CT Lymphography Using Lipiodol® for Sentinel Lymph Node Biopsy in Early-Stage Oral Cancer

This study evaluated sentinel lymph node (SLN) identification with CT lymphography (CTL) following peritumoral administration of Lipiodol^® relative to conventional ^99mTc-nanocolloid lymphoscintigraphy (including SPECT/CT) in 10 early-stage oral cancer patients undergoing SLN biopsy. Patients first underwent early dynamic and static scintigraphy after peritumoral administration of ^99mTc-nanocolloid. Subsequently, Lipiodol^® was administered at the same injection sites, followed by fluoroscopy and CT acquisition. Finally, late scintigraphy and SPECT/CT were conducted, enabling the fusion of late CTL and SPECT imaging. The next day, designated SLNs were harvested, radiographically examined for Lipiodol^® uptake and histopathologically assessed. Corresponding images of CT, ^99mTc-nanocolloid lymphoscintigraphy and SPECT/late CTL fusion were evaluated. ^99mTc-nanocolloid lymphoscintigraphy identified 21 SLNs, of which 7 were identified with CTL (33%). CTL identified no additional SLNs and failed to identify any SLNs in four patients (40%). Out of six histopathologically positive SLNs, two were identified by CTL (33%). Radiographic examination confirmed Lipiodol^® uptake in seven harvested SLNs (24%), of which five were depicted by CTL. CTL using Lipiodol^® reached a sensitivity of 50% and a negative predictive value (NPV) of 75% (median follow-up: 12.3 months). These results suggest that CTL using Lipiodol^® is not a reliable technique for SLN mapping in early-stage oral cancer.

Unilateral versus bilateral nodal irradiation: Current evidence in the treatment of squamous cell carcinoma of the head and neck

Cancers of the head and neck region often present with nodal involvement. There is a long-standing convention within the community of head and neck radiation oncology to irradiate both sides of the neck electively in almost all cases to include both macroscopic and microscopic disease extension (so called elective nodal volume). International guidelines for the selection and delineation of the elective lymph nodes were published in the early 2000s and were updated recently. However, diagnostic imaging techniques have improved the accuracy and reliability of nodal staging and as a result, small metastases that used to remain undetected and were thus in the past included in the elective nodal volume, will now be included in high-dose volumes. Furthermore, the elective nodal areas are situated close to the parotid glands, the submandibular glands and the swallowing muscles. Therefore, irradiation of a smaller, more selected volume of the elective nodes could reduce treatment-related toxicity. Several researchers consider the current bilateral elective neck irradiation strategies an overtreatment and show growing interest in a unilateral nodal irradiation in selected patients. The aim of this article is to give an overview of the current evidence about the indications and benefits of unilateral nodal irradiation and the use of SPECT/CT-guided nodal irradiation in squamous cell carcinomas of the head and neck.

What is the role of sentinel lymph node biopsy in the management of oral cancer in 2020?

Approximately 70–80% of patients with cT1-2N0 oral squamous cell carcinoma (OSCC) ultimately prove to have no cancer in the cervical lymphatics on final pathology after selective neck dissection. As a result, sentinel lymph node biopsy (SLNB) has been adopted during the last decade as a diagnostic staging method to intelligently identify patients who would benefit from formal selective lymphadenectomy or neck irradiation. While not yet universally accepted, SLNB is now incorporated in many national guidelines. SLNB offers a less invasive alternative to elective neck dissection (END), and has some advantages and disadvantages. SLNB can assess the individual drainage pattern and, with step serial sectioning and immunohistochemistry (IHC), can enable the accurate detection of micrometastases and isolated tumor cells (ITCs). Staging of the neck is improved relative to END with routine histopathological examination. The improvements in staging are particularly notable for the contralateral neck and the pretreated neck. However, for floor of mouth (FOM) tumors, occult metastases are frequently missed by SLNB due to the proximity of activity from the primary site to the lymphatics (the shine through phenomenon). For FOM cancers, it is advised to perform either elective neck dissection or superselective neck dissection of the preglandular triangle of level I. New tracers and techniques under development may improve the diagnostic accuracy of SLNB for early-stage OSCC, particularly for FOM tumors. Treatment of the neck (either neck dissection or radiotherapy), although limited to levels I–IV, remains mandatory for any positive category of metastasis (macrometastasis, micrometastasis, or ITCs). Recently, the updated EANM practical guidelines for SLN localization in OSCC and the surgical consensus guidelines on SLNB in patients with OSCC were published. In this review, the current evidence and results of SLNB in early OSCC are presented.

Equivalence Randomized Trial to Compare Treatment on the Basis of Sentinel Node Biopsy Versus Neck Node Dissection in Operable T1-T2N0 Oral and Oropharyngeal Cancer

PURPOSE

Sentinel node (SN) biopsy is accurate in operable oral and oropharyngeal cT1-T2N0 cancer (OC), but, to our knowledge, the oncologic equivalence of SN biopsy and neck lymph node dissection (ND; standard treatment) has never been evaluated.

METHODS

In this phase III multicenter trial, 307 patients with OC were randomly assigned to (1) the ND arm or (2) the SN arm (experimental arm: biopsy alone if negative, or followed by ND if positive, during primary tumor surgery). The primary outcome was neck node recurrence-free survival (RFS) at 2 years. Secondary outcomes were 5-year neck node RFS, 2- and 5-year disease-specific survival (DSS), and overall survival (OS). Other outcomes were hospital stay length, neck and shoulder morbidity, and number of physiotherapy prescriptions during the 2 years after surgery.

RESULTS

Data on 279 patients (139 ND and 140 SN) could be analyzed. Neck node RFS was 89.6% (95% CI, 0.83% to 0.94%) at 2 years in the ND arm and 90.7% (95% CI, 0.84% to 0.95%) in the SN arm, confirming the equivalence with P < .01. The 5-year RFS and the 2- and 5-year DSS and OS were not significantly different between arms. The median hospital stay length was 8 days in the ND arm and 7 days in the SN arm (P < .01). The functional outcomes were significantly worse in the ND arm until 6 months after surgery.

CONCLUSION

This study demonstrated the oncologic equivalence of the SN and ND approaches, with lower morbidity in the SN arm during the first 6 months after surgery, thus establishing SN as the standard of care in OC.

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.

A Review of Controversial Issues in the Management of Head and Neck Cancer: A Swiss Multidisciplinary and Multi-Institutional Patterns of Care Study-Part 1 (Head and Neck Surgery)

Background: The Head and Neck Cancer Working Group of Swiss Group for Clinical Cancer Research (SAKK) has investigated the level of consensus (LOC) and discrepancy in everyday practice of diagnosis and treatment in head and neck cancer.

Materials and Methods: An online survey was iteratively generated with 10 Swiss university and teaching hospitals. LOC below 50% was defined as no agreement, while higher LOC were arbitrarily categorized as low (51–74%), moderate (75–84%), and high (≥85%).

Results: Any LOC was achieved in 62% of topics (n = 60). High, moderate and low LOC were found in 18, 20, and 23%, respectively. Regarding Head and Neck Surgery, Radiation Oncology, Medical Oncology, and biomarkers, LOC was achieved in 50, 57, 83, and 43%, respectively.

Conclusions: Consensus on clinical topics is rather low for surgeons and radiation oncologists. The questions discussed might highlight discrepancies, stimulate standardization of practice, and prioritize topics for future clinical research.

An evidence-based analysis of the management of N0 neck in patients with cancer of the parotid gland

Introduction: Management of clinically negative neck (cN0) in patients with parotid gland cancer is controversial. Treatment options can include observation, elective neck dissection or elective radiotherapy. Areas covered: We addressed the treatment options for cN0 patients with parotid gland cancer. A literature review was undertaken to determine the optimal management of this group of patients. Expert opinion: Patients with parotid carcinoma and clinically negative neck have various options for their management. The analysis of tumor stage, histology and grade is essential to better define patients at risk for occult lymph node metastasis. These patients can be managed by surgery, radiotherapy or their combination, depending on the presence of risk factors, the moment at which such risk factors are detected, patient-related clinical conditions, medical provider expertise and institutional facilities.

Contemporary use of sentinel lymph node biopsy in the head and neck

Sentinel lymph node biopsy has become a well-established and commonplace practice in many oncologic disease sites as a means to stage the regional lymphatics, avoid unnecessary surgery and decrease patient morbidity. In the head and neck, its role is well established for cutaneous melanoma with proven fidelity and survival benefit. Its role in use for other sites such as oral cavity carcinoma continues to develop with promising results from several recent trials. Although not widely adopted, the potential benefits of sentinel lymph node biopsy in the management of oral cavity carcinoma are apparent. Refinements in technology and protocols including development of novel radiopharmaceutical tracers, routine incorporation of detailed anatomic imaging, increasing surgeon experience and development of new intraoperative identification aids will likely lead to improvements in the use and accuracy of this technique.

Identification of methylation markers for the prediction of nodal metastasis in oral and oropharyngeal squamous cell carcinoma

Hypermethylation is an important mechanism for the dynamic regulation of gene expression, necessary for metastasizing tumour cells. Our aim is to identify methylation tumour markers that have a predictive value for the presence of regional lymph node metastases in patients with oral and oropharyngeal squamous cell carcinoma (OOSCC). Significantly differentially expressed genes were retrieved from four reported microarray expression profiles comparing pN0 and pN+ head-neck tumours, and one expression array identifying functionally hypermethylated genes. Additional metastasis-associated genes were included from the literature. Thus genes were selected that influence the development of nodal metastases and might be regulated by methylation. Methylation-specific PCR (MSP) primers were designed and tested on 8 head-neck squamous cell carcinoma cell lines and technically validated on 10 formalin-fixed paraffin-embedded (FFPE) OOSCC cases. Predictive value was assessed in a clinical series of 70 FFPE OOSCC with pathologically determined nodal status. Five out of 28 methylation markers (OCLN, CDKN2A, MGMT, MLH1 and DAPK1) were frequently differentially methylated in OOSCC. Of these, MGMT methylation was associated with pN0 status (P = 0.02) and with lower immunoexpression (P = 0.02). DAPK1 methylation was associated with pN+ status (P = 0.008) but did not associate with protein expression. In conclusion, out of 28 candidate genes, two (7%) showed a predictive value for the pN status. Both genes, DAPK1 and MGMT, have predictive value for nodal metastasis in a clinical group of OOSCC. Therefore DNA methylation markers are capable of contributing to diagnosis and treatment selection in OOSCC. To efficiently identify additional new methylation markers, genome-wide methods are needed.

A prospective study on sentinel lymph node biopsy in early oral cancers using methylene blue dye alone

Sentinel Lymph Node (SLN) biopsy using a combination of radioisotopes and blue dyes have a good accuracy rate in predicting subclinical neck nodal metastases in head and neck cancers. However, the limited availability of lymphoscintigraphy facilities in India requires exploration of alternative methods of SLN detection. We evaluated the feasibility of using methylene blue dye alone in detecting SLN in cN0 early oral cancers. 32 patients with cN0 early (T1, T2) oral squamous cell cancers underwent SLN biopsy using peri tumoural methylene blue dye injection. Blue dye stained (SLN) nodes were sent for frozen section analyses. Patients who had microscopic metastases in SLN underwent modified radical neck dissections and the rest underwent selective neck dissections. Paraffin sections and IHC studies were done on all nodes. SLN was identified in 29 patients (Identification rate = 90.6 %) of which SLN was positive for metastases on frozen section in 5 patients. The sensitivity, specificity and NPV of SLN with frozen section were 80 %, 95.8 % and 95.8 % respectively. IHC with cytokeratins increased the sensitivity (100 %) and NPV (100 %) at the loss of specificity (87.5 %). Methylene blue dye alone can be successfully used for SLN identification in early oral cancers with a good accuracy and sensitivity. This method will be of use especially in resource limited countries and centres where nuclear medicine facilities are not widely available. However, it has to be validated by larger randomised multi institutional trials for wider applicability. Immunohistochemistry increases the sensitivity and negative predictive value of SLN but its applicability in real time decision making is limited.

Novel diagnostic modalities for assessment of the clinically node-negative neck in oral squamous-cell carcinoma

Oral squamous-cell carcinomas arise in mucosal linings of the oral cavity and frequently metastasise to regional lymph nodes in the neck. The presence of nodal metastases is a determinant of prognosis and clinical management. The neck is staged by palpation and imaging, but accuracy of these techniques to detect small metastases is low. In general, 30-40% of patients will have occult nodal disease and will develop clinically detectable lymph-node metastases when the neck is left untreated. The choice at present is either elective treatment or careful observation followed by treatment of the neck in patients who develop manifest metastases. These unsatisfying therapeutic options have been the subject of debate for decades. Recent developments in staging of the neck, including expression profiling and sentinel lymph-node biopsy, will allow more personalised management of the neck.