Does Clearance of Positive Margins Improve Local Control in Oral Cavity Cancer? A Meta-analysis

Beneath the surface: A systematic review on intraoperative imaging techniques for deep margin assessment in oral squamous cell carcinoma

Resection margins of oral squamous cell carcinoma (SCC) are often inadequate. A systematic review on clinical intraoperative whole-specimen imaging techniques to obtain adequate deep resection margins in oral SCC is lacking. Such a review may render better alternatives for the current insufficient intraoperative techniques: palpation and frozen section analyses (FSA). This review resulted in ten publications investigating ultrasound (US), four investigating fluorescence, and three investigating MRI. Both US and fluorescence were able to image the tumor intraorally and perform ex-vivo imaging of the resection specimen. Fluorescence was also able to image residual tumor tissue in the wound bed. MRI could only be used on the ex-vivo specimen. The 95 % confidence intervals for sensitivity and specificity were large, due to the small sample sizes for all three techniques. The sensitivity and specificity of US for identifying < 5 mm margins ranged from 0 % to 100 % and 60 % to 100 %, respectively. For fluorescence, this ranged from 0 % to 100 % and 76 % to 100 %, respectively. For MRI, this ranged from 7 % to 100 % and 81 % to 100 %, respectively. US, MRI and fluorescence are the currently available imaging techniques that can potentially be used intraoperatively and which can image the entire tumor-free margin, although they have insufficient sensitivity for identifying < 5 mm margins. Further research on larger cohorts is needed to improve the sensitivity by determining cut-off points on imaging for inadequate margins. This improves the number of adequate resections of oral SCC's and pave the way for routine clinical implementation of these techniques.

Latin American Consensus on the Treatment of Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is well known as a serious health problem worldwide, especially in low-income countries or those with limited resources, such as most countries in Latin America. International guidelines cannot always be applied to a population from a large region with specific conditions. This study established a Latin American guideline for care of patients with head and neck cancer and presented evidence of HNSCC management considering availability and oncologic benefit. A panel composed of 41 head and neck cancer experts systematically worked according to a modified Delphi process on (1) document compilation of evidence-based answers to different questions contextualized by resource availability and oncologic benefit regarding Latin America (region of limited resources and/or without access to all necessary health care system infrastructure), (2) revision of the answers and the classification of levels of evidence and degrees of recommendations of all recommendations, (3) validation of the consensus through two rounds of online surveys, and (4) manuscript composition. The consensus consists of 12 sections: Head and neck cancer staging, Histopathologic evaluation of head and neck cancer, Head and neck surgery-oral cavity, Clinical oncology-oral cavity, Head and neck surgery-oropharynx, Clinical oncology-oropharynx, Head and neck surgery-larynx, Head and neck surgery-larynx/hypopharynx, Clinical oncology-larynx/hypopharynx, Clinical oncology-recurrent and metastatic head and neck cancer, Head and neck surgery-reconstruction and rehabilitation, and Radiation therapy. The present consensus established 48 recommendations on HNSCC patient care considering the availability of resources and focusing on oncologic benefit. These recommendations could also be used to formulate strategies in other regions like Latin America countries.

Development and validation of a cadaveric porcine Pseudotumor model for Oral Cancer biopsy and resection training

OBJECTIVE

The gold standard of oral cancer (OC) treatment is diagnostic confirmation by biopsy followed by surgical treatment. However, studies have shown that dentists have difficulty performing biopsies, dental students lack knowledge about OC, and surgeons do not always maintain a safe margin during tumor resection. To address this, biopsies and resections could be trained under realistic conditions outside the patient. The aim of this study was to develop and to validate a porcine pseudotumor model of the tongue.

METHODS

An interdisciplinary team reflecting various specialties involved in the oncological treatment of head and neck oncology developed a porcine pseudotumor model of the tongue in which biopsies and resections can be practiced. The refined model was validated in a final trial of 10 participants who each resected four pseudotumors on a tongue, resulting in a total of 40 resected pseudotumors. The participants (7 residents and 3 specialists) had an experience in OC treatment ranging from 0.5 to 27 years. Resection margins (minimum and maximum) were assessed macroscopically and compared beside self-assessed margins and resection time between residents and specialists. Furthermore, the model was evaluated using Likert-type questions on haptic and radiological fidelity, its usefulness as a training model, as well as its imageability using CT and ultrasound.

RESULTS

The model haptically resembles OC (3.0 ± 0.5; 4-point Likert scale), can be visualized with medical imaging and macroscopically evaluated immediately after resection providing feedback. Although, participants (3.2 ± 0.4) tended to agree that they had resected the pseudotumor with an ideal safety margin (10 mm), the mean minimum resection margin was insufficient at 4.2 ± 1.2 mm (mean ± SD), comparable to reported margins in literature. Simultaneously, a maximum resection margin of 18.4 ± 6.1 mm was measured, indicating partial over-resection. Although specialists were faster at resection (p < 0.001), this had no effect on margins (p = 0.114). Overall, the model was well received by the participants, and they could see it being implemented in training (3.7 ± 0.5).

CONCLUSION

The model, which is cost-effective, cryopreservable, and provides a risk-free training environment, is ideal for training in OC biopsy and resection and could be incorporated into dental, medical, or oncologic surgery curricula. Future studies should evaluate the long-term training effects using this model and its potential impact on improving patient outcomes.

How Often is Cancer Present in Oral Cavity Re-resections After Initial Positive Margins?

OBJECTIVE

To evaluate the rate at which carcinoma is present in the re-resection specimen following initial positive margins during head and neck cancer surgery and its impact on oncologic outcomes.

STUDY DESIGN

Retrospective chart review.

METHODS

A single institution retrospective chart review of patients that underwent curative-intent surgery for oral cavity cancer was performed. Final pathology reports were reviewed to identify patients with initial positive margins who underwent re-resection during the same operation. Initial positive margin was defined as severe dysplasia, carcinoma in situ (CIS), or carcinoma. Cox proportional hazards and Kaplan-Meier analyses were used to assess for associations with survival outcomes.

RESULTS

Among 1873 total patients, 190 patients (10.1%) had initial positive margins and underwent re-resection during the same surgery. Additional carcinoma, CIS, or severe dysplasia was found in 29% of re-resections, and 31% of patients with initial positive margins had final positive margins. Half of the patients with a final positive margin had a positive margin at an anatomic site different than the initial positive margin that was re-resected. The median follow-up was 636 days (range 230-1537). Re-resection with cancer and final positive margin status was associated with worse overall survival (OS; p = 0.044 and p = 0.05, respectively). However, only age, T4 disease, and surgery for recurrent oral cavity cancer were independently associated with OS (p < 0.001, p = 0.005, and p = 0.001, respectively).

CONCLUSIONS

Fewer than a third of oral cavity re-resections contain further malignancy, which may suggest that surgeons have difficulty relocating the site of initial positive margin. Final positive margins are often at anatomic sites different than the initial positive margin.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:717-724, 2024.

Predictive factors and repetition numbers for intraoperative additional resection of initially involved soft tissue resection margins in oral squamous cell carcinoma: a retrospective study

BACKGROUND

Intraoperative additional resection (IAR) of initially microscopically involved soft tissue resection margins negatively impacts tumor recurrence in oral squamous cell carcinoma (OSCC). Increasing the selected initial macroscopic resection margin distance beyond the tumor tissue may help prevent IAR; however, the existence of predictive factors for IAR and IAR repetition numbers remains unclear. This study aimed to identify predictive factors for IAR and to evaluate the IAR repetition numbers in soft tissue for surgically treated OSCC.

METHODS

A cohort of 197 patients surgically treated for OSCC between 2008 and 2019 was retrospectively reviewed (44 patients with IAR and 153 patients without IAR). Clinical parameters (tumor location, midline involvement, clinical T-status, time between staging imaging and surgery, bone resection, monopolar use, and reconstruction flap size) and histopathological parameters (pathologic T-status [pT-status], grading, vascular invasion, and lymphatic invasion) of the two groups were compared.

RESULTS

Patients with and without IAR differed in their histopathological parameters, such as pT-status above 2 (47.7% vs. 28.1%, p = 0.014) and lymphatic invasion (13.6% vs. 4.6%, p = 0.033); however, their clinical parameters were similar (all p > 0.05). Only pT-status above 2 was predictive for IAR in a multivariable regression analysis (odds ratio 2.062 [confidence interval 1.008-4.221], p = 0.048). The IAR repetition numbers varied from zero to two (zero = 84.4%, one = 11.4%, and two = 2.3%).

CONCLUSIONS

Only postoperative available pT-status was identified as a predictive factor for IAR, underscoring the importance of improving preoperative or intraoperative tumor visualization in OSCC before selecting the initial macroscopic resection margin distance to avoid IAR.

Pre-resection Intraoperative Core Biopsies in Oral Tongue Cancer-A Pilot Study

OBJECTIVE

To assess a novel intraoperative core biopsy technique to provide enhanced guidance in partial glossectomies.

METHODS

All patients diagnosed with squamous cell carcinoma of the oral tongue were eligible for study participation. Following anesthesia, the planned resection and three points midway between the gross tumor and the intended ablation were marked. A core biopsy was performed with a needle spring on each point and sent for frozen sections. The initially planned resection was executed if the cores returned free of tumor. In case of a positive core biopsy, a new 1-1.5 cm margin was marked around that point. The main outcome measure was the closest final margin diameter, especially the deep ones. Other outcome measures were the core biopsies' sensitivity, specificity, and negative predictive value. Complications were recorded.

RESULTS

The final margins of 10 patients undergoing intraoperative core biopsies and 20 matched controls were analyzed. One patient had two positive cores and final negative margins after modifying the resection accordingly. Another patient had a positive biopsy diagnosed only on final pathology, and one close final margin. Patients that were operated with the new technique had larger margins compared to the controls: median (interquartile range) closest margin 5.95 (3.97; 9.63) mm versus 4 (2.25; 5) mm (p = 0.074) and median deep margin 8.6 (6.16; 10) mm versus 5 (3;10) mm (p = 0.411), respectively. There were no complications.

CONCLUSION

A novel pre-resection intraoperative biopsy technique is presented. Core biopsies taken during glossectomies have the potential to prevent inadequate margins.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:2232-2236, 2023.

Margins in Stage I and II Oral Cavity Squamous Cell Carcinoma: A Review From the American Head and Neck Society

Importance

The assessment and management of surgical margins in stage I and II oral cavity squamous cell carcinoma is one of the most important perioperative aspects of oncologic care, with profound implications for patient outcomes and adjuvant therapy. Understanding and critically reviewing the existing data surrounding margins in this context is necessary to rigorously care for this challenging group of patients and minimize patient morbidity and mortality.

Observations

This review discusses the data related to the definitions related to surgical margins, methods for assessment, specimen vs tumor bed margin evaluation, and re-resection of positive margins. The observations presented emphasize notable controversy within the field about margin assessment, with early data coalescing around several key aspects of management, although studies are limited by their design.

Conclusions and Relevance

Stage I and II oral cavity cancer requires surgical resection with negative margins to obtain optimal oncologic outcomes, but controversy persists over margin assessment. Future studies with improved, well-controlled study designs are required to more definitively guide margin assessment and management.

Image-Guided Intraoperative Assessment of Surgical Margins in Oral Cavity Squamous Cell Cancer: A Diagnostic Test Accuracy Review

(1) Background: The assessment of resection margins during surgery of oral cavity squamous cell cancer (OCSCC) dramatically impacts the prognosis of the patient as well as the need for adjuvant treatment in the future. Currently there is an unmet need to improve OCSCC surgical margins which appear to be involved in around 45% cases. Intraoperative imaging techniques, magnetic resonance imaging (MRI) and intraoral ultrasound (ioUS), have emerged as promising tools in guiding surgical resection, although the number of studies available on this subject is still low. The aim of this diagnostic test accuracy (DTA) review is to investigate the accuracy of intraoperative imaging in the assessment of OCSCC margins. (2) Methods: By using the Cochrane-supported platform Review Manager version 5.4, a systematic search was performed on the online databases MEDLINE-EMBASE-CENTRAL using the keywords "oral cavity cancer, squamous cell carcinoma, tongue cancer, surgical margins, magnetic resonance imaging, intraoperative, intra-oral ultrasound". (3) Results: Ten papers were identified for full-text analysis. The negative predictive value (cutoff < 5 mm) for ioUS ranged from 0.55 to 0.91, that of MRI ranged from 0.5 to 0.91; accuracy analysis performed on four selected studies showed a sensitivity ranging from 0.07 to 0.75 and specificity ranging from 0.81 to 1. Image guidance allowed for a mean improvement in free margin resection of 35%. (4) Conclusions: IoUS shows comparable accuracy to that of ex vivo MRI for the assessment of close and involved surgical margins, and should be preferred as the more affordable and reproducible technique. Both techniques showed higher diagnostic yield if applied to early OCSCC (T1-T2 stages), and when histology is favorable.

Delayed Reconstruction after Major Head and Neck Cancer Resection: An Interdisciplinary Feasibility Study

A single immediate reconstruction with free tissue transfer is the method of choice after major head and neck cancer (HNC) resection, but this is frequently associated with long operating hours. Considering regulatory working hour constraints, we investigated whether a two-staged reconstructive approach with temporary defect coverage by an artificial tissue substitute would be feasible. HNC patients underwent either immediate or delayed reconstruction after tumor resection. Patients with delayed reconstruction received preliminary reconstruction with an artificial tissue substitute followed by definitive microvascular reconstruction in a separate, second procedure. Of the 33 HNC patients, 13 received delayed reconstruction and 20 received immediate reconstruction. Total anesthesia time (714 vs. 1011 min; p < 0.002) and the total duration of hospital stay (34 ± 13 vs. 25 ± 6 days; p = 0.03) were longer in the delayed reconstruction group. Perioperative morbidity (p = 0.58), functional outcome (p > 0.1) and 5-year postoperative survival rank (p = 0.28) were comparable in both groups. Delayed reconstruction after HNC resection was feasible. Perioperative morbidity, functional outcome and overall survival were comparable to immediate reconstruction.

Immediate resection of positive margins improves local control in oral tongue cancer

OBJECTIVES

This study investigates the impact of immediate resection of positive margins on local control of oral tongue cancer.

MATERIALS AND METHODS

We analyzed 273 consecutive oral tongue cancers resected from 2013 to 2018. Additional resection was performed in cases during the initial operation based on surgeon inspection of the specimen and/or frozen margins. Positive margins were defined as invasive carcinoma/high-grade dysplasia < 1 mm from the inked edge. Patients were grouped as follows: negative margin (Group 1); positive margin with immediate additional tissue resection (Group 2); and positive margin without additional tissue resection (Group 3).

RESULTS

Overall, the rate of local recurrence was 7.7 % (21/273), and the rate of positive main specimen margin was 17.9 %. Of these patients, 38.8 % (19/49) underwent immediate additional resection of the presumed positive margin. Group 3 had higher local recurrence rates than Group 1 after adjustment for T-stage (aHR 2.8 [95 % CI 1.0-7.7], p = 0.04). Group 2 had similar rates of local recurrence (aHR 0.45 [95 % CI 0.06-3.6], p = 0.45). Three year local recurrence free survival for Groups 1, 2, and 3 were 91 %, 92 % and 73 %, respectively. Compared to the main specimen margin, sensitivity of intraoperative frozen tumor bed margins was 17.4 %, and specificity was 95 %.

CONCLUSION

In patients with positive main specimen margins, anticipation and detection in real-time with immediate additional tissue resection reduced local recurrence to rates similar to those with negative main specimen margins. These findings support the use of technology to provide real-time intraoperative margin data and guide additional resection for improved local control.

A closer look at the resection margins of buccal mucosa cancer: Their influence on local recurrence free survival

BACKGROUND

The adequate surgical margin for local control of buccal mucosa squamous cell carcinoma (BMSCC) is under debate. This study investigates surgical margins and other factors associated with local recurrence free survival (LRFS) in a large cohort of BMSCC patients.

METHODS

Multiple factors were evaluated retrospectively in 97 patients with BMSCC. Cox-regression and Kaplan-Meier curves were used for analysis.

RESULTS

The local recurrence rate was 23%. The tumor-free margin was <5.0 mm in 89% of the patients and the deep margin was significantly more often inadequate. Multivariate analysis associated pT3-classification, former smokers, tumor-free margin status, and postoperative (chemo)radiation (PO(ch)RT) with local recurrence. Re-resections did not improve LRFS in patients with <5.0 mm tumor-free margins.

CONCLUSIONS

Adequate tumor-free margins are pivotal for LRFS of BMSCC. PO(ch)RT, not re-resection, can improve LRFS in patients with <5.0 mm tumor-free margins.

Quantitative tumor depth determination using dual wavelength excitation fluorescence

Quantifying solid tumor margins with fluorescence-guided surgery approaches is a challenge, particularly when using near infrared (NIR) wavelengths due to increased penetration depths. An NIR dual wavelength excitation fluorescence (DWEF) approach was developed that capitalizes on the wavelength-dependent attenuation of light in tissue to determine fluorophore depth. A portable dual wavelength excitation fluorescence imaging system was built and tested in parallel with an NIR tumor-targeting fluorophore in tissue mimicking phantoms, chicken tissue, and in vivo mouse models of breast cancer. The system showed high accuracy in all experiments. The low cost and simplicity of this approach make it ideal for clinical use.

The Applications and Potential Developments of Ultrasound in Oral Cancer Management

Oral cancer is endemic and causes a great burden in Southern Asia. It is preferably treated by surgery with/without adjuvant radiotherapy (RT) or chemoradiation therapy, depending on the stage of the disease. Close or positive resection margin and cervical lymph node (LN) metastasis are important prognostic factors that have been presented to be related to undesirable locoregional recurrence and poor survival. Ultrasound (US) is a simple, noninvasive, time-saving, and inexpensive diagnostic modality. It can depict soft tissues very clearly without the risk of radiation exposure. Additionally, it is real-time and continuous image is demonstrated during the exam. Furthermore, the clinician can perform US-guided fine needle aspiration (FNA) or core needle biopsy (CNB) at the same time. US with/without US-guided FNA/CNB is reported to be of value in determining tumor thickness (TT), depth of invasion (DOI), and cervical LN metastasis, and in aiding the staging of oral cancer. DOI has a relevant prognostic value as reported in the eighth edition of the American Joint Committee on Cancer staging of oral cancer. In the present review, we describe the clinical applications of US in oral cancer management in different phases and potential applications in the future. In the pretreatment and surgical phase, US can be used to evaluate TT/DOI and surgical margins of oral cancer in vivo and ex vivo. The prediction of a malignant cervical LN (nodal metastasis) by the US-based prediction model can guide the necessity of FNA/CNB and elective neck dissection in clinical early-stage oral cancer. In the posttreatment surveillance phase, US with/without US-guided FNA or CNB is helpful in the detection of nodal persistence or LN recurrence, and can assess the possibility and extent of carotid artery stenosis after irradiation therapy. Both US elastography and US swallowing assessment are potentially helpful to the management of oral cancer.

Use of Intraoperative Frozen Section to Assess Final Tumor Margin Status in Patients Undergoing Surgery for Oral Cavity Squamous Cell Carcinoma

Importance

Methods of assessing final margin status in patients undergoing surgery for oral cavity squamous cell carcinoma, such as intraoperative frozen section histopathology (IFSH) taken from the tumor bed, may have limitations in accuracy.

Objective

To evaluate the accuracy and implications of using IFSH samples to assess tumor bed margins in patients undergoing surgery for oral cavity squamous cell carcinoma (SCC).

Design, Setting, and Participants

This cross-sectional study included 1257 patients who underwent surgery for oral cavity SCC between January 1, 2000, and December 31, 2015, at an academic cancer center. A total of 4821 IFSH samples were examined from 1104 patients (87.8%) who had at least 1 IFSH sample. Institutional practice is to harvest margins for IFSH from the tumor bed. Statistical analysis was performed from August 1, 2021, to April 4, 2022.

Main Outcomes and Measures

Sensitivity and specificity were calculated for IFSH samples of margins compared with the permanent pathology samples of the same tissue and for IFSH compared with the final tumor specimen histopathology (FTSH). Results were classified using a binary method, with histopathologic reports interpreted as either negative (including negative or atypia or dysplasia) or positive (including carcinoma in situ, suspicious, or positive).

Results

A total of 1257 patients met the inclusion criteria, including 709 men (56.4%), with a median age of 62 years (IQR, 52-73 years); 1104 patients (627 men [56.8%]; median age, 62 years [IQR, 52-72 years]) had IFHS samples. For IFSH relative to permanent sections of the IFSH tissue, sensitivity and specificity of IFSH were high (sensitivity, 76.5% [95% CI, 67.5%-85.5%]; specificity, 99.9% [95% CI, 99.8%-100%]), with discordant results in 24 of 4821 total specimens (0.5%). Final specimen margins were positive in 11.7% of patients (147 of 1257). Compared with FTSH, the sensitivity of IFSH for defining margin status was 10.8% (95% CI, 5.8%-15.8%), and the specificity was 99.1% (95% CI, 98.8%-99.4%). The rate of discordance was 4.0% (171 of 4284 specimens) between IFSH and FTSH.

Conclusions and Relevance

The findings of this cross-sectional study suggest that IFSH is accurate compared with permanent pathologic characteristics of the same tissue, but less reliable at assessing final margin status on the tumor specimen. Despite a high specificity, the sensitivity of IFSH compared with FTSH is low, which may be associated with the inherent inability of tumor bed IFSH margin analysis to accurately account for the 3-dimensional association of tumor margins with the periphery of the specimen and the overall low rate of positive final tumor margins. Although tumor bed IFSH is widely used in the management of oral cavity cancer, this study suggests that there are limitations of this modality in assessing the final surgical margin status.

Image-guided surgery in oral cancer: toward improved margin control

PURPOSE OF REVIEW

The aim of this review is to discuss recent studies on the assessment of tumor extension and resection margins by different intraoperative techniques allowing for image-guided surgery of oral cancer.

RECENT FINDINGS

There are different in-vivo and ex-vivo intraoperative techniques to improve margin control of which intraoperative ultrasound and targeted fluorescence-guided resections have high potential clinical value and are closest to clinical implementation.

SUMMARY

In oral cancer surgery, resection margins, particularly deep margins, are often inadequate. Intraoperative frozen section does not improve resection margin control sufficiently. Specimen-driven intraoperative assessment for gross analysis of suspected margins reduces the amount of positive resection margins substantially but leaves still room for improvement. Mucosal staining methods, optical coherence tomography and narrow band imaging can only be used for superficial (mucosal) resection margin control. Spectroscopy is under investigation, but clinical data are scarce. Intraoperative ex-vivo imaging of the resection specimen by magnetic resonance and PET/computed tomography may be used to assess resection margins but needs more research. Intraoperative in-vivo ad ex-vivo ultrasound and targeted fluorescence imaging have high potential clinical value to guide oral cancer resections and are closest to clinical implementation for improved margin control.

Impact of secondary tumor-free resection margins in soft tissue on local, regional, and distant recurrence in R0-resected oral squamous cell carcinoma

BACKGROUND

The impact of additional soft tissue resection on recurrence of oral squamous cell carcinoma (OSCC) remains controversial. The study aim was to compare recurrence between patients with secondary tumor-free resection margins after intraoperative additional resection (STF-RM) and patients with primary tumor-free resection margins without additional resection (PTF-RM).

METHODS

Forty-five patients with STF-RM were matched with patients with PTF-RM according to Union for International Cancer Control stage, tumor location, and treatment modality and compared for local, regional, and distant recurrence.

RESULTS

Patients with STF-RM showed lower local and distant control rates compared to patients with PTF-RM (66.2% vs. 82.8%; p = 0.045 and 86.3% vs. 100.0%; p = 0.021). STF-RM was the only predictor of local recurrence accounting for tumor (T) status, nodal (N) status, tumor grade, margin distance, and extracapsular extension (hazard ratio 4.21 [95% confidence interval 1.26-14.04]; p = 0.019).

CONCLUSIONS

STF-RM have an adverse impact on local and distant recurrence of OSCC.

Review:Surgical Tumour Margins and their Significance in Oral Squamous Cell Carcinoma

There are many prognostic indicators used to predict tumour recurrence and overall prognosis in oral squamous cell carcinoma (OSCC). Most of these biological factors cannot be directly influenced by clinicians managing these heterogeneous group of tumours. Excision margins can potentially be increased at the time of surgery by including more normal tissue than the commonly accepted 1cm resection distance from the macroscopic tumour edge. However, this can lead to poorer quality of life for patients and does not necessarily address microscopic extensions or dicohesive patterns of tumour growth. Surgical margins can be affected by tissue shrinkage immediately following resection, and the choice of instrument used for surgery. Currently most regard a clear resection margin as being >5mm, a close margin as more than 1mm but less than 5mm, and an involved margin less than 1mm. In this article we provide a brief overview of tumour margins in OSCC, including several recently published large meta-analyses. Based upon these and other studies, there is still conflicting data in the literature about the ideal margin for OSCC. There is a growing body of evidence which suggests a clearance of 1mm might be adequate for some cancers. However, adequacy of resection should be considered along with the many other prognostic indicators of OSCC when the multi-disciplinary team considers further treatment for these patients.

Adjuvant brachytherapy for oral squamous cell carcinomas: a single-center experience comparing low-dose and pulsed-dose-rate techniques

OBJECTIVE

This study aims to assess the outcomes of adjuvant interstitial brachytherapy (BT) to the tumor bed for oral cavity squamous cell carcinoma (SCC), and to compare the oncological outcomes and toxicity profile of low-dose-rate (LDR) and pulsed-dose-rate (PDR) BT.

DESIGN

This retrospective single-center study included all patients who underwent postoperative LDR- or PDR-BT to the tumor bed as the sole adjuvant treatment for an oral tongue or floor of the mouth SCC between January 2000 and December 2020.

RESULTS

A total of 79 patients were eligible for this study. The cohort was divided into an LDR group (n = 38) and a PDR group (n = 41). The median time interval between surgery and brachytherapy was 55 days. Median delivered total dose was 55 Gy and median hospital stay was 5 days. Five patients (8.3%) experienced grade 3-4 early toxicity, 2 in the LDR group and 3 in the PDR group. Late toxicities were present in 28 patients (44.4%) and were dominated by grade 1-2 residual pain and dysesthesia, without a statistical difference between the groups. After a median follow-up of 65.1 months, 5‑year local control (LC), disease-free survival (DFS), and overall survival (OS) for the whole cohort were 76.3% (95% CI = 63.4-85.1), 61.6% (95% CI = 49.0-72.0), and 71.4% (95% CI = 58.6-80.8), respectively.

CONCLUSION

Adjuvant BT after excision of oral cavity SCC provides satisfactory oncological outcomes along with good tolerance. In our study, PDR-BT showed similar oncological and functional results to LDR-BT in this indication.

The Impact of Histopathological Features on the Prognosis of Oral Squamous Cell Carcinoma: A Comprehensive Review and Meta-Analysis

OBJECTIVE

Over many decades, studies on histopathological features have not only presented high-level evidence of contribution for treatment directions and prognosis of oral squamous cell carcinoma (OSCC) but also provided inconsistencies, making clinical application difficult. The 8th TNM staging system of OSCC has acknowledged the importance of some histopathological features, by incorporating depth of invasion (DOI) to T category and extranodal extension (ENE) to N category. The aim of this systematic review with meta-analysis is to determine the most clinically relevant histopathological features for risk assessment and treatment planning of OSCC and to elucidate gaps in the literature.

METHODS

A systematic review was conducted using PRISMA guidelines, and the eligibility criteria were based on population, exposure, comparison, outcome, and study type (PECOS). PubMed, Cochrane, Scopus, and Web of Science were searched for articles exploring the impact of histopathological features on OSCC outcomes with Cox multivariate analysis. Pooled data were subjected to an inverse variance method with random effects or fixed effect model, and the risk of bias was evaluated using quality in prognosis studies (QUIPS). Quality of evidence was assessed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

RESULTS

The study included 172 articles published from 1999 to 2021. Meta-analyses confirmed the prognostic potential of DOI, ENE, perineural invasion, lymphovascular invasion, and involvement of the surgical margins and brought promising results for the association of bone invasion, tumor thickness, and pattern of invasion with increased risk for poor survival. Although with a small number of studies, the results also revealed a clinical significance of tumor budding and tumor-stroma ratio on predicted survival of patients with OSCC. Most of the studies were considered with low or moderate risk of bias, and the certainty in evidence varied from very low to high.

CONCLUSION

Our results confirm the potential prognostic usefulness of many histopathological features and highlight the promising results of others; however, further studies are advised to apply consistent designs, filling in the literature gaps to the pertinence of histopathological markers for OSCC prognosis.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO), identifier CRD42020219630.

The utility of intra-oral ultrasound in improving deep margin clearance of oral tongue cancer resections

OBJECTIVES

To investigate the potential utility of intra-oral ultrasound (IOUS) in guiding deep margin clearance and measuring depth of invasion (DOI) of oral tongue carcinomas (OTC).

MATERIALS AND METHODS

Retrospective chart review of consecutive patients with T1-T3 OTC who underwent intraoperative ultrasound-guided resection and a comparator group that had undergone resection without the use of IOUS both by a single surgeon. Data was extracted from operative, pathology and radiology reports. Deep margins and DOI were reviewed by a dedicated head and neck pathologist. Correlation between histologic and ultrasound DOI was assessed using Pearson correlation.

RESULTS

A total of 23 patients were included in the study cohort with a comparator group of 21 patients in the control group. None of the patients in the study cohort had a positive (cut-through) deep margin and the mean deep margin clearance was 8.5 ± 4.9 and 6.7 ± 3.8 for the IOUS and non-IOUS groups respectively (p-value 0.18) showing a non-significant improvement in the IOUS group. As a secondary outcome, there was a strong correlation between histologic and ultrasound DOI (0.9449).

CONCLUSION

Ultrasound appears to be a potentially effective tool in guiding OTC resections. In this small series, IOUS facilitated deep margin clearance and resulted in a non-statistically significant increase in deep margin clearance. Intraoral ultrasound can accurately measure lesional DOI.

Machine-Learning Assisted Discrimination of Precancerous and Cancerous from Healthy Oral Tissue Based on Multispectral Autofluorescence Lifetime Imaging Endoscopy

Multispectral autofluorescence lifetime imaging (maFLIM) can be used to clinically image a plurality of metabolic and biochemical autofluorescence biomarkers of oral epithelial dysplasia and cancer. This study tested the hypothesis that maFLIM-derived autofluorescence biomarkers can be used in machine-learning (ML) models to discriminate dysplastic and cancerous from healthy oral tissue. Clinical widefield maFLIM endoscopy imaging of cancerous and dysplastic oral lesions was performed at two clinical centers. Endoscopic maFLIM images from 34 patients acquired at one of the clinical centers were used to optimize ML models for automated discrimination of dysplastic and cancerous from healthy oral tissue. A computer-aided detection system was developed and applied to a set of endoscopic maFLIM images from 23 patients acquired at the other clinical center, and its performance was quantified in terms of the area under the receiver operating characteristic curve (ROC-AUC). Discrimination of dysplastic and cancerous from healthy oral tissue was achieved with an ROC-AUC of 0.81. This study demonstrates the capabilities of widefield maFLIM endoscopy to clinically image autofluorescence biomarkers that can be used in ML models to discriminate dysplastic and cancerous from healthy oral tissue. Widefield maFLIM endoscopy thus holds potential for automated in situ detection of oral dysplasia and cancer.

A Transcriptomic Analysis of Head and Neck Squamous Cell Carcinomas for Prognostic Indications

Survival analysis of the Cancer Genome Atlas (TCGA) dataset is a well-known method for discovering gene expression-based prognostic biomarkers of head and neck squamous cell carcinoma (HNSCC). A cutoff point is usually used in survival analysis for patient dichotomization when using continuous gene expression values. There is some optimization software for cutoff determination. However, the software's predetermined cutoffs are usually set at the medians or quantiles of gene expression values. There are also few clinicopathological features available in pre-processed datasets. We applied an in-house workflow, including data retrieving and pre-processing, feature selection, sliding-window cutoff selection, Kaplan-Meier survival analysis, and Cox proportional hazard modeling for biomarker discovery. In our approach for the TCGA HNSCC cohort, we scanned human protein-coding genes to find optimal cutoff values. After adjustments with confounders, clinical tumor stage and surgical margin involvement were found to be independent risk factors for prognosis. According to the results tables that show hazard ratios with Bonferroni-adjusted p values under the optimal cutoff, three biomarker candidates, CAMK2N1, CALML5, and FCGBP, are significantly associated with overall survival. We validated this discovery by using the another independent HNSCC dataset (GSE65858). Thus, we suggest that transcriptomic analysis could help with biomarker discovery. Moreover, the robustness of the biomarkers we identified should be ensured through several additional tests with independent datasets.

The impact of intraoperative frozen section analysis on final resection margin status, recurrence, and patient outcome with oral squamous cell carcinoma

Background

The objective of this study was to evaluate the diagnostic value of intraoperative frozen section analysis (IFSA) of tumor bed margins in patients with oral squamous cell carcinoma (OSCC).

Methods

This retrospective study includes 194 primary OSCC cases. The impact of intraoperative information by IFSA on final margin status, local recurrence, and disease-specific survival were analyzed.

Results

IFSA revealed a 50% sensitivity and a 100% specificity, with a positive and negative predictive value of 100% and 89.1%, respectively. In 19 cases, margins were rated positive by IFSA and remained positive in eight cases (42.1%), despite immediate re-resection. This constellation led to higher recurrence and lower survival rates than in cases with consecutive R0 status (each p = 0.046). Positive margins in IFSA were associated with closer final margins (p = 0.022) and early recurrences (p = 0.050).

Conclusions

Achieving instant R0 status has a crucial impact on disease recurrence and patient survival. IFSA falls short to ensure secure definite surgical margins. Thus, improved intraoperative diagnostic information on the location and extent of OSCC could support patient treatment.

Clinical relevance

Considering that patient survival has not improved despite progress in surgical and adjuvant therapy, the process and outcome of IFSA was scrutinized as one part of the treatment concept.

Assessment of the deep resection margin during oral cancer surgery: A systematic review

The main challenge for radical resection in oral cancer surgery is to obtain adequate resection margins. Especially the deep margin, which can only be estimated based on palpation during surgery, is often reported inadequate. To increase the percentage of radical resections, there is a need for a quick, easy, minimal invasive method, which assesses the deep resection margin without interrupting or prolonging surgery. This systematic review provides an overview of technologies that are currently being studied with the aim of fulfilling this demand. A literature search was conducted through the databases Medline, Embase and the Cochrane Library. A total of 62 studies were included. The results were categorized according to the type of technique: 'Frozen Section Analysis', 'Fluorescence', 'Optical Imaging', 'Conventional imaging techniques', and 'Cytological assessment'. This systematic review gives for each technique an overview of the reported performance (accuracy, sensitivity, specificity, positive predictive value, negative predictive value, or a different outcome measure), acquisition time, and sampling depth. At the moment, the most prevailing technique remains frozen section analysis. In the search for other assessment methods to evaluate the deep resection margin, some technologies are very promising for future use when effectiveness has been shown in larger trials, e.g., fluorescence (real-time, sampling depth up to 6 mm) or optical techniques such as hyperspectral imaging (real-time, sampling depth few mm) for microscopic margin assessment and ultrasound (less than 10 min, sampling depth several cm) for assessment on a macroscopic scale.

Feasibility study of ultrasound-guided resection of tongue cancer with immediate specimen examination to improve margin control - Comparison with conventional treatment

OBJECTIVES

Squamous cell carcinoma of the tongue (SCCT) is preferably treated by surgery. Free resection margins (≥5 mm) provide local control and disease-free survival. However, close (1-5 mm) and positive margins (<1 mm) are frequently encountered. We present our first experience of in-vivo ultrasound (US) guided SCCT resections followed by ex-vivo US control on the resection specimen to obtain free margins. We compare the results with those from a hisorical cohort of 91 conventionally treated SCCT patients.

MATERIALS AND METHODS

Ten patients with SCCT were included in a consecutive US-cohort. We aimed for a 5-10 mm margin during surgery, while we visualized the resection plane on US. Ex-vivo US measurements on the resection specimen determined whether there was any need for an immediate re-resection. US measurements were then compared with histopathology. Histopathological margins were compared with a consecutive cohort of 91 patients who had undergone conventional surgery for a SCCT.

RESULTS

In the US cohort, 70% of the margins were free. In the conventional cohort, this figure was 17% (P = 0.005). US predicted minimal histopathological margin distance with a mean ± SD error of 1.9 ± 1.8 mm. The mean ± SD of the histopathological overall submucosal/deep margin distance was 7.9 ± 2.1 mm in the US cohort and 7.0 ± 2.2 mm in the conventional cohort (P = 0.188). Ex-vivo examination through use of US indicated an immediate re-resection, which prevented local adjuvant treatment.

CONCLUSION

Use of US-guided SCCT resection is feasible and improves margin control.

A prospective study of intraoperative assessment of mucosal squamous cell carcinoma margins in the head and neck

BACKGROUND

In head and neck cancers, tumor margin assessment has important prognostic and therapeutic implications. Frozen section control of margins is commonly employed intraoperatively. However, this is not without limitations. The aim of this study is to determine whether intraoperative slicing of the whole specimen is feasible and what impact this may have on tumor margin assessment and the requirement for postoperative radiotherapy.

METHODS

From September 2016 to August 2018, we recruited 22 patients as a pilot study looking at both the practicalities and the clinical relevance of whole margin tumor analysis intraoperatively. Our project is a prospective single arm study with historical controls.

RESULTS

Forty-one percent of our patients required further intraoperative resection for close or involved margins. Seven of these patients who otherwise would have required adjuvant radiotherapy due to their margin status did not, after our intervention.

CONCLUSIONS

We found that although requiring resources, this process was feasible without unduly increasing operative times and with potential patient benefit including reduced incidence of adjuvant radiotherapy.

Impact of histological Oral Tongue Cancer margins on locoregional recurrence: A multi-centre retrospective analysis

OBJECTIVES

To assess the effect of the histological margins (HM) upon locoregional failure (LRF) and overall survival (OS) for oral tongue squamous cell carcinoma (OTSCC).

MATERIALS AND METHODS

We undertook a retrospective review of 258 patients, across two institutions, treated for OTSCC between 2007 and 2016. A Cox-proportional hazards model was used to compare the relative hazard ratio of HM to the accepted standard of 5 mm margins for LRF and OS.

RESULTS

The median follow up period was 4.8 years. The 5 year OS and freedom from LRF were 69% and 75% respectively. The Cox-proportional hazards model adjusted for age, DOI and LVI showed increasing risk of mortality and LRF with decreasing HM widths of <5 mm.

CONCLUSION

HM >5 mm were associated with a risk reduction of both LRF and mortality in OTSCC. This study supports >5 mm HM being the oncologic goal of surgery.

Margin Practices in Oral Cavity Cancer Resections: Survey of American Head and Neck Society Members

OBJECTIVES/HYPOTHESIS

To investigate the definition of a clear margin and the use of frozen section (FS) among practicing head and neck surgeons in oral cancer management.

STUDY DESIGN

Cross-sectional survey.

METHODS

We designed a survey that was sent to American Head and Neck Society (AHNS) members via an email link.

RESULTS

A total of 185 (13% of 1,392) AHNS members completed our survey. Most surgeons surveyed (96.8%) use FS to supplement oral cavity squamous cell carcinoma resections. Fifty-five percent prefer a specimen-based approach. The majority of respondents believe FS is efficacious in guiding re-resection of positive margins, with 81% considering the new margin to be negative. More than half of respondents defined a distance of >5 mm on microscopic examination as a negative margin.

CONCLUSIONS

To avoid oral cancer resections that result in positive margins on final analysis, and thus the need for additional therapy, most surgeons surveyed use FS. A majority of surveyed surgeons now prefer a specimen-based approach to margin assessment. Although there is a debate on what constitutes a negative margin, most surgeons surveyed believe it to be >5 mm on microscopic examination.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:782-787, 2021.

Impact of 3 mm margin on risk of recurrence and survival in oral cancer

INTRODUCTION

While positive surgical margins in oral squamous cell carcinoma (OSCC) is generally considered an adverse prognosticator, the significance of close (≤5 mm) margins is more debatable, and has not been widely adopted as an indicator for radiotherapy.

MATERIALS AND METHODS

Retrospective study of 244 patients undergoing primary surgical resection of OSCC. The impact on local control (LC), disease-specific survival (DSS) and overall survival (OS) of margins at 1 mm intervals was studied.

RESULTS

65 patients had involved (<1 mm), 119 close (1-5 mm), and 60 clear (>5 mm) main specimen margins. Involved margins was predictive of DSS (p = 0.04), but not LC (p = 0.20) or OS (p = 0.09). Both the 2 mm and 3 mm margin cut-offs were significantly associated with LC (p = 0.02, and p = 0.01), DSS (p = 0.02, and p = 0.007), and OS (p = 0.03. and p = 0.005). In a 3-tier model, use of 3 mm for demarcation between close and clear yielded good separation between survival curves of clear (≥3 mm), and close (1-<3 mm) or involved (<1 mm). Final margins, determined after incorporation of frozen sections and extra margins taken separately, was significant for LC (p = 0.04), but not for DSS (p = 0.05) or OS (p = 0.17). On multivariate analysis, <3 mm margin, T-classification, nodal status, extranodal spread, and postoperative radiotherapy, were independent predictors of DSS and OS. For LC, only T-classification was significant.

CONCLUSION

A 3 mm main specimen margin is significantly associated with survival in OSCC and may be useful for demarcation between close and clear. Further study is required to determine any impact on survival of radiotherapy for patients with <3 mm margins as sole indicator for radiotherapy.

Assessment of tumour depth in early tongue cancer: Accuracy of MRI and intraoral ultrasound

OBJECTIVES

Complete resection of tongue cancer is necessary to achieve local control. Unfortunately, deep resection margins are frequently inadequate. To improve deep margin control, accurate knowledge of tumour thickness is pivotal. Magnetic resonance imaging (MRI) and intraoral ultrasound (ioUS) are frequently applied for tumour staging. This study explores the accuracy of these techniques to estimate depth of invasion.

MATERIALS AND METHODS

The data of patients with a T1-2 tongue cancer that had been treated surgically between 2014 and 2018 were retrospectively analysed. Measurements that had been taken by either MRI or ioUS were compared with those taken during histopathology.

RESULTS

A total of 83 patients with tongue cancer had undergone a pre-operative MRI and 107 had been studied through an ioUS. Tumour thickness measured by MRI (r = 0.72) and ioUS (r = 0.78) correlated significantly (p < 0.001) with histopathological depth of invasion (DOI). In tumours with a DOI of 0-10 mm, MRI has a mean absolute difference with histopathology of 3.1 mm (SD 3.2 mm) and ioUS of 1.6 mm (SD 1.3 mm). In tumours with a DOI greater than 10 mm, MRI has a mean absolute difference of 3.5 mm (SD 3.0 mm) and ioUS of 4.7 mm (SD 3.5 mm).

CONCLUSION

Estimation of histopathological DOI in tongue cancers with DOI till 10 mm is very accurate through use of ioUS. ioUS tends to underestimate DOI in tumors exceeding 10 mm DOI. MRI tends to overestimate DOI in both thin and thick tumours. Since ultrasound measurements can be performed during surgery, ioUS could potentially guide the surgeon in the achievement of adequate resection margins.

An Update on Surgical Margins in the Head Neck Squamous Cell Carcinoma: Assessment, Clinical Outcome, and Future Directions

PURPOSE OF REVIEW

Failure to achieve tumor-free margins is the single largest cause of death for head neck cancer patients. At the same time, it is the only factor that is in complete control of the surgeon. This review summarizes evidence for the definition, clinical implications, and methods to achieve optimal margins.

RECENT FINDINGS

The previous universally followed definition of adequate margin (5 mm in final histopathology) has been disputed. Various biological, optical, and imaging adjuncts can aid in achieving optimal margins. Extent of resection and margins in human papilloma virus (HPV)-positive oropharyngeal cancers and following induction chemotherapy remain controversial. Though practiced widely, frozen section-guided margin revision has not conclusively shown improved local control rates. The role of molecular assessment of margins is promising but not established. The definition of adequate margin differs according to the site in the head neck region. Currently, the 5-mm margin at final histopathology is the most commonly accepted definition of an "adequate" margin.

Comparison of Intraoperative Sonography and Histopathologic Evaluation of Tumor Thickness and Depth of Invasion in Oral Tongue Cancer: A Pilot Study

BACKGROUND AND PURPOSE

For primary squamous cell carcinoma of the oral tongue, accurate assessment of tumor thickness and depth of invasion is critical for staging and operative management. Currently, typical imaging modalities used for preoperative staging are CT and MR imaging. Intraoperatively, CT or MR imaging cannot provide real-time guidance, and assessment by manual palpation is limited in precision. We investigated whether intraoperative sonography is a feasible technique for assessment of tumor thickness and depth of invasion and validated its accuracy by comparing it with histopathologic evaluation of the resected specimen.

MATERIALS AND METHODS

Twenty-six patients with squamous cell carcinoma of the oral tongue who underwent tumor resection by a single surgeon between March 31, 2016, and April 26, 2019, were prospectively identified. Intraoperative sonography was obtained in planes longitudinal and transverse to the long axis of the tumor. Twenty-two patients had archived images that allowed measurements of tumor thickness and depth of invasion sonographically. Two patients had dysplasia and were excluded. The remaining 20 patients had histologic tumor thickness and histologic depth of invasion measured by a single pathologist.

RESULTS

The mean sonographic tumor thickness was 7.5  ± 3.5 mm, and the mean histologic tumor thickness was 7.0  ± 4.2 mm. Mean sonographic depth of invasion and histologic depth of invasion were 6.6  ± 3.4  and 6.4 ± 4.4 mm, respectively. There was excellent correlation between sonographic and histologic measurements for both tumor thickness and depth of invasion with Pearson correlation coefficients of 0.95 (95% CI, 0.87-0.98) and 0.95 (95% CI, 0.87-0.98), respectively.

CONCLUSIONS

Intraoperative sonography can provide reliable, real-time assessment of the extent of tongue tumors.

Management of locally advanced oral cancers

Despite easy access to clinical examination majority of oral cancer patients ironically present with locally advanced disease, which is a heterogeneous group that includes all stage III/IV tumours in absence of distant metastasis. The AJCC TNM classification has included all tumours with depth of invasion >1 cm into locally advanced group irrespective of their surface dimensions. Surgery followed by adjuvant therapy provides best results and should be offered to all patients when operable. There have been a slew of recent publications popularising the concept of compartmental excision in variance to traditional resection with adequate margins. The role of chemotherapy has been explored in this group of patients for both organ preservation as well as to aid bioselection of suitable patients with borderline operable tumours for surgery.

Intraoperative Margin Assessment in Head and Neck Cancer: A Case of Misuse and Abuse?

Surgical removal with negative margins is the preferred management of oral squamous cell carcinomas. This review summarizes statements by professional organizations and data supporting the specimen-driven approach to margin assessment. Practical aspects of the intraoperative margin assessment, as guided by gross examination, are presented. The most cost- and time-efficient method of intraoperative margin assessment depends on desired margin clearance and likelihood of other adverse histologic factors, such as extranodal extension, perineural invasion, which are likelier in advanced carcinomas. Intraoperative surgeon-pathologist communication can be improved by reporting to surgical team gross distances to all or selected closest margins, before choosing margins for microscopic frozen examination. Case specific mitigation strategies to minimize the negative impact of tumor-bed driven margin assessment or of suboptimal margin revision are proposed. Based on size, shape, histology, size of carcinoma at the margin, and orientation of the additional tissue, margin revision may be judged as adequate (conversion of a positive margin into a negative one), inadequate (positive margin remains positive), or indeterminate. The significance of anatomic subsite based labeling, radial margin sampling from the main resection specimen, and the relationship between the distance to closest margin and local control are highlighted. The modern definition of safe margin would account for other parameters, such as perineural invasion. An updated approach to resolution of frozen versus permanent sampling issues is outlined. Future studies are needed to design and validate risk models that would help to determine for individual patient what represents a safe margin and how to judge the quality of margin revision.