Prognostic implications of mucosal and deep margin distances according to T-status in oral tongue squamous cell carcinoma: A single-center retrospective study.

OBJECTIVE: To elucidate the prognostic implications of mucosal and deep margin distances in oral tongue squamous cell carcinoma (OTSCC), and to assess a different margin cut-off value in T1-T2 versus T3-T4 tumors. METHODS: This single-center retrospective study included 223 patients who received surgery for a primary OTSCC between January 2017 and December 2021. RESULTS: Multivariable analysis showed that deep margin distance ≥3 mm in T1-T2 tumors and ≥5 mm in T3-T4 tumors was significantly associated with better RFS and OS. Mucosal and deep margin distances were globally clinically useful for 2-year RFS prediction of T1-T2 tumors, for which deep margins seemed to have more clinical utility than mucosal margins. The influence of margin distances on 2-year RFS seemed greater for T1-T2 tumors than T3-T4 tumors. CONCLUSION: Mucosal and deep margin distances were associated with OS and RFS in OTSCC. Shorter deep margin distances may be aimed for in T1-T2 versus T3-T4 tumors.

Mutation analysis in individual circulating tumor cells depicts intratumor heterogeneity in melanoma.

Circulating tumor DNA (ctDNA) is the cornerstone of liquid biopsy diagnostics, revealing clinically relevant genomic aberrations from blood of cancer patients. Genomic analysis of single circulating tumor cells (CTCs) could provide additional insights into intra-patient heterogeneity, but it requires whole-genome amplification (WGA) of DNA, which might introduce bias. Here, we describe a novel approach based on mass spectrometry for mutation detection from individual CTCs not requiring WGA and complex bioinformatics pipelines. After establishment of our protocol on tumor cell line-derived single cells, it was validated on CTCs of 33 metastatic melanoma patients and the mutations were compared to those obtained from tumor tissue and ctDNA. Although concordance with tumor tissue was superior for ctDNA over CTC analysis, a larger number of mutations were found within CTCs compared to ctDNA (p = 0.039), including mutations in melanoma driver genes, or those associated with resistance to therapy or metastasis. Thus, our results demonstrate proof-of-principle data that CTC analysis can provide clinically relevant genomic information that is not redundant to tumor tissue or ctDNA analysis.