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

Assessment of the bony resection margin distance in bone-invasive oral cancer using laser-induced breakdown spectroscopy

OBJECTIVES

Inadequate resection margins of less than 5 mm impair local tumor control. This weak point in oncological safety is exacerbated in bone-infiltrating tumors because rapid bone analysis procedures do not exist. This study aims to assess the bony resection margin status of bone-invasive oral cancer using laser-induced breakdown spectroscopy (LIBS).

MATERIALS AND METHODS

LIBS experiments were performed on natively lasered, tumor-infiltrated mandibular cross-sections from 10 patients. In total, 5,336 spectra were recorded at defined distances from the tumor border. Resection margins < 1 mm were defined as very close, from 1-5 mm as close, and > 5 mm as clear. The spectra were histologically validated. Based on the LIBS spectra, the discriminatory power of potassium (K) and soluble calcium (Ca) between bone-infiltrating tumor tissue and very close, close, and clear resection margins was determined.

RESULTS

LIBS-derived electrolyte emission values of K and soluble Ca as well as histological parameters for bone neogenesis/fibrosis and lymphocyte/macrophage infiltrates differ significantly between bone-infiltrating tumor tissue spectra and healthy bone spectra from very close, close, and clear resection margins (p < 0.0001). Using LIBS, the transition from very close resection margins to bone-infiltrating tumor tissue can be determined with a sensitivity of 95.0%, and the transition from clear to close resection margins can be determined with a sensitivity of 85.3%.

CONCLUSIONS

LIBS can reliably determine the boundary of bone-infiltrating tumors and might provide an orientation for determining a clear resection margin.

CLINICAL RELEVANCE

LIBS could facilitate intraoperative decision-making and avoid inadequate resection margins in bone-invasive oral cancer.

Evaluation of outcomes after conservative mandibular surgery in patients with oral squamous cell carcinoma

This study aimed to assess preoperative radiological and clinical examinations for identifying bone status and to evaluate survival outcomes in patients undergoing marginal mandibulectomy for the primary treatment of oral squamous cell carcinoma. The medical records, enhanced computed tomography (CT) scans, and pathological specimens of these patients were reviewed. Disease-free (DFS), local recurrence-free (LRFS), and osteoradionecrosis-free (ORNFS) survival were analysed. The study included 104 patients. The preoperative CT and clinical examinations achieved a sensitivity of 45.8% and specificity of 100% for judging bone condition. LRFS was 79.6% and DFS was 68.8%. Pathological bone invasion in significantly affected DFS (P = 0.597), while DFS was significantly higher for those with a lower clinical tumour stage (1/2 vs 3/4; P = 0.005) and postoperative radiotherapy (P = 0.011). Among 39 patients receiving postoperative radiotherapy, ORNFS was 75.2%. Postoperative chemotherapy significantly decreased ORNFS (P = 0.009). Tumour subsite (P = 0.003) and the resection site (P = 0.035) significantly affected the remaining bone height. The results indicate that CT and clinical examinations cannot precisely identify superficial bone damage, but work well in selecting patients for marginal resection. Adhering to current indications, this resection approach can guarantee safe bone margins in terms of survival outcomes.

Marginal versus Segmental Mandibulectomy in the Treatment of Oral Cavity Cancer: A Systematic Review and Meta-analysis

Introduction  Oral cavity squamous cell carcinoma (OCSCC) is the most common malignancy in the oral cavity. Two types of mandibular resections have been described: the segmental mandibulectomy and the marginal mandibulectomy. Both may have a different impact over the quality of life, oncological prognosis, and functional or aesthetic result. Objectives  The aim of this study was to systematically explore the literature to determine the survival outcomes and disease control rates in patients who underwent segmental or marginal mandibulectomy for OCSCC with histological evidence of cortical and medullary bone invasion. Data Synthesis  This review involved a systematic search of the electronic databases MEDLINE/PUBMED, Google Scholar, Ovid Medline, Embase, and Scopus including articles from 1985 to 2019. Fifteen articles were included for qualitative analysis and 11 articles were considered for meta-analysis calculations. All of them correspond to retrospective cohort studies. Conclusion  This systematic review reveals the low-level evidence regarding the impact over local control or survival according to the type of mandibulectomy. Our results need to be considered with precaution according to the limited evidence available. We just found difference regarding the 5-year disease-free survival, and a tendency in favor of segmental mandibulectomy was confirmed when medullary invasion was evident.

Clinical outcomes of teeth adjacent to the site of mandibulotomy or mandibulectomy in patients with head and neck cancer: results from a multidisciplinary mono-institutional head and neck tumor board

INTRODUCTION

The aim of this case series was to evaluate the necrosis of teeth adjacent to the site of mandibulotomy or mandibulectomy in a cohort of patients suffering from head and neck cancers.

METHODS

Fourteen patients who underwent segmental mandibulectomy or paramedian mandibulotomy for oral, oropharynx or major salivary gland cancer and a total of 23 teeth were included in this case series. Twelve patients underwent adjuvant head and neck radiotherapy. Cold sensitivity pulp testing and/or electric pulp testing were performed on teeth at the margin of mandibulectomy and on teeth adjacent to mandibulotomy after surgery. A "positive" response was considered the healthy state, and "negative" was considered the diseased state of the tooth.

RESULTS

The 10 patients who underwent mandibulotomy had 12 teeth with a negative response. The 4 patients treated by mandibulectomy had two positive and three negative responses to cold and electric pulp tests. Fifteen out of 23 teeth (65.2%) showed a negative response to sensitivity testing.

CONCLUSIONS

Tooth necrosis seems to be a common event after mandibulectomy and mandibulotomy.

CLINICAL RELEVANCE

To avoid post-surgery complications, performing root canal therapy before surgery on the teeth adjacent to the surgical site could be an appropriate strategy.

Factors associated with survival and patient's quality of life after segmental mandibulectomy

AIM

This study aimed to explore the survival rate and quality of life (QoL) in patients who underwent segmental mandibulectomy and determine the associated factor with survival rate and QoL.

MATERIAL AND METHODS

In this cross-sectional study, all patients who underwent segmental mandibular resection in the referral center of Shiraz University of Medical Sciences, Iran, during 2015-2019 were included. Inclusion criteria were segmental mandibulectomy due to any pathology and age of more than 8 years old. Demographic, clinical data and patient survival were recorded. EORTC QLQ-HN43 was used to evaluate QoL.

RESULTS

Totally, 82 patients were studied. The overall 3-year survival rate was 69.5% (57 patients) (mean ± SD: 1.35 ± 1.03 years). According to univariate analysis, age (p-value = 0.001), hospital lengths of stay (p-value < 0.001), gender (p-value = 0.014, OR = 4.143), education (p-value = 0.015, OR = 0.291), pathology (p-value < 0.001, OR = 17.000), metastasis (p-value = 0.018, OR = 4.894), neck dissection (p-value < 0.001, OR = 52.381), frozen margin (p-value < 0.001 OR = 8.000), recurrence (p-value = 0.001, OR = 6.273), and status of chemoradiotherapy (p-value < 0.001) were significantly associated with survival rate. Logistic regression revealed that survival was associated with gender (p-value = 0.040, OR = 23.689), level of education (p-value = 0.019, OR = 0.019), and neck dissection (p-value = 0.019, OR = 175.781). According to univariate analysis, pathology (p-value = 0.003), neck dissection (p-value = 0.024), frozen margin (p-value = 0.004), and chemoradiotherapy (p-value = 0.026) were significantly associated with QoL. Linear regression revealed that QoL was associated with none of the measured factors.

CONCLUSION

In conclusion, gender, level of education, and neck dissection were related to 3-year patients' survival. None of the measured factors in this study were associated with QoL.

Real-time detection of bone-invasive oral cancer with laser-induced breakdown spectroscopy: A proof-of-principle study

OBJECTIVES

Intraoperative definition of resection margin status in bone-invasive oral cancer is a fundamental problem in oncologic surgery due to the lack of rapid bone analysis methods. Laser-induced breakdown spectroscopy (LIBS) provides direct measurement with real-time examination of a minimal tissue sample. This proof-of-principle study aimed to evaluate the possibility of distinguishing tumorous and healthy areas with LIBS.

MATERIALS AND METHODS

LIBS experiments were executed on native segmental mandibulectomy specimens from 15 patients with bone-invasive oral cancer. Normalized and intensity-matched spectra were compared. Under biological derivation, peak area calculation and principal component analysis (PCA) were applied. The discriminatory power of the PCAs was correlated with the architectural and cytological characteristics of the lasered tumor tissue. Receiver operating characteristics analysis was used to evaluate the performance of LIBS in the real-time detection of bone-invasive cancer.

RESULTS

Calcium (Ca), which is high in healthy bone, is replaced by potassium (K) and sodium (Na) in bone-invasive cancer. The degree of stromal induction is significantly correlated with the discriminatory power between healthy and tumorous spectra. In this study, LIBS ensured an overall sensitivity of 95.51% and a specificity of 98.64% via the intracellular detection of K and Na.

CONCLUSION

This study demonstrated robust real-time detection of bone-invasive oral cancer with LIBS, which may lay the foundation for establishing LIBS as a rapid bone analysis method. Further development of a LIBS-guided assessment of bone tumor resection margins might reduce the extent of bony resection without compromising oncologic safety.

Mechanical Fatigue Performance of Patient-Specific Polymer Plates in Oncologic Mandible Reconstruction

Mandible defects are conventionally reconstructed using titanium plates. However, titanium causes metallic artifacts which impair radiological imaging. This study aims at evaluating mechanical fatigue of radiolucent fiber-reinforced polyetheretherketone (f-PEEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polyphenylsulfone (PPSU) polymer plates for mandible reconstruction. A total of 30 plates (titanium [n = 6], f-PEEK [n = 6], PEEK [n = 6], PEKK [n = 6], PPSU [n = 6]) were implanted in synthetic mandibulectomized polyurethane mandibles. Servo-pneumatic mechanical testing with cyclic application of 30−300 N at 3 Hz was conducted. Bite forces were 70% on the unresected and 30% on the resected side. Total number of cycles was set to 250,000. Testing was aborted in case of plate or screw failure. Axial load to failure was tested with a speed of 1 mm/s. Kruskal−Wallis and Dunn’s post hoc tests were used. Titanium, f-PEEK, and PEEK showed no failure in fatigue testing and PPSU (p < 0.001) failed against titanium, f-PEEK, PEEK, and PEKK. Titanium allowed the highest load to failure compared to f-PEEK (p = 0.049), PEEK (p = 0.008), PEKK (p < 0.001), and PPSU (p = 0.007). f-PEEK, PEEK, and PEKK withstood expected physiological bite force. Although titanium plates provided the highest fatigue strength, f-PEEK and PEEK plates showed no failure over 250,000 chewing cycles indicating sufficient mechanical strength for mandible reconstruction.

Endoscopically Assisted Marginal Mandibulectomy Using an Intraoral Approach Alone for Squamous Cell Carcinoma of the Posterior Mandibular Gingiva: A Technical Note

Study Design

Technical note.

Objective

Marginal mandibulectomy is a surgical procedure for treatment of mandibular gingival tumors. The intraoral approach to the posterior region of the mandible for marginal mandibulectomy is difficult due to limited access and operating field visibility; the conventional surgical procedure may require some skin incisions. This report discusses the effectiveness of endoscopic assistance in marginal mandibulectomy.

Methods

This article describes endoscopically assisted marginal mandibulectomy using an intraoral approach alone for squamous cell carcinoma of the posterior mandibular gingiva.

Results

The advantages of this surgical method are twofold: (1) superior visibility to the lower edge of the mandible without any skin incision; and (2) safe surgical confirmation of important anatomy on the buccolingual side (e.g., mental foramen, lingual nerve, mandibular foramen, and neurovascular bundle). This minimally invasive approach without any skin incision, as well as the superior visibility of the operating field, are important advantages of endoscopically assisted marginal mandibulectomy that cannot be obtained by other surgical methods.

Conclusions

Endoscopically assisted marginal mandibulectomy using an intraoral approach alone may be useful because it avoids damage to facial skin and improves safety by employing an enlarged bright field.

Survival analysis of segmental mandibulectomy with immediate vascularized fibula flap reconstruction in stage IV oral squamous cell carcinoma patients

PURPOSE

This study aims to assess the survival rate of oral squamous cell carcinoma (OSCC) patients following immediate mandibular reconstruction with vascularized fibula flap (VFF) and to identify risk factors influencing the overall survival rate and postoperative outcomes.

PATIENTS AND METHODS

Patients suitable for the inclusion criterion diagnosed and treated between January 1996 till June 2019 for OSCC were retrospectively reviewed (n = 74). Potential risk factors and postoperative outcomes were recorded and analyzed.

RESULTS

The overall cumulative survival rate of patients was 0.52 at the end of 5th year. Overall, advanced pN stage (p = 0.0422), poor tumor differentiation (p < 0.0001), positive/close surgical margins (p = 0.0209), vascular invasion (p = 0.0395), perineural invasion (p = 0.0022) and tumor recurrence (p = 0.0232) were significantly related to a decreased cumulative survival. Tumor recurrence was significantly correlated with involvement of positive/close surgical margins, moderate (p = 0.0488), poor-differentiated tumors (p = 0.202), extracapsular spread (p = 0.0465), computer-assisted surgery (p = 0.0014) and early complications (p = 0.0224). Pain was significantly associated with the extracapsular spread (p = 0.0353) and early complications (p = 0.0127).

CONCLUSION

The five-year survival rate of advanced OSCC patients after segmental mandibulectomy with fibula free-flap reconstruction was 52.4%. Clinical/pathological risk factors such as the pN stage, tumor differentiation, surgical margins, vascular invasion, perineural invasion, tumor recurrence significantly influenced the overall cumulative survival rate.

Squamous cell carcinoma of the mandible - Patterns of metastasis and disease recurrence in dependence of localization and therapy

INTRODUCTION

Oral squamous cell carcinomas exhibit distinct patterns of disease progression, depending on their localisation. This study aimed to evaluate clinicopathological data in patients with tumors of the mandibular alveolar process, to facilitate risk assessment and therapy planning.

MATERIALS AND METHODS

A retrospective cohort study was designed including patients with squamous cell carcinoma of the mandibular gingiva. Clinical and pathological data were collected to determine the rate of cervical metastases and clinical outcomes depending on tumor stage, localization (anterior, intermediate and posterior) and the extent of tumor resection.

RESULTS

120 patients were included in the analysis. Rate of metastases was 42.6%. Tumors of the anterior part of the mandible exhibited significantly higher rates of bilateral metastases (anterior: 85.7%, intermediate: 15.8%, posterior: 4%, p < 0.001) and local recurrence (anterior: 25%, intermediate: 16.3%, posterior: 5.5%, p = 0.03) compared to posterior malignancies.

CONCLUSION

Tumors of the anterior segment of the mandible are characterized by high rates of metastases and local recurrence. Therefore, we propose radical segmental resection and bilateral neck dissection in those patients.