Pre-surgical assessment of mandibular bone invasion from oral cancer: comparison between different imaging techniques and relevance of radiologist expertise

[On the relevance of histopathology results in oropharyngeal cancer with mandibular involvement and the necessary imaging]

BACKGROUND

Planning of surgical procedures in patients suffering from oropharyngeal cancer requires appropriate imaging, particularly in consideration of the spatial relationship to the mandible. Resection of portions of the mandible (box, marginal, or segmental resection) is often necessary, while simultaneously avoiding overtreatment. Typically, a computed tomography (CT) scan is initially performed. However, the question arises of whether CT alone is adequate for reliable assessment of mandibular involvement.

MATERIALS AND METHODS

A patient cohort of 25 individuals aged 44-79 years (mean 62 years) undergoing partial oropharyngeal resection with segmental mandibular resection was examined. The indication for segmental resection was based on the close relationship of the tumor to the mandible observed in imaging. Reconstruction was consistently carried out with a reconstruction plate and free or pedicled flaps. Preoperative radiological findings were compared with histopathology results after decalcification of the mandibular bone.

RESULTS

Cortical tumor infiltration was observed in the mandible in 9 patients (36%). Preoperatively, clear bone infiltration had been identified in CT in only 2 of these 9 patients; in the remaining 7, only direct tumor contact with the mandible was evident. Magnetic resonance imaging (MRI) revealed bone infiltration in 1 of these 7 patients.

DISCUSSION

Adhering to safety margins requires a radical surgical approach and reliable intraoperative frozen section analysis. However, at the bone level, intraoperative frozen section analysis is technically impractical due to the required decalcification. Only after decalcification can the entire specimen be assessed for tumor infiltration. In our cohort, a significant discrepancy in terms of bone infiltration was noted between preoperative imaging assessments and postoperative histopathology. CT preoperatively identified bone infiltration in only 8% of our patients. In two thirds of the specimens, no bone infiltration was evident after decalcification and histopathological processing, retrospectively indicating overtreatment by segmental resection; box or marginal resections may have been sufficient in these cases. Therefore, when tumors are adjacent to the bone in CT, MRI should also be performed preoperatively to more reliably detect bone infiltration.

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.

Functional and esthetic outcomes of virtual surgical planning versus the conventional technique in mandibular reconstruction with a free fibula flap: A retrospective study of 24 cases

This study aimed to compare the functional and esthetic results in patients following mandibular reconstruction with a free fibula flap (FFF) by virtual surgical planning (VSP) versus the conventional technique. Patients who had undergone mandibular reconstruction with a FFF by VSP or the conventional technique were retrospectively assessed. The two groups were compared regarding functional and esthetic variables with appropriate scales preoperatively, intraoperatively, and postoperatively. Twenty-four patients were evaluated in two groups: conventional (n = 8) and VSP (n = 16). The mean amount of mandibular asymmetry was 2.62 mm (SD = 1.59) in the conventional group and 1.19 mm (SD = 1.32) in the VSP group. Of the patients who underwent conventional surgery, 12.5% had mandibular asymmetry of <2 mm and 87.5% had asymmetry of 2-5 mm. Of the VSP patients, 61.5% had mandibular asymmetry of <2 mm and 38.5% had mandibular asymmetry of 2-5 mm (p = 0.03). The mean difference in size of mandibular angle on the surgical and control sides was not significantly different between the two groups (p = 0.62). The difference in mean length of the mandibular body on the surgical side relative to the control side was not significant between the two groups (p = 0.75). Differences in functional variables between the two groups were not significant. Within the limitation of the study, it seems that the VSP technique resulted in better facial symmetry and superior esthetic outcomes compared with the conventional technique.

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.

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.

Surgical Management of Granular Cell Tumor of the Orbit: Case Report and Literature Review

Introduction:

Granular Cell Tumors (GCTs) of the orbit are rare-entity soft-tissue tumors, and few reports have been published in the literature. The treatment of the choice is total excision. Early diagnosis prior to surgery is valuable for the distinction of malignant from benign tumor.

Case presentation:

We report a case of a 55-year-old woman with a solitary slow-growing mass in the right orbit with the involvement of the rectus inferior muscle, and present a review of the recent literature. The lesion had a diameter of 1 cm and was noticed 2 years before the examination. Excisional biopsy confirmed the diagnosis of GCT. The tumor was resected through a retroseptal transconjunctival approach. The final histological examination revealed findings characteristic of GCT, including positive reaction for protein S-100, SOX10, and calcitonin and negative reaction for desmin, myogenin, Smooth Muscle Antigen (SMA), Melan-A, and HMB-45. There were no signs of malignancy in this sample. Disturbance of motility was not noted by the patient after surgery.

Conclusion:

GCT should be included in the differential diagnosis of intraorbital lesions, particularly those that involve the orbit muscles. A biopsy is recommended before surgical resection, to exclude malignancy and prevent radical resection.