Is There an Interplay between Oral Microbiome, Head and Neck Carcinoma and Radiation-Induced Oral Mucositis?

Head and neck carcinoma is one of the most common human malignancy types and it ranks as the sixth most common cancer worldwide. Nowadays, a great potential of microbiome research is observed in oncology—investigating the effect of oral microbiome in oncogenesis, occurrence of treatment side effects and response to anticancer therapies. The microbiome is a unique collection of microorganisms and their genetic material, interactions and products residing within the mucous membranes. The aim of this paper is to summarize current research on the oral microbiome and its impact on the development of head and neck cancer and radiation-induced oral mucositis. Human microbiome might determine an oncogenic effect by, among other things, inducing chronic inflammatory response, instigating cellular antiapoptotic signals, modulation of anticancer immunity or influencing xenobiotic metabolism. Influence of oral microbiome on radiation-induced oral mucositis is expressed by the production of additional inflammatory cytokines and facilitates progression and aggravation of mucositis. Exacerbated acute radiation reaction and bacterial superinfections lead to the deterioration of the patient’s condition and worsening of the quality of life. Simultaneously, positive effects of probiotics on the course of radiation-induced oral mucositis have been observed. Understanding the impact on the emerging acute radiation reaction on the composition of the microflora can be helpful in developing a multifactorial model to forecast the course of radiation-induced oral mucositis. Investigating these processes will allow us to create optimized and personalized preventive measures and treatment aimed at their formation mechanism. Further studies are needed to better establish the structure of the oral microbiome as well as the dynamics of its changes before and after therapy. It will help to expand the understanding of the biological function of commensal and pathogenic oral microbiota in HNC carcinogenesis and the development of radiation-induced oral mucositis.

The potential role of imaging techniques in avoiding neck dissection during salvage surgery after head and neck carcinoma treated with bioradiotherapy

ObjectiveThis study aimed to evaluate the effectiveness of computed tomography and positron emission tomography-computed tomography prior to salvage surgery after head and neck carcinoma treated with bioradiotherapy and to look at the role of neck dissection in this setting.MethodThis study was a retrospective chart review of a series of consecutive patients with locally advanced head and neck squamous cell carcinoma treated with bioradiotherapy. Radiological and pathological stages were compared to evaluate the accuracy of computed tomography and positron emission tomography-computed tomography in detecting occult neck metastasis in the context of recurrence of primary tumour. In order to assess the impact of neck dissection on survival, Kaplan–Meier survival curves after salvage surgery with and without neck dissection were derived.ResultsA total of 268 patients were identified, of which 22 underwent salvage surgery. The negative predictive value of computed tomography and positron emission tomography-computed tomography was excellent. Neck dissection did not represent an improvement on overall, disease specific and regional recurrence free survival (p = 0.67, p = 0.91 and p = 0.62, respectively) amongst clinically and radiologically negative necks.ConclusionConservative treatment of the neck should be considered when dealing with patients with primary site recurrence or persistent disease after bioradiotherapy without evidence of neck disease.

The Effectiveness and Safety of Metronomic Chemotherapy in Patients with Head and Neck Carcinoma: A Systematic Review and Meta-analysis

Background: Head and neck carcinoma, usually begins in the squamous cells, not only seriously endangers the quality of life, but brings a heavy financial burden for families and countries. Metronomic chemotherapy, a frequent administration of chemotherapeutic agents at a non-toxic dose, gives an alternative low-cost and tolerated approach for patients. We conducted a systematic review to find the effectiveness and safety of metronomic chemotherapy for head and neck cancer.Methods: We searched seven databases and Clinical.gov from the inception to July 14, 2021. The patients diagnosed head and neck cancer and older than 18 were included. Metronomic chemotherapy was defined as intervention. Randomized and non-randomized trials were all included. Quality assessment of included randomized control trials was performed using the Cochrane Risk-of-Bias criteria, cohort studies using The Newcastle-Ottawa Scale (NOS), single arm trials using the checklist recommended by The Agency for Healthcare Research and Quality (AHRQ). Studies were synthetized using a narrative approach. The indicators used for meta-analysis was hazard ratio (HR).Results: 310 Literatures were potentially eligible from 7 databases, finally 13 records were included. Five studies were of high quality, while eight were of moderate quality. The overall effect of HR for death of five trials reported had no statistically significant (HR=0.89, 95%CI 0.71-1.10). Subgroup analysis by different design showed a statistically significant HR (0.73, 95%CI 0.60-0.90) in randomized control trials while no significant difference in subgroup of prospective study design (HR=1.23, 95%CI 0.72-2.10). As for HR for PFS, there was no significant difference in overall effect of four studies. HR for PFS was 0.84 (95%CI 0.55-1.31). Subgroup analysis of study design showed that randomized control trials produced a significant HR (0.54, 95%CI 0.45-0.64), while prospective studies did not (1.25, 95%CI 0.73, 2.14).Conclusions: Metronomic chemotherapy has been an optimistic option for treatment for advanced head and neck cancer, especially in low income and medical resource-restricted regions.