Margin to Depth of Invasion Ratio: A Significant Predictor of Survival in Patients With Oral Cancer

Margin to depth of invasion ratio as an indicator for stratifying close margins in early-stage oral squamous cell carcinoma

OBJECTIVES

In early-stage oral squamous cell carcinoma (OSCC) patients, whether the margin-to-depth-of-invasion ratio (MDR) can assist in stratifying the prognosis remains unclear.

METHODS

Patients diagnosed with early stage OSCC at National Taiwan University Hospital between January 2007 and December 2021 were reviewed. Patients with margin > 1 mm were classified into two groups: MDR < 0.5 and MDR ≥ 0.5.

RESULTS

We analyzed 911 pT1-2N0M0 OSCC patients, 723 (79.36 %) with MDR ≥ 0.5 and 188 (20.64 %) with MDR < 0.5. Patients in the MDR < 0.5 group displayed a significantly higher local recurrence rate (odds ratio 2.81, p = 0.002) compared with MDR ≥ 0.5 group. The 5-year disease-free survival were 80.8 % for clear margin, 76.3 % for close margin (MDR ≥ 0.5), and 65.2 % for close margin (MDR < 0.5). The overall survival displayed a similar pattern, with 5-year rates of 88.3 % for clear margin, 86.8 % for close margin (MDR ≥ 0.5), and 75.0 % for close margin (MDR < 0.5). There were no significant overall survival differences between the two MDR ≥ 0.5 groups, but both were significantly superior to patients with MDR < 0.5 (p = 0.001; p = 0.01). After multivariant cox analysis, MDR < 0.5 was a significant risk factor for disease-free survival (p < 0.001).

CONCLUSION

For early stage OSCC patients without positive margin (≦1mm), the survival outcome between MDR ≥ 0.5 group and MDR < 0.5 group was significantly different. The MDR < 0.5 group had significantly higher risk of local recurrence that may warrant adjuvant treatment.

Enhancing oral squamous cell carcinoma prediction: the prognostic power of the worst pattern of invasion and the limited impact of molecular resection margins

Objective

Oral squamous cell carcinoma (OSCC) originates from the mucosal lining of the oral cavity. Almost half of newly diagnosed cases are classified as advanced stage IV disease, which makes resection difficult. In this study, we investigated the pathological features and mutation profiles of tumor margins in OSCC.

Methods

We performed hierarchical clustering of principal components to identify distinct patterns of tumor growth and their association with patient prognosis. We also used next-generation sequencing to analyze somatic mutations in tumor and marginal tissue samples.

Results

Our analyses uncovered that the grade of worst pattern of invasion (WPOI) is strongly associated with depth of invasion and patient survival in multivariable analysis. Mutations were primarily detected in the DNA isolated from tumors, but several mutations were also identified in marginal tissue. In total, we uncovered 29 mutated genes, mainly tumor suppressor genes involved in DNA repair including BRCA genes; however none of these mutations significantly correlated with a higher chance of relapse in our medium-size cohort. Some resection margins that appeared histologically normal harbored tumorigenic mutations in TP53 and CDKN2A genes.

Conclusion

Even histologically normal margins may contain molecular alterations that are not detectable by conventional histopathological methods, but NCCN classification system still outperforms other methods in the prediction of the probability of disease relapse.