lesions detected by colposcopy were referred for biopsy. HPV genotyping by LINEAR ARRAY HPV Genotyping Test (CE-IVD) and p16/Ki-67 dual staining by CINtec PLUS Cytology kit was performed prior to cervical biopsy. The overall sensitivity and specificity of HPV genotyping for the detection of cervical intraepithelial neoplasia (CIN) 2-3 was 79% and 72%, respectively in patients with ASCUS, and 85% and 64%, respectively in patients with LSIL. For p16/Ki-67 test, sensitivity and specificity rate was 66% and 93%, respectively in ASCUS and 59% and 79%, respectively in LSIL group. The specificity of p16/Ki-67 staining was significantly higher in both groups in patients aged <30 years compared to patients >30 years old (p < 0.001). Our results showed that p16/Ki-67 dual staining has a higher specificity compared to HPV genotyping, especially in patients under 30 years old. This indicates the usefulness of p16/Ki-67 testing in the triage of patients with ASCUS/LSIL and <30 years old, prior to referral for colposcopy and biopsy.

Present status of sentinel lymph node biopsy in cervical cancer

Cervical cancer is the fourth most common cancer in women, and seventh overall. This disease represents a medical, economic and social burden. In early FIGO stage patients (IA, IB1 and IIA1), nodal involvement is the most important prognostic factor. Imaging evaluation of nodal metastasis is of limited value. In order to determine lymph node involvement, allow loco-regional control of the disease, define the need for adjuvant radiotherapy and improve survival, standard surgery for early disease is radical hysterectomy with systematic pelvic lymphadenectomy. However, this surgical treatment has risks and complications: longer operative time, larger blood loss, neurovascular or ureteral injury, lower-limb lymphedema, symptomatic lymphocysts, hydronephrosis. A method that allows to define the presence of regional metastasis with less morbidity and equal or greater precision is particularly relevant. The use of the sentinel lymph node biopsy is intended to reach that purpose. The present study reviews recent literature on the role of sentinel lymph node biopsy in cervical cancer, analyzing its indications and contraindications, injection and detection techniques, tracers used, surgical and pathological approaches and its applicability in up-to-date clinical practice.

Mapping lymph nodes in cancer management - role of (99m)Tc-tilmanocept injection

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium (^99mTc) and vital blue dyes are among the most widely used enhancers for SLN mapping, although near-infrared fluorescence imaging of indocyanine green is also becoming more commonly used. ^99mTc-tilmanocept is a new synthetic radioisotope with a relatively small molecular size that was specifically developed for lymphatic mapping. Because of its small size, ^99mTc-tilmanocept quickly migrates from its site of injection and rapidly accumulates in the SLN. The mannose moieties of ^99mTc-tilmanosept facilitate its binding to mannose receptors (CD206) expressed in reticuloendothelial cells of the SLN. This binding prevents transit to second-echelon lymph nodes. In Phase III trials of breast cancer and malignant melanoma, and Phase II trials of other malignancies, ^99mTc-tilmanocept had superior identification rates and sensitivity compared with blue dye. Trials comparing ^99mTc-tilmanocept with other ^99mTc-based agents are required before it can be routinely used in clinical settings.