Usefulness of Sentinel Lymph Node Biopsy for Oral Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

We assessed the diagnostic accuracy of sentinel lymph node biopsy (SLNB) for detecting neck nodal metastasis in early oral squamous cell carcinoma (OSCC) as an alternative to elective neck dissection.

STUDY DESIGN

A systematic search for relevant literature was conducted in the PubMed, SCOPUS, Embase, Web of Science, and Cochrane databases.

METHODS

Two reviewers individually searched the five databases up to November 2019. For studies that met inclusion criteria, data on patient diagnoses were pooled, including true positives, true negatives, false positives, and false negatives. Methodological quality was checked with the Quality Assessment of Diagnostic Accuracy Studies (version 2) tool.

RESULTS

In total, 98 observational or retrospective studies were included. The diagnostic odds ratio of SLNB was 326.165 (95% confidence interval [CI]: 231.477-459.587; I²  = 0%). The area under the summary receiver operating characteristic curve was 0.982. Sensitivity was 0.827 (95% CI: 0.804-0.848), and specificity was 0.981 (95% CI: 0.975-0.986). The correlation between sensitivity and the false positive rate was -0.076, which indicates that heterogeneity did not exist. Subgroup analyses were performed with the subgroups reference test type, publication year, and study type. No significant difference was found within the reference test type subgroup. However, differences within the publication year and study type subgroups were significant, where the retrospective study subgroup was significantly more sensitive and specific than the prospective study subgroup.

CONCLUSION

Results of this meta-analysis imply that the high specificity of SLNB supports its role as a diagnostic tool for patients with clinical tumor stage (CT)1-2 clinically negative (N0) OSCC. More studies should be done to further verify the results of this study.

LEVEL OF EVIDENCE

2a Laryngoscope, 131:E459-E465, 2021.

Augmenting camera images with gamma detector data : A novel approach to support sentinel lymph node biopsy

BACKGROUND

Squamous cell carcinoma in the head and neck region is one of the most widespread cancers with high morbidity. Classic treatment comprises the complete removal of the lymphatics together with the cancerous tissue. Recent studies have shown that such interventions are only required in 30% of the patients. Sentinel lymph node biopsy is an alternative method to stage the malignancy in a less invasive manner and to avoid overtreatment. In this paper, we present a novel approach that enables a future augmented reality device which improves the biopsy procedure by visual means.

METHODS

We propose a co-calibration scheme for axis-aligned miniature cameras with pinholes of a gamma ray collimating and sensing device and show results gained by experiments, based on a calibration target visible for both modalities.

RESULTS

Visual inspection and quantitative evaluation of the augmentation of optical camera images with gamma information are congruent with known gamma source landmarks.

CONCLUSIONS

Combining a multi-pinhole collimator with axis-aligned miniature cameras to augment optical images using gamma detector data is promising. As such, our approach might be applicable for breast cancer and melanoma staging as well, which are also based on sentinel lymph node biopsy.

Elective Neck Dissection Versus Wait-and-Watch Policy for Oral Cavity Squamous Cell Carcinoma in Early Stage: A Systematic Review and Meta-Analysis Based on Survival Data

PURPOSE

Whether elective neck dissection (END) should be adopted for patients with clinically early-stage (cT1-2N0M0) oral cavity squamous cell carcinoma (OCSCC) remains debated. The aim of this systematic review was to compare the survival benefit of END with that of the wait-and-watch policy (WW) for patients with early-stage OCSCC based on survival data.

MATERIALS AND METHODS

According to the inclusion criteria, an exhaustive search for eligible studies was conducted. The study inclusion and data extraction were performed by 2 reviewers independently. The risk of bias was assessed in duplicate using the Risk Of Bias In Nonrandomized Studies of Interventions instrument. The hazard ratio (HR) of the time-to-event data was extracted or estimated. RevMan 5.3 and STATA 15.1 were adopted for data synthesis.

RESULTS

Of the 35 studies that were included, only 5 were assessed as having a low risk of bias. Results of the meta-analyses showed END could significantly decrease neck recurrence (relative risk = 0.45; confidence interval [CI], 0.35-0.59; P < .00001) and improve disease-free survival (HR = 0.55; CI, 0.42-0.71; P < .00001), overall survival (HR = 0.75; CI, 0.64-0.86; P < .0001), and disease-specific survival (HR = 0.76; CI, 0.61-0.94; P = .01) compared with WW for patients with cT1-2N0. The subgroup analysis showed that END could decrease neck recurrence (P < .00001) and improve disease-free survival (P = .001) for patients with early-stage tongue cancer and that supraomohyoid neck dissection could decrease neck recurrence (P = .02). For patients with cT1N0, END could significantly decrease the proportion with neck recurrence (P = .0008) and improve disease-free survival (P = .0003), but the difference between overall survival and disease-specific survival did not achieve significance.

CONCLUSIONS

END can decrease recurrence and improve survival time for patients with early-stage OCSCC. More high-quality studies are needed to make a solid conclusion, especially for patients with cT1N0M0.

Sentinel node biopsy using indocyanine green in oral/oropharyngeal cancer

BACKGROUNDS

Radioactive tracer-based detection has been proposed as a standard procedure in identifying sentinel nodes for cN0 oral/oropharyngeal carcinoma. However, access to radioactive isotopes may be limited in some surgical centers, and there is potential risk of the radioactive tracers to the operators. This study was designed to evaluate the feasibility of near-infrared fluorescence imaging with indocyanine green combined with blue dye mapping in sentinel node biopsy for cN0 oral/oropharyngeal carcinoma.

METHODS

Twenty-six cases of previously untreated oral/oropharyngeal carcinoma staged cT1-2N0M0 were enrolled in this study. One milliliter of indocyanine green (5 mg/ml) and 1.5 ml of methylene blue (1 mg/ml) were injected sequentially around the primary tumor in a four-quadrant pattern before skin incision. After elevation of the platysma flap and posterior retraction of the sternocleidomastoid muscle, fluorescence images were taken with a near-infrared detector, with special attention paid to any blue-dyed lymph nodes. Lymph nodes identified first with fluorescent hot spots with or without blue dye were defined as sentinel nodes, and they were harvested and sent for pathologic study.

RESULTS

Sentinel nodes were successfully harvested in all 26 cases. The number of sentinel nodes (SNs) per case varied from 1 to 9, with an average of 3.4. Routine pathology demonstrated occult metastasis exclusively in SNs in four cases (15.4 %). No tracer-associated side effects occurred in this series.

CONCLUSIONS

Near-infrared imaging using indocyanine green combined with methylene blue mapping is a feasible and reliable new method for SN biopsy in cN0 oral/oropharyngeal carcinoma.

Reliability of Incision Biopsy for Diagnosis of Oral Verrucous Carcinoma: A Multivariate Clinicopathological Study

INTRODUCTION

Studies have reported 20 % of conventional squamous cell carcinoma in patients with verrucous carcinoma (VC), later these cancers were termed as hybrid VC. It is important to distinguish both while planning treatment since hybrid VC requires addressing regional lymphatics in addition to respective surgery. Information on odds of missing the foci of invasion on routine incision biopsy might be useful in this regard.

PATIENTS AND METHODS

Records of all the patients surgically treated for oral cancer from Jan 2010 to Oct 2013 in a Tertiary Cancer Centre was analyzed. Patients diagnosed with primary VC or Verrucous Hyperplasia on incision biopsy were included in the study. Proportion of patients undiagnosed for invasive component on incision biopsy was calculated, multivariate analysis of the sample was performed to find associated cofounders.

RESULTS

Fifty-five patients who reported with the diagnosis of VC (n = 53) or Verrucous Hyperplasia (n = 2) on incision biopsy were included in the study. Twenty-seven were diagnosed as VC and 28 as hybrid VC after excision. This corresponded to 51 % (n = 28) of cases missing invasive component on incision biopsy. VC was significantly more commonly seen in lip and in buccal mucosa, hybrid VC was more commonly seen in tongue and gingiva and this association was statistically significant (p = 0.031) in our study.

CONCLUSION

Incision biopsy is extremely unreliable to diagnose and differentiate oral Hybrid VC from VC or Verrucous Hyperplasia. Caution is required while planning treatment of these patients regarding possibility of presence of conventional squamous cell carcinoma within these tumors.

Sentinel lymph node biopsy in oral and oropharyngeal squamous cell carcinoma: current status and unresolved challenges

Because imaging with ultrasound, computed tomography, magnetic resonance imaging or positron emission tomography is unreliable for preoperative lymph node staging of early-stage oral and oropharyngeal squamous cell carcinoma (OSCC), elective neck dissection has been typically performed. The targeted sampling of sentinel lymph nodes (SLN) identified by lymphoscintigraphy and detected by gamma probe has become an effective alternative for the selection of patients for regional nodal resection. With careful consideration to technique, high SLN detection rates have been reported. Advanced techniques including intraoperative handheld gamma camera imaging and freehand single photon emission computed tomography (SPECT) are expected to increase surgical confidence in these procedures. This review gives an update on SLN biopsy in patients with OSCC including clinical standards and controversial aspects.