The aim of this paper was to characterise the isotopic composition of oral squamous cell carcinoma (OSCC) specimens of different areas of the oral cavity. Secondly, we assessed whether there was a correlation between clinical stages of OSCC and isotopic abundance. The IRMS procedure was performed on 124 samples derived from 31 patients with OSCC of 15 N and 13 C to assess the isotopic composition. From each individual, four samples from the tumour, two from the margins, and two samples of healthy oral mucous membranes were derived. The two samples from the tumour and two samples from the margin were additionally subjected to histopathological assessment. Then, statistical analysis was conducted. Tumour infiltration tissues of the lower lip were characterised by higher mean δ¹³C values compared to samples derived from cancers of the other oral cavity regions (−23.82 ± 1.21 vs. −22.67 ± 1.35); (p = 0.04). The mean percentage of nitrogen content in tumour tissues was statistically higher in patients with the most advanced cancers (11.89 ± 0.03%) versus the group of patients with II and III stage cancers (11.12 ± 0.02%); (p = 0.04). In patients at stage IV, the mean δ¹³C value in the cancer samples equalled −22.69 ± 1.42 and was lower than that in patients at less severe clinical stages (p = 0.04). Lower lip cancer tissues differed in the isotopic abundance of carbon in comparison with tissues derived from the group of combined samples from other locations. Values of δ¹³C observed in specimens derived from lower lip cancers were similar to those observed in healthy oral mucous membranes. Cancer tissues obtained from patients in the last stage of OSCC had a different isotopic composition in comparison with those obtained from earlier stages. To confirm these observations, further research on larger groups of patients is needed.

Background: Cervical lymph node metastases are a major prognostic factor in patients with oral squamous cell carcinoma (OSCC). Despite advances in imaging, accurate preoperative prediction of nodal involvement remains a challenge. This study evaluated the utility of Isotope Ratio Mass Spectrometry (IRMS) in assessing the risk of lymph node metastases in patients with OSCC. We hypothesize that alterations in the abundance of ¹³C and ¹⁵N stable isotopes in OSCC tumor tissues reflect metabolic reprogramming associated with tumor progression and may correlate with cervical lymph node metastases. Methods: A prospective cohort of 61 patients with primary OSCC undergoing surgical treatment was analyzed. Tumor tissue samples were evaluated for the relative abundance of nitrogen-15 (¹⁵N) and carbon-13 (¹³C) isotopes using IRMS. Correlations between isotopic values and nodal metastases, as well as established clinicopathological risk factors, were assessed. Results: IRMS measurements of ¹³C and ¹⁵N abundance did not directly correlate with the presence of lymph node metastases but were associated with advanced tumor stages and negative prognostic features, such as angioinvasion/neuroinvasion. The median of the average nitrogen ¹⁵N content was higher in patients with more advanced clinical stages (11.89% in stage IV vs. 11.12% in stages I–III; p = 0.04‰), and the median δ¹³C was lower in stage IV compared to stages I–III (−22.40‰ vs. −22.88‰; p < 0.05). Patients with angioinvasion/neuroinvasion also had a lower median δ¹³C (−22.26‰ vs. −22.75‰; p < 0.05). These findings suggest that IRMS reflects metabolic changes in tumor biology rather than specifically predicting nodal metastases. Multivariate logistic regression identified age, gender, and clinical tumor stage as independent predictors of nodal involvement. Conclusion: IRMS-based isotopic profiling may reflect key metabolic alterations associated with OSCC progression. Although IRMS parameters of carbon ¹³C and nitrogen ¹⁵N were not independently predictive of lymph node status, they were associated with key adverse prognostic features, indicating their potential as adjunctive biomarkers that may complement traditional histopathological evaluation.

Background: Cervical lymph node metastases are a major prognostic factor in patients with oral squamous cell carcinoma (OSCC). Despite advances in imaging, accurate preoperative prediction of nodal involvement remains a challenge. This study evaluated the utility of Isotope Ratio Mass Spectrometry (IRMS) in assessing the risk of lymph node metastases in patients with OSCC. We hypothesize that alterations in the abundance of 13C and 15N stable isotopes in OSCC tumor tissues reflect metabolic reprogramming associated with tumor progression and may correlate with cervical lymph node metastases. Methods: A prospective cohort of 61 patients with primary OSCC undergoing surgical treatment was analyzed. Tumor tissue samples were evaluated for the relative abundance of nitrogen-15 (¹⁵N) and carbon-13 (¹³C) isotopes using IRMS. Correlations between isotopic values and nodal metastases, as well as established clinicopathological risk factors, were assessed. Results: IRMS measurements of ¹³C and ¹⁵N abundance did not directly correlate with the presence of lymph node metastases but were associated with advanced tumor stages and negative prognostic features, such as angioinvasion/neuroinvasion. The median of the average nitrogen ¹⁵N content was higher in patients with more advanced clinical stages (11.89% in stage IV vs. 11.12% in stages I–III; p=0.04), and the median δ¹³C was lower in stage IV compared to stages I–III (-22.40‰ vs. -22.88‰; p<0.05). Patients with angioinvasion/neuroinvasion also had a lower median δ¹³C (-22.26‰ vs. -22.75‰; p<0.05). These findings suggest that IRMS reflects metabolic changes in tumor biology rather than specifically predicting nodal metastases. Multivariate logistic regression identified age, gender, and clinical tumor stage as independent predictors of nodal involvement. Conclusion: IRMS-based isotopic profiling may reflect key metabolic alterations associated with OSCC progression. Although IRMS parameters of carbon 13C and nitrogen 15N were not independently predictive of lymph node status, they were associated with key adverse prognostic features, indicating potential as an adjunctive biomarker and may complement traditional histopathological evaluation.

Background/Objectives: Oral squamous cell carcinoma (OSCC) remains clinically heterogeneous, and prognosis is not always fully explained by conventional clinicopathological parameters. Systemic inflammation and tumor metabolic alterations may provide complementary information on tumor biology. This study aimed to assess associations between preoperative inflammatory markers, isotope ratio mass spectrometry (IRMS)-derived tumor signatures, clinicopathological features, and survival outcomes in OSCC. Methods: This exploratory retrospective secondary analysis included 50 consecutive patients with surgically treated, histologically confirmed OSCC. Preoperative blood-based markers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), white blood cell count, lymphocyte count, and C-reactive protein, were retrieved from routine laboratory tests. Matched tumor, surgical margin, and healthy oral mucosa samples were analyzed by IRMS for δ¹³C, δ¹⁵N, carbon and nitrogen content, and [N]/[C] ratio. Associations with clinicopathological variables, nodal status, overall survival (OS), and disease-free survival (DFS) were evaluated using non-parametric tests, Spearman correlations, and Cox regression models. Results: Tumor tissue showed a consistent isotope and elemental phenotype compared with healthy mucosa, including higher nitrogen content, lower carbon content, increased [N]/[C] ratio, lower δ¹⁵N, and less negative δ¹³C values. NLR, PLR, SII, and CRP were not robustly associated with standard clinicopathological features after correction for multiple testing. Correlations between inflammatory and isotope-derived parameters were modest. Higher NLR was associated with worse OS and DFS and remained significant after adjustment for pathologic nodal status. Less negative tumor δ¹³C showed a potential adverse prognostic signal. Conclusions: Systemic inflammatory markers and IRMS-derived tumor signatures appear to reflect partly distinct biological domains in OSCC. NLR may provide accessible prognostic information, while tumor δ¹³C warrants further validation as a metabolic biomarker.

Background/Objectives: Oral squamous cell carcinoma (OSCC) exhibits substantial biological heterogeneity, and current clinicopathological risk stratification incompletely reflects tumor metabolic behavior. Stable isotope ratio mass spectrometry enables quantitative assessment of carbon and nitrogen isotopic composition, potentially capturing cumulative metabolic reprogramming associated with tumor aggressiveness. This study evaluated whether isotopic signatures of tumor tissue and surgical margins are associated with lymph node metastasis and survival outcomes in OSCC. Methods: In this prospective study, 54 consecutive patients undergoing primary surgical treatment for OSCC were enrolled. Paired samples derived from tumor tissue and surgical margins were analyzed using isotope ratio mass spectrometry to determine the relative abundance of nitrogen-15 and carbon-13 isotopes. The primary endpoint was pathological lymph node metastasis. Secondary endpoints included disease-free survival and overall survival. Paired comparisons were performed using Wilcoxon signed-rank tests with false discovery rate correction. Logistic regression models for nodal metastasis were constructed using Firth penalization with bootstrap internal validation, while survival outcomes were evaluated using Cox proportional hazards models with model complexity restricted according to the number of events. Results: Tumor tissues demonstrated significantly lower δ¹³C and δ¹⁵N values and higher nitrogen-to-carbon ratios compared with surgical margins (all adjusted p < 0.05). In multivariable analysis, tumor δ¹⁵N was independently associated with lymph node metastasis and modestly improved model discrimination. However, it was not independently associated with disease-free or overall survival. Exploratory analyses indicated that higher δ¹³C values in surgical margins were independently associated with shorter disease-free survival. Conclusions: These findings suggest that isotope ratio mass spectrometry–based isotopic profiling identifies reproducible metabolic differences between tumor and margin tissues in OSCC. Tumor δ¹⁵N is associated with lymph node metastasis, whereas margin δ¹³C may reflect recurrence risk and potentially capture metabolic field effects. These findings are hypothesis-generating and warrant validation in larger, independent cohorts.

Background/Objectives: Oral squamous cell carcinoma (OSCC) remains clinically heterogeneous, and prognosis is not always fully explained by conventional clinicopathological parameters. Systemic inflammation and tumor metabolic alterations may provide complementary information on tumor biology. This study aimed to assess associations between preoperative inflammatory markers, isotope ratio mass spectrometry (IRMS)-derived tumor signatures, clinicopathological features, and survival outcomes in OSCC. Methods: This retrospective secondary analysis included 50 consecutive patients with surgically treated, histologically confirmed OSCC. Preoperative blood-based markers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), white blood cell count, lymphocyte count, and C-reactive protein, were retrieved from routine laboratory tests. Matched tumor, surgical margin, and healthy oral mucosa samples were analyzed by IRMS for δ¹³C, δ¹⁵N, carbon and nitrogen content, and [N]/[C] ratio. Associations with clinicopathological variables, nodal status, overall survival (OS), and disease-free survival (DFS) were evaluated using non-parametric tests, Spearman correlations, and Cox regression models. Results: Tumor tissue showed a consistent isotope and elemental phenotype compared with healthy mucosa, including higher nitrogen content, lower carbon content, increased [N]/[C] ratio, lower δ¹⁵N, and less negative δ¹³C values. NLR, PLR, SII, and CRP were not robustly associated with standard clinicopathological features after correction for multiple testing. Correlations between inflammatory and isotope-derived parameters were modest. Higher NLR was associated with worse OS and DFS and remained significant after adjustment for pathologic nodal status. Less negative tumor δ¹³C showed a potential adverse prognostic signal. Conclusions: Systemic inflammatory markers and IRMS-derived tumor signatures appear to reflect partly distinct biological domains in OSCC. NLR may provide accessible prognostic information, while tumor δ¹³C warrants further validation as a metabolic biomarker.