Mandibular invasion in oral squamous cell carcinoma: investigation by clinical examination and orthopantomogram

Staging and Treatment Implications in Small Oral Squamous Cell Carcinoma with Bone Infiltration

Background/Objectives: Oral squamous cell carcinoma (OSCC) with bone infiltration is categorized as a T4 tumor regardless of its size. T4 tumors are an indication for postoperative radiotherapy, which could be overtreatment for small oral squamous cell carcinoma (SOSCC) with bone infiltration. Methods: A retrospective study of 189 patients with OSCC with the potential for mandibular infiltration was performed. The influence of the predictive variables on overall survival (OS) and disease-free survival (DFS) was assessed using the Kaplan-Meier method. A random forest approach was applied to determine the importance of each variable for survival in a multivariate context, and a partial correlation analysis was performed. Results: A statistical analysis of the effects of covariates suggested only a small influence of bone infiltration on OS. Patients with bone infiltration had a 5-year OS of 69%, and those without bone invasion had a 5-year OS of 71%. Age, lymph node metastasis, depth of invasion (DOI), and tumor size had the most decisive prognostic influence on survival. Conclusions: Bone infiltration appears to have less prognostic explanatory power than other known variables regarding OS. Therefore, adjuvant therapy should be carefully evaluated.

Prevalence of Radiolucent and Radiopaque Jawbone Lesions Using Panoramic Radiographic Analysis in Hail, Saudi Arabia: A Retrospective, Cross-Sectional, Observational Study

Background Oral diseases are among the most prevalent public health issues worldwide, underscoring the importance of early diagnosis and effective prevention programs. Determining the prevalence of jawbone lesions is crucial for developing targeted interventions and ensuring timely treatment. Panoramic radiography, also known as orthopantomogram, has become a cornerstone in radiographic examinations, offering a comprehensive view of the dental and maxillofacial regions. Its accessibility and ability to detect a wide range of pathologies make it an invaluable diagnostic tool. This study aimed to assess the prevalence and distribution of radiolucent and radiopaque jawbone lesions in the population of Hail, Saudi Arabia, using panoramic radiographic analysis. Methodology A retrospective, cross-sectional study was conducted using pre-existing panoramic radiographs of individuals aged 18 years and older in Hail, Saudi Arabia. The radiographs were analyzed for the presence of jawbone lesions, classified as radiolucent, radiopaque, or mixed, and their anatomical distribution was recorded. Statistical analysis was performed using the chi-square test, with a significance level set at p-values <0.05. Results A total of 389 jawbone lesions were identified in 177 subjects, representing a prevalence of 45.5%. Radiolucent lesions were the most common, observed in 153 (39.3%) subjects, while radiopaque lesions were found in 18 (4.6%) subjects, and mixed lesions in six (1.5%) subjects. The mandible was more frequently affected than the maxilla, with 104 (59%) lesions occurring in the mandible and 52 (29%) lesions in the maxilla. The posterior region of the jaw was the most commonly involved site, accounting for 124 (31.9%) cases. Gender and age did not significantly influence the prevalence or type of lesions, although a higher incidence was noted in the 31-45-year age group. Conclusions This study revealed a significant prevalence of jawbone lesions in the Hail population, with radiolucent lesions being the most common type, predominantly affecting the posterior region of the mandible. The findings highlight the importance of early detection and targeted dental health initiatives in this region. Further research, particularly longitudinal studies, is recommended to explore the natural history of these lesions and their impact on oral health over time.

A Concordance Between Clinical and Pathological Tumor Staging of Oral Squamous Cell Carcinoma: An Institutional Study

BACKGROUND

Among oral diseases, oral cancer is the primary cause of death and poses a serious health risk. Primary tumor (T) - regional lymph node (N) - distant metastasis (M) comprising (TNM) staging is crucial for planning treatment strategies for patients with oral squamous cell carcinoma (OSCC).

AIM

This study evaluated the predictive accuracy of clinical TNM staging of OSCC to histopathological staging (pTNM) in an institutional setting.

MATERIALS AND METHODS

Fifty-four consecutive histologically confirmed, surgically treated OSCC cases were evaluated for TNM staging. The study compared the clinical staging at the time of surgery with the pathological staging obtained from excisional biopsy reports. Microsoft Excel (Microsoft® Corp., Redmond, WA, USA) was used for the data compilation and descriptive analysis. The chi-square test, analysis of variance (ANOVA), and Tukey's Honest Significant Difference (HSD) posthoc test were used to compare the data for statistical significance with p value <0.05 using Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 23.0, Armonk, NY).

RESULTS

The alveolar mucosa (n=22, 40.74%) was the most frequently occurring site, followed by the tongue (n=17, 31.48%). Out of the 54 included cases, based on clinical tumor size, there were T1 (n=6), T2 (n=13), T3 (n=13), T4a (n=16) and T4b (n=6). T2 tumors were usually upstaged (n=7) while T4a (n=8) tumors were most often downstaged. T4a (n=8) had the best concordance between clinical and histopathological staging, followed by T2, T3, and T1. In nodal status, N1 showed the most variation. The chi-squared test showed statistical significance for tumor size comparison (p <0.001) and nodal status comparison (p=0.002). ANOVA test did not show any statistical significance. Tukey's HSD posthoc test showed statistical significance (p=0.034) for N0 and N1 status. The highest concordance was shown by N0 and N1 followed by N2b.

CONCLUSION

Preoperative radiological and clinical assessments are essential for deciding on a patient's course of treatment. However, not all patients may require radiographs to determine tumor size or nodal status assessment. Accurate diagnosis is vital for the treatment planning of OSCC.

Clinical, Radiological, and Pathological Correlation of Mandibular Invasion in Carcinoma Bucco-alveolar Complex

A prospective cross-sectional study was conducted to correlate clinically, radiologically, and pathologically the mandibular invasion in carcinoma bucco-alveolar complex. All biopsy-proven oral cavity cancer cases (64 patients) were assessed clinically and radiologically for involvement of the mandible. Preoperative clinicoradiological findings were compared with postoperative histopathological findings. In our study, oral cancer was 4 times more prevalent in males as compared to females and clinical evaluation was found to be highly sensitive in predicting mandibular invasion. Orthopantomogram showed sensitivity of 66.6% and specificity of 100%. CT scan showed sensitivity of 100% and specificity of 46% whereas MRI showed sensitivity of 54.5% and a specificity of 96%. MRI correlates well with final histopathology in predicting size of tumor. Prevalence of bony invasion in carcinoma oral cavity was 18%. We noted an inverse relation with tumor differentiation and mandibular invasion, and none of the verrucous carcinoma lesions showed mandibular invasion. Association of clinical T and N staging with postoperative histopathology was found to be statistically significant. Despite recent advances in molecular biology, radiological techniques, and newer modalities like visual surgical planning, exact measurement of bone invasion is still challenging. At present, CT scan and MRI along with clinical evaluation are widely used to evaluate mandibular invasion in carcinoma oral cavity, and all these are complementary to each other. The recent progress in tissue engineering technologies and stem cell biology has significantly promoted the development of regenerative reconstruction of jawbone defects.

Diagnostic accuracy of contrast-enhanced computed tomography in assessing bone invasion in patients with oral squamous cell carcinoma

OBJECTIVES

This study aimed to evaluate the diagnostic accuracy of contrast-enhanced computed tomography (CT) in detecting bone invasion in oral squamous cell carcinoma (OSCC) patients and to explore clinicopathological factors associated with its reliability.

MATERIALS AND METHODS

417 patients underwent preoperative contrast-enhanced CT followed by radical surgery. The presence or absence of bone invasion served as the outcome variable, with histopathologic examination of the resection specimen considered the gold standard. Statistical analyses, comprising correlation analyses and the determination of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were conducted.

RESULTS

CT exhibited 76.85% sensitivity, 82.20% specificity, 47.14% PPV, and 89.67% NPV. False-positive and false-negative rates were 11.27% and 5.99%, respectively. Artifacts affected assessment in 44 patients, but not in those with bone invasion. Tumor size, depth of invasion (DOI), tumor localization at the upper jaw, lymphatic invasion, and perineural invasion correlated with incorrect identification of bone invasion (Chi-square, p < 0.05).

CONCLUSIONS

Despite utilizing thin-section CT, notable false-positive and false-negative results persisted. Patients with T3 tumors, DOI ≥ 10 mm, or upper jaw tumors are at higher risk for misidentification of bone invasion. Combining multiple methods may enhance diagnostic accuracy, and the integration of artificial intelligence or tracking electrolyte disturbances by tumor depth profiling shows promise for further assessment of bone invasion before histopathology.

CLINICAL RELEVANCE

Surgeons should consider these insights when planning tumor resection. Supplementary imaging may be warranted in cases with high risk factors for misidentification. Further methodological advancements are crucial for enhancing diagnostic precision.

Squamous cell carcinoma of mandible with unusual clinical presentation: A rare case report and review of literature

Squamous cell carcinoma (SCC) is commonly seen malignant epithelial neoplasm of the oral cavity, which is characterized by variable clinical manifestations. It arises from dysplastic squamous epithelium. Majority of the spread of oral SCC (OSCC) to mandibular bone occurs by direct infiltration of the tumour through alveolar ridge or lingual cortical plate. Only 6% of the OSCC present with primary tumour; hence, a comprehensive whole body imaging needs to be done for ruling out primary tumour anywhere else in the body along with a proper clinical examination. Here, we present an unusual case of long-standing aggressive primary malignancy with unusual clinical presentation in mandibular anterior region associated with chronic tobacco chewing in a 65-year-old male patient.

Oral squamous carcinoma: Aggressive tumor pattern of invasion predicts direct mandible invasion

BACKGROUND

Aggressive histologic worst pattern of invasion (WPOI) in surrounding soft tissue has been shown to be predictive of higher local recurrence and poorer survival in oral cavity squamous cell carcinoma (OCSCC) patients. This study investigates whether aggressive WPOI can predict the mandibular invasion phenotype.

METHODS

Patients consecutively diagnosed with OCSCC undergoing a mandibulectomy (marginal or segmental) between 2013 and 2018 were reviewed. Senior physicians re-reviewed radiologic scans and pathologic slides of 44 cases.

RESULTS

Aggressive WPOI (WPOI-4, 5) is significantly associated with infiltrative bone invasion. Non-aggressive WPOI (WPOI-1, 2, 3) is significantly associated with the absence of bone invasion.

CONCLUSIONS

WPOI has become a useful tool that further characterizes the biologic behavior of OCSCC. Potentially, planned surgery may escalate from a marginal to segmental mandibulectomy based on aggressive WPOI for patients with radiographically uncertain cortical status. Further studies are needed to validate the relationship between OCSCC WPOI and mandible status.

Maxillary sinus osteoma: A case report and literature review

This case report describes a rare presentation of an osteoma in the maxillary sinus picked up from an incidental finding on an orthopantomogram that was obtained to inform orthodontic treatment. While orthodontists principally use this radiograph to assess the developing dentition, aid treatment planning and monitor treatment, several peripheral anatomical sites are evident on this radiograph. We review the literature in relation to osteomas presenting in the craniofacial area along with its management. We provide examples of common radiopaque lesions along with their radiographic features that dental healthcare clinicians may encounter.

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.

An Unusual Case of Mandibular Squamous Cell Carcinoma in Intimacy with an Impacted Wisdom Tooth

Squamous cell carcinoma is the most common head and neck malignancy. It can occur in the mandible or maxilla without a preexisting oral mucosal lesion. Often, the clinical and radiographic presentation of SCC directs the clinician to favour malignancy over other pathological conditions. However, SCC may also mimic an infectious condition and therefore can pose a diagnostic challenge even for the most experienced clinicians. Herein, we report a case of mandibular squamous cell carcinoma in a 53-year-old male who presented with symptoms of right facial swelling, trismus, pain, and right-sided lip paresthesia. The patient underwent a surgical removal of the presumed infected third molar of the right mandible, but histopathological analysis of the associated soft tissue unexpectedly yielded squamous cell carcinoma. Given the biopsy-proven diagnosis, the patient received a mandibular resection of the tumor followed by primary reconstruction with a fibular free flap. Patients presenting with symptoms mimicking odontogenic infections should receive vigilant attention by clinicians with regard to the disease history, clinical signs, radiographic evidence, and decision for histopathological analysis. This is especially true in the context of impacted dentition, where malignancy must be considered when formulating a differential diagnosis.

Performance of different imaging techniques in the diagnosis of head and neck cancer mandibular invasion: A systematic review and meta-analysis

BACKGROUND

To assess diagnostic efficacy of imaging techniques for mandibular invasion by head and neck cancer.

METHODS

Thirteen databases were searched. Study inclusion, data-extraction and quality assessment were performed independently. STATA 14.0 were mainly used for meta-analysis.

RESULTS

Forty-nine studies were included. For mandibular invasion (cortex and marrow), CBCT, SPECT, CT, MRI, orthopantomography, PET-CT and bone-scintigraphy showed pooled sensitivities of 90%, 97%, 73%, 88%, 75%, 90%, 92%, specificities of 85%, 69% 91%, 90%, 83%, 89%, 79%, AUC of 0.9461, 0.9434, 0.8995, 0.9296, 0.8761, 0.9290, 0.9207, respectively. The combined SROC curves indicated CBCT and SPECT were superior to other techniques. For mandibular medullary invasion (marrow), CT and MRI showed pooled sensitivities of 85% and 93%, specificities of 86% and 84%.

CONCLUSIONS

CBCT was top-priority choice for bone invasion diagnosis. SPECT was recommended for exclusion, CT and MRI were suitable for conformation. Further investigations are needed for mandibular medullary involvement.

Loss of RUNX3 expression inhibits bone invasion of oral squamous cell carcinoma

High recurrence and lower survival rates in patients with oral squamous cell carcinoma (OSCC) are associated with its bone invasion. We identified the oncogenic role of RUNX3 during bone invasion by OSCC. Tumor growth and the generation of osteolytic lesions were significantly inhibited in mice that were subcutaneously inoculated with RUNX3-knockdown human OSCC cells. RUNX3 knockdown enhanced TGF-β-induced growth arrest and inhibited OSCC cell migration and invasion in the absence or presence of transforming growth factor-β (TGF-β), a major growth factor abundant in the bone microenvironment. RUNX3 knockdown induced cell cycle arrest at the G1 and G2 phases and promoted G2 arrest by TGF-β in Ca9.22 OSCC cells. RUNX3 knockdown also inhibited both the basal and TGF-β-induced epithelial-to-mesenchymal transition by increasing E-cadherin expression and suppressing the nuclear translocation of β-catenin. In addition, the expression and TGF-β-mediated induction of parathyroid hormone-related protein (PTHrP), one of key osteolytic factors, was blocked in RUNX3-knockdown OSCC cells. Furthermore, treating human osteoblastic cells with conditioned medium derived from RUNX3-knockdown OSCC cells reduced the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoprotegerin ratio compared with treatment with conditioned medium from RUNX3-expressing cells. These findings indicate that RUNX3 expression in OSCC cells contributes to their bone invasion and the resulting osteolysis by inducing their malignant behaviors and production of osteolytic factors. RUNX3 alone or in combination with TGF-β and PTHrP may be a useful predictive biomarker and therapeutic target for bone invasion by oral cancer.

The novel IκB kinase β inhibitor IMD-0560 prevents bone invasion by oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) cells display significantly augmented nuclear factor-κB (NF-κB) activity, and inhibiting this activity suppresses malignant tumor characteristics. Thus, we evaluated the effect of IMD-0560, a novel inhibitor of IκB kinase (IKK) β that is under assessment in a clinical trial of rheumatoid arthritis, on bone invasion by the mouse OSCC cell line SCCVII. We examined the inhibitory effects of IMD-0560 on NF-κB activity and tumor invasion using human OSCC cell lines and SCCVII cells in vitro. Using a mouse model of jaw bone invasion by SCCVII cells, we assessed the inhibitory effect of IMD-0560 on jaw bone invasion, tumor growth, and matrix degradation in vivo. IMD-0560 suppressed the nuclear translocation of NF-κB and the degradation of IκBα in OSCC cells. IMD-0560 also inhibited invasion by suppressing matrix metalloproteinase-9 (MMP-9) production in OSCC cells. IMD-0560 protected against zygoma and mandible destruction by SCCVII cells, reduced the number of osteoclasts by inhibiting receptor activator of NF-κB ligand (RANKL) expression in osteoblastic cells and SCCVII cells, increased SCCVII cell death and suppressed cell proliferation and MMP-9 production in SCCVII cells. Based on these results, IMD-0560 may represent a new therapeutic agent for bone invasion by OSCC cells.

Magnetic resonance imaging for diagnosis of mandibular involvement from head and neck cancers: a systematic review and meta-analysis

Background

Diagnosis of mandibular involvement caused by head and neck cancers is critical for treatment. We performed a meta-analysis to determine the diagnostic efficacy of MR for distinguishing mandibular involvement caused by head and neck cancers.

Methods

Thirteen databases were searched electronically and hand-searching was also done. Two reviewers conducted study inclusion, data extractions, and quality assessment of the studies independently. Meta-disc 1.4 and STATA 11.0 were used to conduct the meta-analysis.

Results

16 studies involving a total of 490 participants underwent MR examinations and were accounted for in this meta-analysis. Among the included studies, 2 had high risk of bias, while the rest had unclear risk of bias. Meta-regression showed that the slight clinical and methodological heterogeneities did not influence the outcome (P>0.05). Meta-analysis indicated that the MR for the diagnosis of mandibular involvement had a pooled sensitivity (SEN) of 78%, specificity (SPE) of 83%, positive likelihood ratio (+LR) of 3.80, negative likelihood ratio (-LR) of 0.28, diagnostic odds ratio (DOR) of 28.94, area under curve (AUC) of 0.9110, and Q* of 0.8432. Two studies detected the diagnostic efficacy of MR for the mandibular medullar invasion, and only one study reported the inferior alveolar canal invasion, which made it impossible to include it in our meta-analysis. In comparing to CT, MR had a higher SEN without statistical significance (P = 0.08), but a significantly lower SPE (P = 0.04). The synthesized diagnostic efficacy (AUC and Q*) on mandibular involvement was similar between the two modalities (P>0.05).

Conclusions

Present clinical evidence showed that MR had an acceptable diagnostic value in detecting mandibular involvement caused by head and neck cancers. MR exceeded CT in diagnosing patients with mandibular invasion (higher sensitivity than CT) but was less efficacious to exclude patients without the mandibular invasion (lower specificity than CT).

Zoledronic acid and irradiation in oral squamous cell carcinoma

OBJECTIVE

This in vitro study evaluated cytotoxicity and cell migration effects of zoledronic acid and irradiation upon oral squamous cell carcinoma.

MATERIALS AND METHODS

Zoledronic acid was administrated at doses of 10, 25, 50, and 100 μM to PE/CA-PJ15 oral squamous cell carcinoma cultures, irradiated with different doses (0, 5, 15, and 30 Gy), followed by evaluation of the effects on cell viability. Cell migration capacity was studied after 24- and 72-h incubation.

RESULTS

At 24 h, the 100 μM concentration of zoledronic acid combined with 15 Gy irradiation caused the greatest decrease in cell viability. At 72 h, statistically significant decreases in cell viability were found with all concentrations of zoledronic acid with or without irradiation: 0 Gy (P < 0.001), 5 Gy (P < 0.001), 15 Gy (P < 0.001), and 30 Gy (P < 0.001). 50 μM and 100 μM doses of zoledronic acid combined with 5 Gy irradiation yielded the greatest decrease in cell migration capacity.

CONCLUSIONS

Zoledronic acid increases cytotoxic activity in the PE/CA-PJ15 cell line and reduces cell migration capacity. These findings suggest that combination therapy using biphosphates and radiation may offer a promising therapy.

Evaluation of intraoperative cytological assessment of bone resection margins in patients with oral squamous cell carcinoma

BACKGROUND

Frozen sections are routinely applied to control for adequate resection margins. In cases in which carcinoma infiltrates bone, the intraoperative microscopic assessment of bone margins remains challenging due to technical difficulties to section native bone. The objective of the current study was to evaluate an intraoperative cytological approach to control bone resection margins in patients with bone-infiltrating oral squamous cell carcinomas.

METHODS

A total of 174 cytological preparations obtained from bone margins of bone-infiltrating oral squamous cell carcinomas (28 patients) were assessed intraoperatively and compared with the corresponding histological findings. In a validation cohort (45 patients) the intraoperative cytological assessment of bone resection margins (ICAB) (104 margins) was evaluated as a diagnostic tool for routine clinical application.

RESULTS

In the first patient cohort, the ICAB revealed 95.3% sensitivity and 96% specificity. The results provided an accuracy of 95.7% with a significant correlation noted between cytological and histological results (κ, 0.91; P < .001), and a positive predictive value and negative predictive value of 93.8% and 96.9%, respectively. In the validation cohort, ICAB revealed 80% sensitivity and 98.9% specificity with 98% accuracy. There was a significant correlation found between cytological and histological results (κ, 0.91; P < .001), providing a positive predictive value and negative predictive value of 80% and 98%, respectively. ICAB could predict final resection status at bone margins with 80% sensitivity and 97.5% specificity. A significant correlation was found between the cytological and histological resection status at bone margins (κ, 0,75; P < .001).

CONCLUSIONS

ICAB could supplement intraoperative frozen sections of soft tissue margins as a standard procedure to control for adequate resection at bone margins.

Imaging in oral cancers

Oral cavity squamous cell cancers form a significant percentage of the cancers seen in India. While clinical examination allows direct visualization, it cannot evaluate deep extension of disease. Cross-sectional imaging has become the cornerstone in the pretreatment evaluation of these cancers and provides accurate information about the extent and depth of disease that can help decide the appropriate management strategy and indicate prognosis. Early cancers are treated with a single modality, either surgery or radiotherapy while advanced cancers are offered a combination of surgery, radiotherapy and chemotherapy. Imaging can decide resectability, help plan the precise extent of resection, and indicate whether organ conservation therapy should be offered. Quality of life issues necessitate preservation of form and function and pretreatment imaging helps plan appropriate reconstruction and counsel patients regarding lifestyle changes. Oral cavity has several subsites and the focus of the review is squamous cancers of the gingivobuccal region, oral tongue and retromolar trigone as these are most frequently encountered in the subcontinent. References for this review were identified by searching Medline and PubMed databases. Only articles published in English language literature were selected. This review aims to familiarize the radiologist with the relevant anatomy of the oral cavity, discuss the specific issues that influence prognosis and management at the above subsites, the optimal imaging methods, the role of imaging in accurately staging these cancers and in influencing management. A checklist for reporting will emphasize the information to be conveyed by the radiologist.

Mandibular conservation in oral cancer

Surgery is one of the established modes of initial definitive treatment for a majority of oral cancers. Invasion of bony or cartilaginous structures by advanced upper aero-digestive tract cancer has been considered an indication for primary surgery on the basis of historic experience of poor responsiveness to radiation therapy [1]. The mandible is a key structure both in the pathology of intra-oral tumours and their surgical management. It bars easy surgical access to the oral cavity, yet maintaining its integrity is vital for function and cosmesis. Management of tumours that involve or abut the mandible requires specific understanding of the pattern of spread and routes of tumour invasion into the mandible. This facilitates the employment of mandibular sparing approaches like marginal mandibulectomy and mandibulotomy, as opposed to segmental or hemimandibulectomy which causes severe functional problems, as the mandibular continuity is lost. Accurate preoperative assessment that combines clinical examination and imaging along with the understanding of the pattern of spread and routes of invasion is essential in deciding the appropriate level and extent of mandibular resection in oral squamous cell carcinoma. Studies have shown that local control rates achieved with marginal mandibulectomy are comparable with that of segmental mandibulectomy. In carefully selected patients, marginal mandibulectomy is an oncologically safe procedure to achieve good local control and provides a better quality of life. This article aims to review the mechanism of spread, evaluation and prognosis of mandibular invasion, various techniques and role of mandibular conservation in oral squamous cell carcinoma.

The role of tumor invasion into the mandible of oral squamous cell carcinoma

PURPOSE

The aim of this study was to determine the prognostic impact of the extent of bone invasion in patients undergoing mandibulectomy for oral squamous cell carcinoma (OSCC), and to evaluate the relation between clinicopathologic parameters and outcome.

METHODS

Nine hundred and eighty-two patients presented with OSCC and 334 were treated surgically by some form of mandibular excision. Treatment included marginal, rim, or segmental mandibulectomy depending on the clinical and radiological observation of the mandible and suspected bone invasion. Kaplan-Meier plots and univariate log-rank test and multivariate Cox proportional hazards regression models were used to determine the association between possible predictor variables and survival time.

RESULTS

After controlling for age, tumor and nodal stage, UICC stage, type of reconstruction, which were independent predictors of survival, type of mandibulectomy was significantly associated with survival in the univariate analysis (P = 0.038), whereas bone invasion was not in both univariate and multivariate analysis. The rate of bone invasion detected after marginal mandibulectomy was 15.5%, in rim resections 50%, and segmental mandibulectomy at 84.7%. Recurrence of OSCC was found to be associated with overall survival (P = 0.039).

CONCLUSIONS

If bone invasion is identified histologically in a resected specimen, the prognosis is not worsened and additional surgery need not be undertaken in adequately resected margins. Although the mandible should be preserved if feasible, the choice of treatment should always provide safe resection margin. The high rates of unsuspected bone invasion found in this study should be kept in mind in patients with OSCC close to the mandible.

Predictors of mandibular involvement in cancers of the oromandibular region

PURPOSE

Invasion of the mandible by oral squamous carcinoma is not only a relative contraindication to mandible conservation but also an indicator of poor prognosis. This study looks at clinical, radiologic, and operative variables that may help in predicting mandibular bone involvement.

PATIENTS AND METHODS

A prospective study was carried out to evaluate the mandibular involvement and its predictors in 51 cases of oral squamous carcinoma located in the mandibular region. All patients underwent segmental- or hemimandibulectomy. A detailed clinical examination was followed by radiologic assessment and operative assessment. Statistic analysis was carried out by chi(2) test (odds ratio [OR] with a significance level of 5%). Multivariate analysis was carried out by logistic regression analysis.

RESULTS

Univariate analysis identified location of tumor on lower alveolus (OR = 8.5), sensory disturbances of inferior alveolar nerve (OR = 16.2), location of tumor within 1 cm of mandible (OR = 1.4), presence of findings on periosteal striping (OR = 2.0) like subperiosteal reaction (OR = 3.5), cortical expansion (OR = 8.8) and presence of pathologic fracture (OR = 2.3) as predictor of bone invasion. Grade of tumor (P = .05) and radiologic bone involvement (P = .02) were found to be significant independent predictors of pathologic bone involvement on multivariate analysis.

CONCLUSIONS

It is possible to identify mandibular invasion in almost all cases of oral squamous carcinoma by combining clinical examination, radiologic findings, and findings on periosteal stripping. This helps surgeons to make an informed preoperative and intraoperative decision about mandibular conservation. However, one should be careful when evaluating bone involvement on periosteal stripping as this cannot be recommended as a method of choice due to fear of tumor dissemination and violation of oncologic principles.

Patterns of mandibular invasion in oral squamous cell carcinoma of the mandibular region

BACKGROUND

Mandibular resections are routinely carried out for achieving a R0 resection for oral cancers. However, the need of mandibular resection to achieve this has always been questioned. The present study was carried out to define the pattern of mandibular involvement in carcinoma of the mandibular region.

PATIENTS AND METHODS

A total of 25 consecutive patients who had undergone mandibular resection and were found to have mandibular invasion were studied in a prospective open fashion. After decalcification the specimens were serially sectioned at 1 cm interval to identify invasion of mandibular bone. Type of invasion, route of spread and host cell reactions were also recorded.

RESULTS

The mandibular involvement was infiltrative in 14(56%) and erosive in 11(44%). It was cortical in 5(20%), marrow involvement was seen in 15(60%) while 5(20%) had spread through the inferior alveolar canal. Of the 25, 24(96%) lesions were located with in 1 cm of the mandible.

CONCLUSION

The possibility of mandibular involvement is higher in patients where tumours are located with in 1 cm of the mandible. Involvement of mandible through the canal of inferior alveolar nerve in the present study was relatively high (20%). Therefore it is recommended that before a decision is taken to preserve the mandible it should be thoroughly screened for possible involvement.

A new guide to mandibular resection for oral squamous cell carcinoma based on the Cawood and Howell classification of the mandible

A new guide for mandibular resection in the management of oral squamous cell carcinoma based on the Cawood and Howell classification of the jaws is suggested. This was a retrospective review of case records and pre-operative orthopantomograms (OPG), bone scintigraphy and magnetic resonance imaging (MRI). The classification of the mandible was based on the residual bone height as measured in the molar region of the OPG to be equivalent to the Cawood and Howell classification of the mandible (Class I-II dentate or immediate post-extraction), Class III-IV >20mm well-rounded or knife-edge ridge, and Class V-VI <20mm (flat or depressed ridge form). Of the 77 patients, 58% (22/38) of Class I-II, 43% (9/23) of Class III-IV and 6% (1/16) of Class V-VI were treated with a marginal (rim) resection of the mandible. The predictability of the pre-operative investigations was more accurate in the edentulous mandible (Class III-VI). A simple guide is suggested for mandibular resection taking into account the pre-operative investigations, the estimation of invasion clinically, and the Cawood and Howell classification of ridge resorption.