The 8th TNM classification for oral squamous cell carcinoma: What is gained, what is lost, and what is missing

Abstract

The 8th TNM edition remarkably changed the classification of T and N categories for oral squamous cell carcinoma (OSCC). The present study aims at evaluating the improvement in prognostic power compared to the 7th edition, pros and cons of the modifications, and parameters deserving consideration for further implementations. Materials and methods: All OSCCs treated with upfront surgery at our institution between 2002 and 2017 were included. Demographics, clinical-pathological and treatment variables were retrieved. All tumors were classified according to both the 7th and 8th TNM edition, and patients were grouped according to the shift in T category and stage. Survivals were calculated with the Kaplan-Meier method. Univariate and multivariate analysis were carried out. Receiver Operating Characteristics (ROC) curve analyses were performed to find the best cut-off of DOI (in patients with DOI > 10 mm) and number of involved nodes (in positive neck patients). Results: 244 patients were included. T, N categories, and stage changed in 59.2%, 20.5%, and 49.1% patients, respectively; 41.5% of patients were upstaged. The new T classification well depicted prognosis according to OS. Five-year overall (OS), disease-specific, recurrence-free (RFS) survivals were 60.5%, 70.9%, 59.8%, respectively. According to ROC curves, DOI > 20 mm and 4 positive nodes were the best cutoffs for OS and RFS. Conclusion:The novelties introduced in 8th TNM edition were positive. DOI > 20 mm for T4 definition and number of positive nodes (0, < 4, 4 or more) for N classification emerged as the most urgent factors to be implemented.

Comparison of Different Staging Systems Applied to a Cohort of Patients With Oral Tongue and Floor of the Mouth Cancer

“…However, only patients with a high metastatic nodal count, namely those included in the N3a and N3b categories, showed a significantly worse prognosis. This is in line with other reports which demonstrated that the negative prognostic impact of a high number of positive nodes can also outweigh the detrimental effect of ENE [ 19 ]. While the TNM pN lacked in prognostic stratification, the pN-N+ classification succeeded in creating a clear distinction at least between patients with low- and high-nodal disease burden, namely between N2 and N3a categories, while the difference between N1 and N2, and between N3a and N3b, was not significant.…”

“…In line with previous classifications, the major emphasis was put on lymph nodes laterality and size, while nodes numerosity was still overlooked. However, increasing evidence shows that the absolute count of metastatic lymph nodes strongly predicts cancer mortality [17][18][19]. Therefore, an alternative nodal classification (called pN-N+ classification), based on lymph nodes numerosity and ENE, was developed and tested, demonstrating good prognostication capability [17,20,21].…”

Editorial: Oral Oncology: From Precise Surgery to Precision Medicine and Surgery

“…A comparison with the former 7th TNM (7TNM) version, points to the existence of a number of differences with a valuable impact on the choice of treatment. This interesting study consolidates the conclusions of others [ 5 , 6 ], by suggesting that 8TNM provides a better estimation of the risk of T3 OSCC, a T category virtually non-existent in the 7TNM. The authors, following a previous paper from Mirian et al [ 7 ], suggest how tumor staging could be improved by closer monitoring of the number of metastatic lymph nodes, among other parameters.…”

Current Aspects of Oral Squamous Cell Carcinoma in Pakistan: A Review

“…Explicit portrayal is the key for the choice of a right technique for treatment, the conceivable result and restriction for certain activities. [16][17]…”