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

Abstract

PurposeTo 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).MethodsThis 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.ResultsA 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.ConclusionsFor 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.

Assessment of the Electrolyte Heterogeneity of Tissues in Mandibular Bone-Infiltrating Head and Neck Cancer Using Laser-Induced Breakdown Spectroscopy

“…Direct tumor invasion through the bone is the most common scenario [ 32 ] and can be accurately covered by LIBS-based differentiation of healthy bone and bone-infiltrating tumor tissue, as previously shown [ 20 ]. However, 20% of bone-infiltrating tumors grow along the inferior alveolar nerve [ 32 ], and 43% of all bone-infiltrating tumors exhibit radiological involvement of the bony nerve canal, which is associated with poor survival [ 37 ]. According to the interpretation of the current study results, LIBS-based tissue discrimination appears to ensure the differentiation between cell-rich tumor areas and the inferior alveolar nerve with a sensitivity of ≥95.2% and a specificity of ≥87.2%, based on the intracellular detection of Ca and K. In the concrete intraoperative implementation of LIBS-guided feedback control, the performance of pairwise tissue discrimination would ultimately have to be summarized on a metric scale, as shown in this study.…”

Cortical microarchitecture and remodeling-associated gene expression related to oral cancer prognosis

“…However, the review concluded that cortical involvement alone did not decrease OS but only the medullary involvement had such an effect. t 27 Mahajan et al, 28 in a new proposal for a staging classification, observed that cortical bone erosion may not affect survival and that only medullary invasion affects prognosis. In our study, among the 24 cases, 8 had bone involvement, and only 2 patients had verified complete medullary invasion.…”

Imaging Recommendations for Diagnosis, Staging, and Management of Oral Cancer

“…Surgical resection is possible in disease with involvement of low infratemporal fossa (ITF) or retroantral ITF and superficial or deep cortical bony erosion. 18 26 Detailed explanation of the all the above entities is beyond the scope of this article. CECT has its own disadvantages like less soft tissue resolution compared to CE-MRI, which can be used as a problem-solving tool in detecting subtle lesions, or for demonstrating perineural or intracranial spread.…”