Clinicopathological features, management and outcome of patients with poorly-differentiated oral and oropharyngeal squamous cell carcinoma

Abstract

Background

The purpose of this study was to explore the clinicopathological features, risk factors, and management of poorly differentiated oral and oropharyngeal squamous cell carcinoma (OOSCC) patients in the northern Chinese population.

Method

A total of 118 poorly differentiated OOSCC patients from 2236 consecutive cases were retrospectively enrolled in this study.

Results

Cox regression analysis showed that site (hazard ratio (HR): 2.561, 95% confidence interval (CI): 1.064–6.164, p = 0.036) and lymph node ratio (LNR) (HR: 3.915, 95% CI: 1.797–8.530, p = 0.001) were independent predictive factors for 5-year disease-specific survival (DSS). LNR >0.036, oropharynx site, and advanced clinical stage formulate a model of risk stratification. The patients with a risk score of ≥2 were identified as the high-risk population, and patients with a risk score of 0 or 1 were identified as the low-risk population. Patients in the high-risk population who underwent surgery plus concurrent chemoradiotherapy (CCRT) had markedly better 5-year DSS than those who only underwent surgery (60.0% vs. 20.0%, p = 0.016). However, patients in the low-risk population who underwent surgery alone exhibited a similar 5-year DSS (68.2%) compared with those who received surgery plus radiotherapy (RT) (68.2%) or surgery plus CCRT (50.0%) (p = 0.907).

Conclusions

High LNR, oropharynx site and advanced clinical stage constitute a model of risk stratification for patients with poorly differentiated OOSCC. If two or more risk factors are present, surgery and adjuvant chemoradiotherapy can give the best prognosis.

Introduction

Poorly differentiated disease is a rare pathological type that accounts for approximately 5% of all patients with oral and oropharyngeal squamous cell carcinoma (Feng et al., 2015, Feng et al., 2016b, Feng et al., 2017). Accumulating evidence has shown that poor differentiation of oral and oropharyngeal squamous cell carcinoma is significantly associated with more aggressive clinicopathological features, for example, lymph node metastasis and extracapsular spread (ECS) of the primary tumor, and a higher risk of developing local and/or regional recurrence and/or distant metastases after primary treatment (Liao et al., 2008, Liao et al., 2007). Therefore, poorly differentiated OOSCC patients were believed to have a worse prognosis than those with moderately and well-differentiated diseases (Brandwein-Gensler et al., 2005, Kang et al., 2011b).

Our recent study found that the degree of differentiation was the decisive factor in long-term survival for patients suffering from multiple synchronous primary cancers involving oral and oropharyngeal subsites (Feng et al., 2016b). However, we also made the interesting observation in our clinical practice that poor differentiation was not often an independent prognostic factor for selected oral and oropharyngeal squamous cell carcinoma (Feng et al., 2015, Niu et al., 2014). The above results have shown that the value of histological classifications is variable across different OOSCC populations. Because poorly differentiated OOSCC is relatively uncommon, its clinicopathological features, risk stratification, and principles of management still lack evidence from large-sample clinical studies, especially for the northern Chinese population. This low incidence rate made it very difficult to perform prospective, evidence-based studies for these particular tumors.

The purpose of this retrospective study was to explore the clinicopathological features of patients with poorly differentiated OOSCC in the Northern Chinese population (immunohistochemistry (IHC) of p16 protein and in situ hybridization (ISH) of HPV 16/18-specific DNA for oropharyngeal cancers were detected). In addition, we aimed to sort the risk classification of these OOSCC patients into high- and low-risk populations to aid surgeons in adopting a more strategic treatment policy in the future.