Non-sentinel node tumor invasion in oropharyngeal and oral cancer: risk of misdiagnosis of metastasis

Diagnostic test accuracy of sentinel lymph node biopsy in squamous cell carcinoma of the oropharynx, larynx, and hypopharynx: A systematic review and meta-analysis

The aim of this meta-analysis was to determine the diagnostic test accuracy of sentinel lymph node biopsy (SLNB) in patients with oropharyngeal, laryngeal, and hypopharyngeal squamous cell carcinoma (SCC). For this purpose, MEDLINE, EMBASE, and Web of Science were searched from inception to March 8, 2022. Included were studies evaluating diagnostic test accuracy of SLNB to identify cervical lymph node metastases with elective neck dissection or follow-up as reference. A bivariate generalized linear mixed model approach was used for the meta-analysis. Nineteen studies were eligible, evaluating 377 cases in total. The pooled estimates of sensitivity and negative predictive value were 0.93 (95% CI: 0.86-0.96) and 0.97 (95% CI: 0.94-0.98), respectively. The excellent accuracy of SLNB justifies a place in the diagnostic workup of patients with larynx and pharynx SCC. Randomized trials are required to demonstrate oncologic safety and benefits on treatment related morbidity and quality of life when omitting elective neck treatment based on SLNB.

A Systematic Review of Oral Biopsies, Sample Types, and Detection Techniques Applied in Relation to Oral Cancer Detection

Background: Early identification of the stage of oral cancer development can lead to better treatment outcomes and avoid malignant transformation. Therefore, this review aims to provide a comprehensive overview that describes the development of standardized procedures for oral sample collection, characterization, and molecular risk assessment. This can help investigators to choose the appropriate sampling method and downstream analyses for different purposes. Methods: This systematic review was conducted according to the PRISMA guidelines. Using both PubMed and Web of Science databases, four independent authors conducted a literature search between 15 and 21 June 2021. We used key search terms to broaden the search for studies. Non-conforming articles were removed using an EndNote-based and manual approach. Reviewers used a designed form to extract data. Results: This review included a total of 3574 records, after eliminating duplicate articles and excluding papers that did not meet the inclusion criteria. Finally, 202 articles were included in this review. We summarized the sampling methods, biopsy samples, and downstream analysis. The biopsy techniques were classified into tissue and liquid biopsy. The common sequential analysis of tissue biopsy includes histopathological examination such as H&E or IHC to identify various pathogenic features. Meanwhile, liquid samples such as saliva, blood, and urine are analyzed for the purpose of screening to detect mutations in cancer. Commonly used technologies are PCR, RT-PCR, high-throughput sequencing, and metabolomic analysis. Conclusions: Currently, tissue biopsies provide increased diagnostic value compared to liquid biopsy. However, the minimal invasiveness and convenience of liquid biopsy make it a suitable method for mass screening and eventual clinical adoption. The analysis of samples includes histological and molecular analysis. Metabolite analysis is rising but remains scarce.

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.

SPECT/CT lymphoscintigraphy of sentinel node(s) for superselective prophylactic irradiation of the neck in cN0 head and neck cancer patients: a prospective phase I feasibility study

Background

Clinically node negative HNSCC patients have a risk ranging between 18 and 45% of occult metastases, making prophylactic irradiation mandatory. Selective irradiation of nodal target volume based on international guidelines is practice. Anyway, about half the tumours lying in an anatomical subsite known to potentially drain bilaterally effectively do so, leading to unnecessary large volume irradiation. Moreover, 15% of the tumours show drainage outside of predicted basin, increasing the risk for potential geographical misses. Three-dimensional SPECT/CT lymphoscintigraphy (LS) of sentinel node(s) may help to individualize nodal target volume selection. This prospective phase I study explores its feasibility and the dosimetric impact.

Methods

Ten cN0 HNSCC patients eligible for definitive radiotherapy were imaged with SPECT/CT after ^99mTc nanocolloid injection around the tumour. The neck levels containing up to four hottest nodes were identified and selected for prophylactic irradiation (CTVn-LS) by volumetric modulated arc therapy. A comparative virtual planning was performed with volumes selected according to international guidelines (CTVn-IG).

Results

Migration was observed in all patients (one with gamma probe only). 2.9 sentinel nodes were detected per patient on average. In some patients, accurate localization was difficult when not using thermoplastic mask for SPECT/CT. CTVn-LS was totally encompassed by CTVn-IG in all patients but one (unpredicted drainage in retropharyngeal level). On average, CTVn-LS and related planning target volumes were two times smaller than IG ones. This led to significant dose decrease in identified organs at risk as well as remaining volume at risk.

Conclusions

SPECT/CT LS is a promising tool to individualize prophylactic node CTV in cN0 HNSCC patients eligible for definitive radiotherapy. Oncological safety must be confirmed by ongoing phase II study.

The prevalence of occult metastases in nonsentinel lymph nodes after step-serial sectioning and immunohistochemistry in cN0 oral squamous cell carcinoma

OBJECTIVES

To examine the prevalence of isolated tumor cells (ITC) and micrometastases (MM) in nonsentinel lymph nodes (NSN) using additional step-serial sectioning and immunohistochemistry (IHC) as for sentinel lymph nodes (SN).

STUDY DESIGN

Prospective, consecutive, and clinically controlled trial.

METHODS

Fifty-one patients with oral cavity squamous cell carcinoma (OSCC) T1-T2 and clinically N0 neck underwent surgical treatment including sentinel-node biopsy (SNB) assisted selective neck dissection (SND). The location of the SN was determined using dynamic and planar lymphoscintigraphy and SPECT-CT. The harvested NSN from the neck dissections underwent the same histopathologic examinations as the SN using step-serial sectioning (SSS) at 150-micron intervals. Two sections from each level were stained with hematoxylin-eosin (H&E) and cytokeratin antibodies (AE1/AE3) and examined for tumor deposits. Results were compared with the previous routine examination of the NSN.

RESULTS

A total of 403 NSN were examined with a median of 8 per patient. A total of 1/51 patients (2%) had involvement of an additional NSN not found on routine examination. This was the only lymph node with involvement not detected previously. However, this patient had metastases in SN and in another NSN detected on routine examination. The overall incidence of occult metastasis (SN + NSN) was 21.6% (11/51) as previously reported.

CONCLUSIONS

The incidence of occult metastases in NSN after additional SSS and IHC was 2%. The risk of NSN involvement would seem to be extremely low in patients with early OSCC and negative SN. This study further validates SNB as an accurate staging tool for cN0 early OSCC.

Comparative study of patients with and without sentinel lymph node biopsy (SLNB) in oral and oropharyngeal cancer: is SLNB an accurate and useful procedure?

CONCLUSION

Sentinel lymph node biopsy (SLNB) is a technique that facilitates the study of metastasis in oral and oropharyngeal cancer and reduces morbidity in patients affected by this pathology.

OBJECTIVES

Oral and oropharyngeal cancers are common and are frequently associated with spread to cervical lymph nodes. We attempted to confirm the usefulness of SLNB in patients suffering from squamous cell carcinoma of the oral cavity as a prognostic technique for lymph node prediction of micrometastatic invasion. Using surgical parameters, we compared its relevance against a retrospective group without SLNB.

PATIENTS AND METHODS

We studied a prospective group of 22 patients, 21 men and 1 woman, aged 40-83 years (mean=57.77, SD=13) in which SLNB was performed and a retrospective group of 22 patients, 19 men and 3 women, aged 34-76 years (mean=52.68, SD=11) in which SLNB was not performed. Both groups presented oral cavity tumors at clinical stages T1-T3 and radiological stage N0. SLNB consisted of preoperative lymphoscintigraphy (LG), intraoperative detection of the sentinel lymph node (SLN), and a histopathological examination following the recommendations of the Association of Directors of Anatomic and Surgical Pathology (ADASP) and the Canniesburn protocol.

RESULTS

We observed SLNs in 21 of 22 patients, with a total of 32 SLNs detected at cervical level II (65.63%), I (21.87%), and III (12.5%). SLNB displayed a sensitivity of 73% (confidence interval (CI)=0.51-0.99) and 100% specificity (CI=1). Negative and positive predictive values were 80% and 100%, respectively. SLNB significantly reduced the incidence of radical neck dissection (p=0.003), the need for recovery/resuscitation beds after surgery (p=0.002), surgical complications (p=0.034), and length of hospital stay (p=0.01).