Invasion of the mandible in gingivobuccal complex cancers: Histopathological analysis of routes of tumour entry and correlation with preoperative assessment

Compartmentalization of High Infratemporal Fossa in Oral Cavity Squamous Cell Carcinomas and Its Impact on Clinical Outcome

BACKGROUND

According to the 8th edition of the American Joint Committee on Cancer (AJCC), involvement of the masticator space and infratemporal fossa (ITF) in oral cancers indicates advanced disease (T4b), which is often considered unresectable. Previous studies have shown that the extent of ITF involvement influences management and outcomes. Therefore, to optimize management, T4b disease should be subclassified based on ITF involvement. Notably, infranotch disease has a more favorable prognosis compared to supranotch disease. Our study also observed that certain subsets of high anterior retroantral ITF involvement may be operable with favorable clinical outcomes. This study aims to derive a new image-based compartmentalization of high ITF involvement and assess its impact on the management and outcomes of oral head and neck squamous cell carcinoma (HNSCC) patients with high ITF involvement.

MATERIALS AND METHODS

This retrospective observational study included 154 non-metastatic, upfront unresectable locally advanced HNSCC patients who were fit for induction neoadjuvant chemotherapy (NACT). ITF involvement was classified into distinct compartments, and detailed staging of the primary tumor (T) and regional nodes (Ns) was performed. Clinical data, including patient demographics, treatment received, and follow-up notes, were documented. Prognosis was assessed using survival metrics: event-free survival (EFS), progression-free survival (PFS), and overall survival (OS). The ITF was categorized into the following compartments: compartment 1 (low ITF: medial pterygoid), compartment 2 (anterior high ITF: retroantral fat), compartment 3 (posterior high ITF), including 3a (paramandibular compartment: paramandibular fat/temporalis), 3b (muscle compartment: lateral pterygoid), and 3c (Perineural compartment: pterygopalatine fossa and pterygomaxillary fissure).

RESULTS

Of the 154 cases, 142 (92%) were classified as T4b, with 63 (40.9%) having high ITF involvement and 79 (55.6%) having low ITF involvement. Twelve cases had T4a disease, which was deemed unresectable due to extensive nodal involvement. Subcompartmentalization of the 63 high ITF cases revealed 26 (41.2%) with compartment 2 involvement, 17 (26.9%) with compartment 3a involvement, 11 (17.4%) with compartment 3b involvement, and 9 (14%) with compartment 3c involvement. Disease progression following NACT was significantly higher in compartment 3c, which showed a poor response (p = 0.007). Univariate analysis for PFS revealed similar outcomes for compartments 1 and 2 (p = 0.692), while compartment 3 demonstrated poorer outcomes (p = 0.033). Among thosehigh ITF involvement, compartment 3c had the worst PFS outcome (p = 0.03).

CONCLUSIONS

Baseline imaging plays a critical role in guiding individualized treatment and predicting clinical outcomes. Low ITF involvement and disease limited to the high retroantral fat compartment exhibit similar clinical outcomes. Among the posterior high ITF compartments, involvement of the pterygopalatine fossa and pterygomaxillary fissure (compartment 3c) is associated with the worst prognosis and poor response to chemotherapy. Subcompartmentalization of ITF involvement provides valuable prognostic information to tailor treatment strategies.

The Role of Chest Physiotherapy in Enhancing Quality of Life in a Postoperative Patient With Gingivobuccal Sulcus Carcinoma and Empyema: A Case Report

Gingivobuccal cancer encompasses a group of malignancies that affect the alveolus, retromolar trigone, buccal mucosa, and gingivobuccal sulcus (GBS). Among these, GBS carcinoma is the most prevalent malignant tumor found in the oral cavity. We present the case of a 56-year-old male who experienced pain in his right cheek for two months and was subsequently diagnosed with GBS cancer in the right buccal region, leading to surgical intervention. After one month, the patient was referred to chest physiotherapy due to complaints of cough with secretion and breathlessness. The chest physiotherapy protocol included deep breathing exercises, segmental breathing, and the Active Cycle of Breathing Technique, among others. Outcome measures used to assess progress included the Modified Medical Research Council Scale, Numeric Pain Rating Scale, 6-Minute Walk Test, and Short Form 36. The accompanying physiotherapy protocol demonstrated a positive effect on improving the patient's quality of life, functional capacity, and exercise performance.

Current Concepts of Ablative Surgery in Oral Cavity Cancer

Introduction

Ablative surgery has evolved over the years with the attempt to extirpate the tumor in its entirety with the understanding of the molecular tumor biology, pattern of tumor invasion of the tumors, as well as availability of better instrumentations.

Materials and Methods

Subset-based evaluation and management of oral cancer.

conclusion

For oral cancer, surgery is still the primary therapeutic option. To establish surgical adequacy, a wide excision with sufficient margins in all three dimensions must be carried out.

Invasion of the bucco-mandibular space by oral squamous cell carcinoma: histopathological analysis of invasion pattern

Background

This study aimed to determine the patterns of invasion of oral squamous cell carcinoma (OSCC) into the bucco-mandibular space (BMS) using detailed histopathological analysis and to assess clinical outcomes.

Methods

Patients with OSCC who underwent segmental mandibulectomy or hemi-mandibulectomy combined with resection of the BMS between 2012 and 2021 were included. The invasions of the BMS were classified into three patterns. Pattern A was defined as a horizontal invasion, Pattern B as a vertical invasion, and Pattern C as an expansive invasion.

Results

In total, 109 patients were reviewed. Of these 109 patients, the primary tumor affected the lower gingiva in 78 patients, the buccal mucosa in 18 patients, and was a primary intraosseous carcinoma of the mandible in 13 patients. Invasion of the BMS was significantly associated with a higher pathological T stage, positive/close margins, and lower disease-free survival (DFS) rates. The DFS rates were 86.7% and 66.0% in the BMS non-invasion and invasion groups, respectively. The DFS rates for each type of invasion were 82.1% for Pattern A, 67.4% for Pattern B, and 48.0% for Pattern C (P=0.277).

Conclusion

Patients with BMS invasion have a poorer prognosis than those without invasion of the BMS. Therefore, adjuvant therapy is necessary, especially in Patterns B and C. Evaluation of preoperative BMS invasion patterns is important for predicting the prognosis of OSCC.

Accuracy of preoperative clinical examination and imaging for mandibular resection in oral cancer: a systematic review of diagnostic test accuracy studies

The aim of this systematic review is not only to analyse the accuracy of clinical examination and radiological preoperative assessment of mandibular invasion reported in isolation, but to highlight those reports that have combined them. A total of 1636 titles and abstracts published between 1995 - 2000 were screened following a literature search in PubMed. Keywords were "mandible" and "squamous cell carcinoma". A total of 90 full manuscripts were reviewed with 24 meeting defined inclusion/exclusion criteria and yielding the data reported. The most sensitive test was single photon emission tomography with eight out of the 10 studies reporting sensitivity higher than 95%. Magnetic resonance imaging (MRI) demonstrated superior sensitivity but was less specific than computed tomography (CT). A single report attempted to report the combined CT and MRI scans with a separate expert reporting but did not result in more reliable detection. Periosteal stripping was not reported, and there was insufficient data to establish the value of new technologies. This review confirms that, to our knowledge, there are no reliable data on the results of combining imaging techniques with or without clinical examination. It emphasises the lack of data for the combination of preoperative techniques to enhance safe oncological resection of the mandible. Based on the evidence gathered in this review an algorithm of assessment of possible mandibular invasion is proposed. With new technologies available and 3-dimensional models to help plan the mandibular resection and reconstruction, the potential of combining preoperative investigations should be fully realised through prospective research.

Determination of diagnostic and predictive parameters for vertical mandibular invasion in patients with lower gingival squamous cell carcinoma: A retrospective study

Vertical mandibular invasion of lower gingival squamous cell carcinoma (LGSCC) determines the method of resection, which significantly affects the patient's quality of life. Therefore, in mandibular invasion by LGSCC, it is extremely important to monitor progression, specifically whether invasion is limited to the cortical bone or has progressed to the bone marrow. This retrospective study aimed to identify the diagnostic and predictive parameters for mandibular invasion, particularly vertical invasion, to enable appropriate selection of the method of mandibular resection. Of the patients who underwent surgery for LGSCC between 2009 and 2017, 64 were eligible for participation in the study based on tissue microarrays (TMA) from surgical specimens. This study analyzed morphological features using computed tomography (CT), and metabolic characteristics using maximum standardized uptake value (SUVmax), peak value of SUV (SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Moreover, immunohistochemical analysis of proteins, including parathyroid hormone-related protein (PTHrP), interleukin-6 (IL-6), E-cadherin, and programmed cell death-1 ligand 1 (PD-L1), was performed. Statistical analysis was performed using univariate logistic regression analysis with the forward selection method. The present study showed that MTV (≥2.9 cm3) was an independent diagnostic and predictive factor for positivity of mandibular invasion. Additionally, TLG (≥53.9 bw/cm3) was an independent diagnostic and predictive factor for progression to bone marrow invasion. This study demonstrated that in addition to morphological imaging by CT, the volume-based parameters of MTV and TLG on fluorine-18 fluorodeoxyglucose positron emission tomography were important for predicting pathological mandibular invasion in patients with LGSCC. A more accurate preoperative diagnosis of vertical mandibular invasion would enable the selection of appropriate surgical procedure for mandibular resection.

Prognostic Impact of Pattern of Mandibular Involvement in Gingivo-Buccal Complex Squamous Cell Carcinomas: Marrow and Mandibular Canal Staging System

Purpose

To study the pattern of mandibular involvement and its impact on oncologic outcomes in patients with gingivo-buccal complex squamous cell carcinoma (GBC-SCC) and propose a staging system based on the pattern of bone involvement (MMC: Marrow and mandibular canal staging system) and compare its performance with the 8th edition of the American Joint Committee on Cancer (AJCC8).

Methods

This retrospective observational study included treatment-naïve GBC-SCC patients who underwent preoperative computed tomography (CT) imaging between January 1, 2012, and March 31, 2016, at a tertiary care cancer center. Patients with T4b disease with high infratemporal fossa involvement, maxillary erosion, and follow-up of less than a year were excluded. The chi-square or Fisher’s exact test was used for descriptive analysis. Kaplan–Meier estimate and log-rank test were performed for survival analysis. Multivariate analysis was done using Cox regression analysis after making adjustments for other prognostic factors. p-Value <0.05 was considered as significant. Based upon the survival analysis with different patterns of bone invasion, a new staging system was proposed “MMC: Marrow and mandibular canal staging system”. “Akaike information criterion” (AIC) was used to study the relative fitted model of the various staging (TNM staging—AJCC8) with respect to survival parameters.

Results

A total of 1,200 patients were screened; 303 patients were included in the study. On radiology review, mandibular bone was involved in 62% of patients. The pattern of bone involvement was as follows: deep cortical bone erosion (DCBE) in 23%, marrow in 34%, and marrow with the mandibular canal in 43% of patients. Patients with DCBE and no bone involvement (including superficial cortical) had similar survival [disease-free survival (DFS) and locoregional recurrence-free survival (LRRFS)], and this was significantly better than those with marrow with or without mandibular canal involvement (for both DFS and LRRFS). Patients with DCBE were staged using the MMC, and when compared with the AJCC8, the MMC system was better for the prediction of survival outcomes, as AIC values were lower compared with those of the AJCC8. There was a significant association (p = 0.013) between the type of bone involvement and the pattern of recurrence.

Conclusions

For GBC-SCC, only marrow with or without mandibular canal involvement is associated with poorer survival outcomes. As compared with the AJCC8, the proposed Mahajan et al. MMC staging system downstages DCBE correlates better with survival outcomes.

Prospective Phase II Open-Label Randomized Controlled Trial to Compare Mandibular Preservation in Upfront Surgery With Neoadjuvant Chemotherapy Followed by Surgery in Operable Oral Cavity Cancer

PURPOSE

The objective of this study was to explore the potential role and safety of neoadjuvant chemotherapy (NACT) in tumor shrinkage and resultant mandibular preservation in oral cancers compared with conventional surgical treatment.

METHODS

This study was a single-center, randomized, phase II trial of treatment-naive histologically confirmed squamous cell carcinoma of the oral cavity with cT2-T4 and N0/N+, M0 (American Joint Committee on Cancer, seventh edition) stage, necessitating resection of the mandible for paramandibular disease in the absence of clinicoradiologic evidence of bone erosion. The patients were randomly assigned (1:1) to either upfront surgery (segmental resection) followed by adjuvant treatment (standard arm [SA]) or two cycles of NACT (docetaxel, cisplatin, and fluorouracil) at 3-week intervals (intervention arm [IA]), followed by surgery dictated by postchemotherapy disease extent. All patients in the IA received adjuvant chemoradiotherapy, and patients in the SA were treated as per final histopathology report. The primary end point was mandible preservation rate. The secondary end points were disease-free survival and treatment-related toxicity.

RESULTS

Sixty-eight patients were enrolled over 3 years and randomly assigned to either SA (34 patients) or IA (34 patients). The median follow-up was 3.6 years (interquartile range 0.95-7.05 years). Mandibular preservation was achieved in 16 of 34 patients (47% [95% CI, 31.49 to 63.24]) in the IA. The disease-free survival (P = .715, hazard ratio 0.911 [95% CI, 0.516 to 1.607]) and overall survival (P = .747, hazard ratio 0.899 [95% CI, 0.510 to 1.587]) were similar in both the arms. Complications were similar in both arms, but chemotherapy-induced toxicity was observed in the majority of patients (grade III: 14, 41.2%; grade IV: 11, 32.4%) in the IA.

CONCLUSION

NACT plays a potential role in mandibular preservation in oral cancers with acceptable toxicities and no compromise in survival. However, this needs to be validated in a larger phase III randomized trial.

Comparison of different diagnostic imaging techniques for the detection of bone invasion in oral cancers

OBJECTIVES

To evaluate the ability of different imaging modalities to accurately detect bone invasion in oral squamous cell carcinomas.

PATIENTS AND METHODS

Patients with oral squamous cell carcinoma, who were scheduled for mandibulectomy or maxillectomy, underwent clinical evaluation using five preoperative imaging diagnosis methods-contrast-enhanced MRI, CT, ^99mTc scintigraphy (Tc scan), FDG-PET CT (PET/CT), and panoramic radiography. The sensitivity and specificity of each modality in detecting bone invasion were calculated by comparing the findings on the images with postoperative histopathological findings. In a subgroup of patients, we further assessed the ability of MRI and CT to detect the accurate extent of bone invasion, including the height, width, and depth in patients with pathological mandibular invasion.

RESULTS

Overall, 50 patients were enrolled in this study, and nine patients with pathological mandibular invasion were included in our subgroup analysis. MRI was found to be the most useful method in detecting bone invasion, showing the highest sensitivity (88.9%) and negative predictive values (92.3%). CT (87.5% specificity and 77.8% sensitivity) was more specific than MRI, though less sensitive. Combined PET/CT was more sensitive (83.3%) and less specific (71.9%) than CT. Tc scan had high sensitivity (88.9%); however, the specificity was relatively low (71.9%).

CONCLUSION

MRI was the most useful method in detecting bone invasion. A negative MRI result definitively excludes bone marrow invasion. In patients with positive MRI findings, a negative CT may be useful in ruling out bone marrow invasion.

Diagnostic efficacy of PET-CT, CT, and MRI in preoperative assessment of mandibular invasion caused by head and neck cancer: A systematic review and meta-analysis

OBJECTIVE

This study aims to conduct a systematic review and meta-analysis of the performance of PET-CT, CT, and MRI in diagnosing mandible invasion induced by head and neck cancer (HNC).

MATERIALS AND METHODS

The MEDLINE, Embase, Science Direct, CNKI and CQVIP databases were searched from inception until August 1, 2020. Then, a meta-analysis was conducted to calculate the combined diagnostic values with the corresponding 95% CIs. Two independent researchers completed the full text screening, data abstraction, and risk assessment.

RESULTS

This meta-analysis included 53 studies (N = 2 946 participants). For the pooled sensitivity (SEN), MRI (SEN: 0.88, 95% CI: 0.81-0.93) was found to have a significantly higher SEN (P = 0.0045), when compared to CT (SEN: 0.77, 95% CI: 0.71-0.82), while compared with PET-CT (SEN: 0.88, 95% CI: 0.64-0.97), the SEN was approximately equal (P > 0.05). The analysis revealed that the combined specificity (SPE) of MRI (SPE: 0.83, 95% CI: 0.74-0.89) and PET-CT (SPE: 0.81, 95% CI: 0.57-0.93) was lower than that of CT (SPE: 0.87, 95% CI: 0.83-0.90), but there was no statistical significance among these (P > 0.05). The comparison of the area under curve (AUC) reflected that PET-CT, CT and MRI have approximately equal summary diagnostic power in detecting mandibular invasion (P > 0.05).

CONCLUSION

The findings suggest that compared with CT, MRI is significantly superior for higher SEN in diagnosing mandibular invasion. The SEN of MRI and PET-CT were approximately equal. For the summary of diagnostic power, more prospective clinical trials that directly compare these three methods are needed in the future.

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.

Imaging in oral cancers: A comprehensive review

This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management of oral cavity squamous cell carcinoma (OSCC). Early OSCC can be treated with either surgery alone while advanced cancers are treated with a combination of surgery, radiotherapy and/or chemotherapy. Considering the complex anatomy of the oral cavity and its surrounding structures, imaging plays an indispensable role not only in locoregional staging but also in the distant metastatic work-up and post treatment follow-up. Knowledge of the anatomy with understanding of common routes of spread of cancer, allows the radiologist to accurately determine disease extent and augment clinical findings to plan appropriate therapy. This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management.

Mandible handling in the surgical treatment of oral squamous cell carcinoma: lessons from clinical results after marginal and segmental mandibulectomy

OBJECTIVE

The aim of this retrospective, single-center study was to analyze long-term results after marginal and segmental mandibulectomies in patients with oral squamous cell carcinoma (OSCC).

STUDY DESIGN

The study included 259 patients treated for OSCC with mandibulectomy between 1996 and 2010. Data acquisition consisted of analysis of operation reports, re-evaluation of histologic bone specimens, and collection of clinical follow-up data.

RESULTS

Of the included patients, 86.5% had received segmental and 13.5% marginal mandibulectomies. Patients who received segmental mandibulectomy generally displayed a higher TNM (tumor-node-metastasis) stage; 47% of patients who received segmental mandibulectomy and 14% of those receiving marginal mandibulectomy showed bone infiltration (pT4 a). Of all patients with bone infiltration, 49% showed an invasive histologic infiltration pattern, and 35% showed an erosive histologic infiltration pattern. We found healthy residual crestal bone height in 43% of all segmental mandibulectomies. Only 8% of all patients were prosthodontically rehabilitated. With regard to prognostic parameters, there was no significant difference between patients receiving marginal mandibulectomy and those receiving segmental mandibulectomy.

CONCLUSIONS

Because healthy residual crestal bone height was found in 43% of all patients who had received segmental mandibulectomies, it is conceivable that a significant number of patients would profit from marginal mandibulectomy, at least in cases of absent or erosive bone infiltration pattern, because the residual crestal bone is functionally stable.