Lymphatic mapping and sentinel node biopsy in squamous cell carcinoma of the vulva: Systematic review and meta-analysis of the literature

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.

Sentinel lymph node biopsy in vulval cancer: systematic review and meta-analysis

BACKGROUND

The purpose of this study was to determine the accuracy of sentinel lymph node (SLN) biopsy with technetium 99 (99mTc) and/or blue dye-enhanced lymphoscintigraphy in vulval cancer.

METHODS

Sensitive searches of databases were performed upto October 2013. Studies with at least 75% of women with FIGO stage IB or II vulval cancer evaluating SLN biopsy with 99mTc, blue dye or both with reference standard of inguinofemoral lymphadenectomy (IFL) or clinical follow-up were included. Meta-analyses were performed using Meta-Disc version 1.4.

RESULTS

Of the 2950 references, 29 studies (1779 women) were included; most of them evaluated 99mTc combined with blue dye. Of these, 24 studies reported results for SLN followed by IFL, and 5 reported clinical follow-up only for SLN negatives. Pooling of all studies was inappropriate because of heterogeneity. Mean SLN detection rates were 94.0% for 99mTc, 68.7% for blue dye and 97.7% for both. SLN biopsy had pooled sensitivity of 95% (95% CI 92-98%) with negative predictive value (NPV) of 97.9% in studies using 99mTc/blue dye, ultrastaging and immunohistochemistry with IFL as reference. Pooled sensitivity for SLN with clinical follow-up for SLN-negatives was 91% (85-95%) with NPV 95.6%. Patients undergoing SLN biopsy experienced less morbidity than those undergoing IFL.

CONCLUSIONS

Sentinel lymph node biopsy using 99mTC, blue dye and ultrastaging with immunohistochemistry is highly accurate when restricted to carefully selected patients, within a rigorous protocol, with close follow-up and where sufficient numbers for learning curve optimisation exist. Patients must make an informed choice between the slightly higher groin recurrence rates of SLN biopsy vs the greater morbidity of IFL.

Prognostic significance of sentinel lymph node mapping in Merkel cell carcinoma: systematic review and meta-analysis of prognostic studies

Aim. To assess through a systematic review and meta-analysis of the literature the prognostic implication of sentinel lymph node mapping in Merkel cell carcinoma (MCC). Materials and Methods. PubMed and SCOPUS databases were searched by using “Merkel AND sentinel” as keywords. All studies with prognostic information regarding SLN mapping in cN0 MCC patients were included. Hazard ratio (HR) for overall survival (OS) and disease free survival (DFS) was used as effect size. Results. SLN biopsy predicted better DFS and OS as compared to the nodal observation in cN0 MCC patients (pooled HR for DFS: 1.61 (95% CI: 1.05–2.46), P = 0.028; pooled HR for OS: 1.08 (95% CI: 0.55–2.10), P = 0.8). Pathologically negative SLN (SLN−) patients had better OS (pooled HR: 4.42 (95% CI: 1.82–10.7), P = 0.0009) and DFS (pooled HR: 2.58 (95% CI: 1.78–3.73)) as compared to SLN+ patients. Conclusion. SLN mapping can provide strong prognostic information regarding OS and DFS in cN0 MCC patients. More importantly, SLN mapping can improve DFS and possibly OS in cN0 MCC patients as compared to nodal observation. As MCC is a rare tumor, large multicenter prospective studies are still needed to validate the survival benefit of SLN mapping.

Long-term follow-up of vulvar cancer patients evaluated with sentinel lymph node biopsy alone

OBJECTIVE

The objective of this study was to examine SLN evaluation alone in women with squamous cell carcinoma (SCC) of the vulva and evaluate the inguinal recurrence and complication rates.

METHODS

An IRB approved prospective study enrolled patients with SCC of the vulva. Peritumoral injection of Tc-99 sulfur colloid and blue dye was used to identify SLNs intraoperatively. Patients with negative SLN for metastasis were followed clinically without further treatment. Patients with metastasis to a SLN underwent full groin node dissection followed by standard treatment protocols.

RESULTS

A total of 73 women were enrolled onto protocol with 69 patients undergoing SLN dissection. Mean age was 66.9years (range: 29-91) with 47 stage I, 12 stage II, 9 stage III, 2 stage IV and 3 unstaged patients. SLN dissections were successful in 63 patients. Of the 111 groins evaluated with a SLN dissection 93% had a SLN identified with an average of 2 SLN per groin. There were 92 groins with negative SLN and 11 groins with positive SLN. 57 patients had negative SLN and underwent conservative management with the median follow-up of 58.3months. Three patients experienced groin recurrences (2 unilateral, 1 bilateral) for a recurrence rate of 5.2% (3/57). The complication rate for the inguinal incisions was 17.5% (1 cellulitis, 1 abscess, 2 lymphoceles, 5 lymphedema and leg pain).

CONCLUSIONS

Isolated SLN dissection alone has a low inguinal recurrence rate with decreased complications and should be considered as an option for women with SCC of the vulva.

Sentinel lymph node detection and accuracy in vulvar cancer: Experience of a tertiary center in Turkey

OBJECTIVE

To explore the accuracy of sentinel lymph node (SLN) dissection in predicting regional lymph node status by using either only Technetium-99m-labelled (Tc-99m) or in combination with a blue dye in patients with squamous cell cancer of vulva.

MATERIAL AND METHODS

Twenty-one patients who had T1 (≤2 cm) or T2 (>2cm) tumors that did not encroach into the urethra, vagina or anus were included in the study. For the first twelve patients, Tc-99m was used for SLN identification, and the combined technique was used in subsequent patients. Preoperatively, Tc-99m and a blue dye was injected intradermally around the tumor. Following SLN dissection, complete inguinofemoral lymphadenectomy was performed.

RESULTS

We could detect SLN in all 21 patients (100%) by either Tc-99m or the combined method. SLN was found to be histopathologically negative in 13 groins via Tc-99m and 10 groins via the combined method. Twenty-one of these 23 (91.3%) groin non-SLN were also negative, but in two groins, we detected metastatic non-SLN.

CONCLUSION

Although SLN dissection appears promising in vulvar cancer, false negative cases are reported in the literature. Sentinel lymph node dissection without complete lymphadenectomy does not seem appropriate for routine clinical use, since it is known that groin metastasis is fatal.