Sentinel lymph node biopsies in early stage oral and oropharyngeal carcinoma: a retrospective single-centre experience

Rate of occult metastasis in lip squamous cell carcinoma: A systematic review and meta-analysis

OBJECTIVES

The rate of occult metastasis in lip cancer is poorly studied. Management of the regional nodal basin in lip cancer is thus controversial. This study sought to understand the true rate of micrometastasis in lip cancer.

MATERIALS AND METHODS

Systematic review and meta-analysis was conducted of English language studies reporting lip cancer sentinel node biopsy results. Studies were obtained from the PubMed database between the years 2000 and 2023 using the search terms "sentinel node biopsy" and "squamous cell carcinoma." Random effect and fixed effect meta-analyses were performed.

RESULTS

Thirteen studies met inclusion criteria. Low heterogeneity was noted among the studies, as indicated by the I2 inconsistency test (I2  = 0%). The rate of occult metastasis ranged between 0 and 33% (mean 9%). A total of 189 lip sentinel node biopsies had been performed. Of these, 21 revealed occult nodal metastasis (11.1%, 95% CI 7.36%-16.44%). One step, generalized linear mixed modeling revealed the true rate of occult nodal metastasis to be 10% (95% CI (0.0504, 0.1746), p < 0.0001).

CONCLUSION

The rate of occult metastasis in lip cancer approaches the threshold for elective management of the regional nodal basin. Sentinel node biopsy is optimally suited for management of high-risk early T stage lip cancer.

Sentinel lymph node biopsy for early oral cancer - accuracy and considerations in patient selection

Sentinel lymph node biopsy (SLNB) for staging oral squamous cell carcinoma (OSCC) patients presenting with early (T1 and T2 N0) disease in preference to elective neck dissection (END) remains controversial worldwide. A retrospective analysis of 145 patients who underwent sentinel lymph node biopsy for a previously untreated early oral cancer between 2010 and 2020 was performed. The primary outcome measures were predictors of occult metastases, accuracy of SLNB and disease specific plus overall survival. The negative predictive value, the false negative rate, and sensitivity for SLNB were 97%, 7.8%, and 92%, respectively. Depth of invasion (DOI) was a significant predictor of N status, overall survival, and disease specific survival. There was a significant difference in the incidence of the neck node metastasis in patients with DOI <5mm compared to those with DOI >5mm. For tumours >5mm there was a moderate to good correlation between radiological depth on contrast enhanced computed tomography (CECT) and histopathological DOI. Preoperative estimation of DOI may be a useful tool in the counselling of patients in the selection of either SLNB or END for N staging purposes in early OSCC.

Analysis of the Efficiency and Prognostic Value of the Sentinel Node Technique in Oral Squamous Cell Carcinoma after Seven Years

Background and objectives: The purpose of this study was to analyse the diagnostic and prognostic efficiency of the sentinel lymph node biopsy technique (SLNB). Materials and Methods: This is a prospective observational study performed by the Hospital Complex in Santiago de Compostela (CHUS) in Spain, between February 2013 and June 2020. The study included 60 patients, who had been diagnosed with OSCC in stage T1/T2N0M0. Results: 10 patients (16.7%) presented with SN+ (sentinel node positive). The majority (80%) only presented subcapsular affection, however one case also presented with extracapsular affection. Using the Kaplan–Meier curves, we determined that the average survival estimation for SN− patients was 74.0 months (CI95% 67.6–80.5) and it was 45.4 months (CI95% 10.9–24.0) for SN+ patients (p = 0.002). SN+ patients presented an OR = 11.000 (CI95% 2.393–50.589, p = 0.002) for cancer-related mortality. In terms of the diagnostic performance of the SN (sentinel node) test, a 55% sensitivity, a 100% specificity, 100% PPV and a 84% NPV were obtained. The analysis using ROC (receiver operating characteristic) curves revealed an AUC = 0.671 (CI95% 0.492–0.850, p = 0.046). Conclusions: SLNB seems to be an adequate technique for the detection of hidden metastases.

Serial step sections at narrow intervals with immunohistochemistry are required for accurate histological assessment of sentinel lymph node biopsy in oral squamous cell carcinoma

BACKGROUND

Sentinel lymph node (SLN) biopsy is an accurate staging modality in early oral squamous cell carcinoma (OSCC), but its accuracy relies on labor-intensive histopathology protocols. We sought to determine whether serial step sections with immunohistochemistry (SSSIHC) at narrow intervals of the entire SLN are required to accurately exclude metastasis.

METHODS

Consecutive SLN biopsies over a 13-year period were retrospectively evaluated. If the index section was negative for carcinoma, the entire SLN was subjected to SSSIHC at 150 μm intervals. The first section level and total number of section levels to contain carcinoma were recorded.

RESULTS

One hundred and eighteen SLN+ from 90 patients were included. SSSIHC upstaged the nodal status in 19.5% of patients. Metastasis was identified in 16.7% and 10.2% beyond section levels 4 and 6, respectively. Among SLNs requiring SSSIHC, 47.5% contained carcinoma in a single section level.

CONCLUSION

SSSIHC of the entire SLN at 150 μm intervals are required to identify occult metastasis in OSCC.