Sentinel lymph node biopsy versus elective neck dissection in squamous cell carcinoma of the oral cavity with a clinically N0 neck: Systematic review and meta-analysis of prospective studies

Histopathological predictors of lymph node metastasis in oral cavity squamous cell carcinoma: a systematic review and meta-analysis

Objectives

Lymph node metastasis (LNM) is the most significant parameter affecting overall survival in patients with oral cavity squamous cell carcinomas (OCSCC). Elective neck dissection (END) is the standard of care in the early management of OCSCC with a depth of invasion (DOI) greater than 2-4 mm. However, most patients show no LNM in the final pathologic report, indicating overtreatment. Thus, more detailed indicators are needed to predict LNM in patients with OCSCC. In this study, we critically evaluate the existing literature about the risk of different histological parameters in estimating LNM.

Methods

A systematic review was conducted using PRISMA guidelines. PubMed, Web of Science, Cochrane, and Scopus were searched from inception to December 2023 to collect all relevant studies. Eligibility screening of records was performed, and data extraction from the selected studies was carried out independently. Inclusion in our systematic review necessitated the following prerequisites: Involvement of patients diagnosed with OCSCC, and examination of histological parameters related to lymph node metastasis in these studies. Exclusion criteria included animal studies, non-English articles, non-availability of full text, and unpublished data.

Results

We included 217 studies in our systematic review, of which 142 were eligible for the meta-analysis. DOI exceeding 4 mm exhibited higher risk for LNM [Risk ratio (RR) 2.18 (1.91-2.48), p<0.00001], as did perineural invasion (PNI) [RR 2.04 (1.77-2.34), p<0.00001], poorly differentiated tumors [RR 1.97 (1.61-2.42), p<0.00001], lymphovascular invasion (LVI) [RR 2.43 (2.12-2.78), p<0.00001], groups and single pattern of invasion [RR 2.47 (2.11-2.89), p<0.00001], high tumor budding [RR 2.65 (1.99-3.52), p<0.00001], tumor size over 4 cm [RR 1.76 (1.43-2.18), p<0.00001], tumor thickness beyond 4 mm [RR 2.72 (1.91-3.87), p<0.00001], involved or close margin [RR 1.73 (1.29-2.33), p = 0.0003], and T3 and T4 disease [RR 1.98 (1.62-2.41), p <0.00001].

Conclusion

Our results confirm the potential usefulness of many histopathological features in predicting LNM and highlight the promising results of others. Many of these parameters are not routinely incorporated into pathologic reports. Future studies must focus on applying these parameters to examine their validity in predicting the need for elective neck treatment.

Oncologic and functional results between sentinel lymph node biopsy and elective neck dissection in cT1/2N0 maxillary squamous cell carcinoma

OBJECTIVE

To evaluate the oncologic safety and quality of life associated with the use of sentinel lymph node biopsy (SLNB) as compared to elective neck dissection (END) in patients with cT1/2N0 maxillary squamous cell carcinoma.

METHODS

This study constituted a retrospective analysis of consecutively treated patients who underwent SLNB or END, with data collected prospectively. We analyzed the impact of the different neck procedures on regional control and disease-specific survival via the Cox model. Patients in both groups completed the University of Washington Quality of Life questionnaire.

RESULTS

We included a total of 130 patients, with 47 receiving SLNB. In all cases, the sentinel lymph node could be identified, and of these, 5 had a positive result, yielding a sensitivity of 83.3 %, a specificity of 100 %, a false negative rate of 16.7 %, and a negative predictive value of 97.6 %. The sensitivity, specificity, false negative rate, and negative predictive value of END in detecting occult metastasis were 64.3 %, 100 %, 35.7 %, and 93.2 %, respectively. In comparison to END after propensity score matching, SLNB exhibited no significant difference in its effects on regional control (p = 0.519, HR: 1.05, 95 % CI: 0.52-1.93) and disease-specific survival (p = 0.634, HR: 1.22, 95 % CI: 0.53-1.99). Patients in SLNB group showed significantly higher mean scores of shoulder and taste domains at 3 months, 6 months, and 12 months postoperatively compared to those in END group.

CONCLUSION

SLNB could act as a viable alternative to END in cT1/2N0 maxillary squamous cell carcinoma with comparable prognosis and better quality of life.

Foregoing elective neck dissection for elderly patients with oral cavity squamous cell carcinoma

OBJECTIVE

Elective neck dissection (END) improves outcomes among clinically node-negative patients with oral cavity squamous cell carcinoma (OCSCC). However, END is of questionable value, considering the potentially higher comorbidities and operative risks in elderly patients.

METHODS

A retrospective review of all patients older than 65 years of age who were treated for OCSCC at a tertiary care centre between 2005 and 2020 was conducted.

RESULTS

Fifty-three patients underwent primary tumour resection alone, and 71 had simultaneous END. Most primary tumours were located on the mobile tongue. The patients who did not undergo END had a higher mean age (81.2 vs. 75.1 years, P < 0.00001), significantly shorter surgeries, and shorter hospitalizations. Occult cervical metastases were found in 24% of the patients who underwent END. The two groups showed no significant differences in overall survival or recurrence rates. Similar results were shown in a subpopulation analysis of patients older than 75 years.

CONCLUSION

Foregoing END in elderly patients with no clinical evidence of neck metastases did not result in lower survival rates or higher recurrence rates.

Continuous innovation in precision radio-guided surgery

Since its origins, nuclear medicine has faced technological changes that led to modifying operating modes and adapting protocols. In the field of radioguided surgery, the incorporation of preoperative scintigraphic imaging and intraoperative detection with the gamma probe provided a definitive boost to sentinel lymph node biopsy to become a standard procedure for melanoma and breast cancer. The various technological innovations and consequent adaptation of protocols come together in the coexistence of the disruptive and the gradual. As obvious examples we have the introduction of SPECT/CT in the preoperative field and Drop-in probes in the intraoperative field. Other innovative aspects with possible application in radio-guided surgery are based on the application of artificial intelligence, navigation and telecare.

Prognostic study of sentinel lymph node biopsy in early-stage oral squamous cell carcinoma with computed tomography lymphography

PURPOSE

Occult metastasis is a prognostic factor for early-stage oral squamous cell carcinoma (OSCC). Sentinel lymph node (SLN) biopsy (SLNB) is a promising method to detect such metastases. The present study aimed to evaluate the diagnostic reliability of SLNB with computed tomography lymphography (CTL) for early-stage OSCC and to clarify patient outcomes after SLNB.

METHODS

The medical records of 42 patients with T1 or T2 cN0 OSCC who had undergone CTL the day before surgery were retrospectively collected and statistically analyzed.

RESULTS

SLNs were identified on CTL in 41 of 42 OSCC patients (97.6 %). Micrometastases were detected in 10 of 41 cases (24.4 %) and 11 of 65 SLNs (16.9 %) by intraoperative pathological diagnosis. Three cases showed occult metastasis within a year after the primary operation. Specificity and negative predictive value were 76.9 % and 90.3 %, respectively. The cumulative 5-year regional recurrence-free rate was 89.7 % in 31 SLNB-negative patients. Five-year overall and disease-free survival rates were 86.9 % and 70.1 %, respectively, in the 41 cases with identified SLNs.

CONCLUSION

CTL offers acceptable results and appears likely to be effective in treating early-stage OSCC patients with low-invasive surgery. Further investigation is necessary to compare radioisotope-based methods.

Urokinase-Type Plasminogen Activator Receptor (uPAR) Expression and [64Cu]Cu-DOTA-AE105 uPAR-PET/CT in Patient-Derived Xenograft Models of Oral Squamous Cell Carcinoma

PURPOSE

[64Cu]Cu-DOTA-AE105 urokinase-type plasminogen activator receptor (uPAR)-PET/CT is a novel and promising imaging modality for cancer visualization, although it has not been tested in head and neck cancer patients nor in preclinical models that closely resemble these heterogenous tumors, i.e., patient-derived xenograft (PDX) models. The aim of the present study was to establish and validate oral squamous cell carcinoma (OSCC) PDX models and to evaluate [64Cu]Cu-uPAR-PET/CT for tumor imaging in these models.

PROCEDURES

PDX flank tumor models were established by engrafting tumor tissue from three patients with locally advanced OSCC into immunodeficient mice. [64Cu]Cu-DOTA-AE105 was injected in passage 2 (P2) mice, and [64Cu]Cu-uPAR-PET/CT was performed 1 h and 24 h after injection. After the last PET scan, all animals were euthanized, and tumors dissected for autoradiography and immunohistochemical (IHC) staining.

RESULTS

Three PDX models were established, and all of them showed histological stability and unchanged heterogenicity, uPAR expression, and Ki67 expression through passages. A significant correlation between uPAR expression and tumor growth was found. All tumors of all models (n=29) showed tumor uptake of [64Cu]Cu-DOTA-AE105. There was a clear visual concordance between the distribution of uPAR expression (IHC) and [64Cu]Cu-DOTA-AE105 uptake pattern in tumor tissue (autoradiography). No significant correlation was found between IHC (H-score) and PET-signal (SUVmax) (r=0.34; p=0.07).

CONCLUSIONS

OSCC PDX models in early passages histologically mimic donor tumors and could serve as a valuable platform for the development of uPAR-targeted imaging and therapeutic modalities. Furthermore, [64Cu]Cu-uPAR-PET/CT showed target- and tumor-specific uptake in OSCC PDX models demonstrating the diagnostic potential of this modality for OSCC patients.

Diagnostic Accuracy of Up-Front PET/CT and MRI for Detecting Cervical Lymph Node Metastases in T1-T2 Oral Cavity Cancer-A Prospective Cohort Study

The diagnostic accuracy of up-front 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for detecting cervical lymph node metastases in patients with T1-T2 oral squamous cell carcinoma is reported with large discrepancies across the literature. We investigated the sensitivity, specificity, positive and negative predictive value, and accuracy of up-front PET/CT for detecting cervical lymph node metastases in this patient group and compared the performance to magnetic resonance imaging (MRI). In this prospective cohort study, 76 patients with T1-T2 oral squamous cell carcinoma underwent an up-front PET/CT and MRI at the Odense University Hospital from September 2013 to February 2016. Sentinel node biopsy and elective neck dissection were used for histopathological verification of the imaging modalities. Up-front PET/CT was significantly more sensitive than neck MRI (74% vs. 27%, p = 0.0001), but less specific (60% vs. 88%, p = 0.001). The accuracy of PET/CT and neck MRI was comparable (66% vs. 63%, p = 0.85), the PPV was slightly in favor of neck MRI (56% vs. 62%, p = 0.73), the NPV was slightly in favor of PET/CT (77% vs. 63%, p = 0.16). Neither PET/CT nor neck MRI should stand alone for N-staging T1-T2 oral cavity cancer.

Imaging of Neck Nodes in Head and Neck Cancers - a Comprehensive Update

Cervical lymph node metastases from head and neck squamous cell cancers significantly reduce disease-free survival and worsen overall prognosis and, hence, deserve more aggressive management and follow-up. As per the eighth edition of the American Joint Committee on Cancer staging manual, extranodal extension, especially in human papillomavirus-negative cancers, has been incorporated in staging as it is important in deciding management and significantly impacts the outcome of head and neck squamous cell cancer. Lymph node imaging with various radiological modalities, including ultrasound, computed tomography and magnetic resonance imaging, has been widely used, not only to demonstrate nodal involvement but also for guided histopathological evaluation and therapeutic intervention. Computed tomography and magnetic resonance imaging, together with positron emission tomography, are used widely for the follow-up of treated patients. Finally, there is an emerging role for artificial intelligence in neck node imaging that has shown promising results, increasing the accuracy of detection of nodal involvement, especially normal-appearing nodes. The aim of this review is to provide a comprehensive overview of the diagnosis and management of involved neck nodes with a focus on sentinel node anatomy, pathogenesis, imaging correlates (including radiogenomics and artificial intelligence) and the role of image-guided interventions.

Contrast-enhanced and indirect computed tomography lymphangiography accurately identifies the cervical lymphocenter at risk for metastasis in pet dogs with spontaneously occurring oral neoplasia

For dogs with oral tumors, cervical lymph node (LN) metastasis alters treatment and prognosis. It is therefore prudent to make an accurate determination of the clinical presence (cN+ neck) or absence (cN0 neck) of metastasis prior to treatment. Currently, surgical LN extirpation with histopathology is the gold standard for a diagnosis of metastasis. Yet, recommendations to perform elective neck dissection (END) for staging are rare due to morbidity. Sentinel lymph node (SLN) mapping with indirect computed tomography lymphangiography (ICTL) followed by targeted biopsy (SLNB) is an alternative option to END. In this prospective study, SLN mapping followed by bilateral END of all mandibular LNs (MLNs) and medial retropharyngeal LNs (MRLNs) was performed in 39 dogs with spontaneously occurring oral neoplasia. A SLN was identified by ICTL in 38 (97%) dogs. Lymphatic drainage patterns were variable although most often the SLN was identified as a single ipsilateral MLN. In the 13 dogs (33%) with histopathologically confirmed LN metastasis, ICTL correctly identified the draining lymphocentrum in all (100%). Metastasis was confined to the SLN in 11 dogs (85%); 2 dogs (15%) had metastasis beyond the SLN ipsilaterally. Contrast enhanced CT features had good accuracy in predicting metastasis, with short axis measurements less than 10.5 mm most predictive. ICTL imaging features alone were unable to predict metastasis. Cytologic or histopathologic SLN sampling is recommended prior to treatment to inform clinical decision-making. This is the largest study to show potential clinical utility of minimally invasive ICTL for cervical LN evaluation in canine oral tumors.

Role of sentinel lymph node biopsy for oral squamous cell carcinoma: Current evidence and future challenges

Sentinel lymph node biopsy (SLNB) has been used across oncological specialties for prognostication, staging, and identification of occult nodal metastasis. Recent studies demonstrated the potential clinical utility of SLNB in oral cavity squamous cell carcinoma (OCSCC). Elective neck dissection is the current standard of care in early management of OCSCC with depth of invasion greater than 2-4 mm; however, majority of patients ultimately do not have nodal disease on final pathology. SLNB is an alternative procedure widely adopted in early cancer management in many oncological subspecialities. Several considerations such as depth of invasion, nodal mapping, histopathology methods, operator variability, postoperative complications, and advancement in preoperative and intraoperative imaging technology can guide the appropriate application to SLNB in OCSCC. The aim of this review is to discuss the current evidence for SLNB in the treatment of early stage OCSCC, imaging technologies that support SLNB procedures, and studies that are currently underway.

Sentinel lymph node biopsy in high-risk cutaneous squamous cell carcinoma of the head and neck: Systematic review and meta-analysis

The aim of our study was to better define the role of sentinel lymph node biopsy (SLNB) in high-risk cutaneous squamous cell carcinoma of the head and neck (cSCCHN). A systematic review and meta-analysis was performed according to the PRISMA statement. Seven-hundred and five patients were included from 20 studies. The pooled SLN identification rate was 98.8% (95%CI: 97.0-99.8). The median number of SLN excised was 3.6 (n = 371, 95%CI: 2.0-4.4). The pooled SLNB positive rate and cumulative regional recurrence rate (RRR) in negative SLNB were 5.6% (95%CI: 2.6-9.6) and 2.9% (95%CI: 0.5-7.2), respectively. The high SLN identification rate demonstrates SLNB feasibility in cSCCHN. The low SLNB positive rate and the relatively high RRR raise some doubts concerning its clinical utility. Further studies are mandatory to define predictors of lymph node metastases able to better select patients that may benefit from a SLNB.

Predictive factors for false negatives following sentinel lymph node biopsy in early oral cavity cancer

Prophylactic elective neck dissection (ND) with navigation surgery using radioisotope-based sentinel lymph node biopsy (SLNB) is non-inferior to elective ND in terms of survival but has an advantage in postoperative functional disability. We conducted a subgroup analysis to identify predictive factors for false-negative (FN)-SLNB in patients with early oral cavity cancer. This study is a supplementary analysis using the dataset of a previously reported randomized clinical trial on SLN navigation surgery for oral cancers. This study investigated the association of clinical and SLN-related factors with false-negative cases in the SLNB group. From 2011 to 2016, 275 patients were enrolled and randomly assigned to the ND and SLNB study groups, with 134 patients assigned to the SLNB group. In the SLNB group, seven cases with negative SLNs and neck recurrences were judged as FN-SLNBs according to the general definition. The number of detected SLNs with and without adjusting for the propensity score was significantly associated with FNs in the logistic analysis. FN-SLNB was associated with the number of identified SLNs, suggesting the need for careful postoperative monitoring for neck recurrence in patients with one or two identified SLNs after acquiring sufficient experience in the identification technique.

Centralised pathology service for sentinel node biopsy in oral cavity cancer: The Southeast England Consortium experience

BACKGROUND

Sentinel lymph node biopsy is an increasingly recognised option for accurate staging and subsequent management of the clinically negative neck in early stage oral cavity squamous cell carcinoma. However, the technique is currently underused due to several logistic constraints including increased burden on pathology services. Here, we describe the feasibility of an outsourced centralised pathology processing and reporting service for sentinel lymph node biopsies in oral cavity squamous cell carcinoma.

PATIENTS AND METHODS

The Southeast England Consortium comprises four surgical centres utilising a central pathology service. Consecutive cases between January 2016 and February 2020 were retrospectively evaluated for survival outcomes and laboratory turnaround times.

RESULTS

Twenty-eight per cent from a cohort of 139 patients had positive sentinel nodes. There was a trend towards greater overall, disease-free and disease-specific survival (OS, DFS and DSS, respectively) in sentinel node negative compared to sentinel node positive patients, but these differences were not statistically significant. The sensitivity, negative predictive value and false negative rate were 92.8%, 97.0% and 6.8%, respectively. The mean and mode laboratory TAT were 5 and 4 working days, respectively.

CONCLUSION

An outsourced centralised pathology service is a feasible option to widen the availability of sentinel node biopsy in oral cavity squamous cell carcinoma.

Systematic review and meta-analysis of randomized controlled trials comparing elective neck dissection versus sentinel lymph node biopsy in early-stage clinically node-negative oral and/or oropharyngeal squamous cell carcinoma: Evidence-base for practice and implications for research

PURPOSE

Management of clinically node-negative (N0) neck in early-stage (T1-T2) oral and/or oropharyngeal squamous cell carcinoma (OOSCC) has been controversial. The purpose of this systematic review and meta-analysis was to compare sentinel lymph node biopsy (SLNB) with elective neck dissection (END) in early-stage OOSCC.

METHODS

Studies comparing SLNB versus END in early-stage clinically node-negative OOSCC were identified using validated search strategy. To be considered eligible, trials had to include patients with early-stage, clinically node-negative OOSCC who had been randomly assigned to either SLNB or END. Primary outcome of interest was overall survival (OS), while secondary outcomes included isolated neck nodal recurrence (NNR), loco-regional recurrence (LRR), and neck-shoulder function. Outcome data was pooled using random-effects model and reported as hazard ratio (HR) or risk ratio (RR) with 95% confidence interval (CI). Any p-value < 0.05 was considered statistically significant.

RESULTS

A total of 608 patients from three trials comparing SLNB versus END in early-stage clinically node-negative OOSCC were included. The pooled HR of death for SLNB versus END was 1.18 (95% CI: 0.79-1.78, p = 0.41) which was not statistically significant. The rates of isolated NNR (pooled RR = 1.11, 95% CI: 0.69-1.80, p = 0.66) and LRR (pooled RR = 1.18, 95% CI: 0.81-1.72, p = 0.39) were also similar. Pooled analysis of the neck-shoulder function significantly favoured SLNB arm (pooled RR = 1.21, 95% CI: 1.12-1.32, p < 0.00001).

CONCLUSION

There is low-certainty evidence that SLNB is oncologically non-inferior to END and is associated with potentially lesser functional morbidity making it an emerging alternative standard of care in patients with early-stage clinically node-negative OOSCC.