Reframing Histological Risk Assessment of Oral Squamous Cell Carcinoma in the Era of UICC 8th Edition TNM Staging

Abstract

Objectives To assess whether application of the risk model originally proposed by Brandwein-Gensler, influences survival and disease progression in patients treated for oral squamous cell carcinoma (OSCCs) Materials and Methods Tumours from 134 T1 and T2 OSCC resections (7th edition) were scored independently by 3 histopathologists according to worst pattern of invasion (WPOI), lymphocytic host response (LHR) and perineural invasion (PNI) and categorised according to risk score. Local recurrence, locoregional recurrence, disease progression and overall survival were study endpoints. Interobserver variability of pathologist scoring was also assessed. Results Seventy-two patients (54%) were classified with low or intermediate risk and 62 (46%) patients were ‘high risk’. The inter-observer agreement was in moderate to strong agreement with the consensus scores (k range = 0.45–0.82). There was statistical significance between distant metastasis and ‘high risk’ tumours. Thirty tumours were upstaged to T3 in the 8th edition TNM staging, of which 83% had high risk scores. Overall risk score and TNM8 T stage has significant correlation with overall survival in comparison to the TNM 7 T stage. Conclusion ‘High risk’ tumours were significantly associated with distant metastasis possibly due to the greater likelihood of aggressive features such as WPOI and PNI. Primary tumours are more likely to express high risk features with increasing T stage. None of the patients classified as ‘low risk’ died perhaps suggesting these tumours represent a rare variant of OSCC with excellent prognosis.

Evaluation of Histopathological Risk Model in a Cohort of Oral Squamous Cell Carcinoma Patients Treated with Accompanying Neck Dissection

“…As stated above, none of the tumours with a risk score of zero showed evidence of metastasis in the accompanying neck dissection (NPV = 100%) perhaps indicating the metastatic potential of these tumours is low. This correlates with our previous observation that low risk tumours showed excellent overall survival with none of the low patients in our original series dying of disease or showing evidence of disease progression after treatment [8]. These findings should be interpreted with a degree caution as low risk cases made up just 4.7% of the cases in the current series (n = 4) and 6% (n = 8/134) of the original series.…”

“…Adding to the sizable body of evidence linking histological risk assessment with clinical outcomes [1,8,[11][12][13][14], we were able to demonstrate statistically significant associations with overall risk score its individual parameters (WPOI, PNI & LHR) with the presence of nodal metastasis in accompanying neck dissection specimens. PNI was significantly associated with the presence of ECS however there was no such association with overall risk score, WPOI or LHR.…”

“…The survival probability by 3 years was similar: 33% and 36% respectively. In a previous study we found an association with high risk score and PNI so could the risk score be used in turn to predict the possibility of ECS [ 8 ]. In comparison to older staging systems, the presence of extracapsular spread in a neck dissection for oral squamous cell carcinoma significantly upstages the N stage in the TNM8 [ 9 ] such is its prognostic influence.…”

“…Our recent series of 134 patients with early stage oral cancer, our group showed significant association between risk score, overall survival and distant metastasis. Furthermore we were able to demonstrate that tumours upstaged to T3 on TNM8 criteria were more likely to demonstrate high risk score [ 8 ]. Within the study population, 85/134 patients underwent a neck dissection along with excision of the primary tumour.…”

Development and Validation of Prognostic Models for Oral Squamous Cell Carcinoma: A Systematic Review and Appraisal of the Literature

“…Nowadays, the Tumor-Node-Metastasis (TNM) staging system is employed worldwide to predict tumor prognosis and to guide physicians towards the correct treatment choice, however, survival outcomes in patients classified within the same TNM stage class could be dramatically different, with discrepancies in therapy response and tumor management [ 5 ].…”