Background/Objectives: The oral microbiome has been implicated in the pathogenesis of head and neck squamous cell carcinoma (HNSCC). This review examines the association between specific oral bacterial taxa and HNSCC. Methods: A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to examine the relationship between the oral microbiome and HNSCC. A comprehensive literature search was conducted in databases including EMBASE, Cochrane Library, Web of Science, Medline, and PubMed. Results: Following the screening of 284 articles, 21 studies met the inclusion criteria, comprising 1023 HNSCC patients (male: n = 806, 79%; female: n = 217, 21%) and 837 healthy controls (male: n = 622, 74%; female: n = 215, 25.7%). Although findings on alpha diversity were inconsistent, a significant difference in beta diversity was consistently reported between HNSCC patients and healthy controls. HNSCC patients exhibited higher relative abundances of Firmicutes and Synergistetes at the phylum level; Fusobacterium, Prevotella, Porphyromonas, Parvimonas, and Peptostreptococcus at the genus level; and Fusobacterium nucleatum, Prevotella intermedia, Lactobacillus spp., and Porphyromonas gingivalis at the species level. In contrast, healthy controls showed higher abundances of Proteobacteria and Actinobacteria at the phylum level; Streptococcus, Actinomyces, Corynebacterium, Rothia, and Veillonella at the genus level; and Haemophilus influenzae, Rothia mucilaginosa, and Streptococcus mitis at the species level in most studies. Conclusions: The findings indicate distinct alterations in oral microbiome diversity and composition among HNSCC patients, highlighting the role of microbial dysbiosis in cancer progression. Standardized protocols for oral sample collection and microbiota analysis are essential to facilitate more robust, comparable, and clinically meaningful research outcomes.

Introduction: Long term survival for adenoid cystic carcinoma (ACC) arising from the head and neck declines for many decades after initial treatment due to late disease relapse. Follow up and surveillance imaging practices vary due to limited evidence as well as a lack of international guidelines (until 2021).Methods: A retrospective cohort study was conducted for patients treated curatively for ACC between 2007 and 2024 at a single institution. Clinicopathologic information, treatment details, patterns of follow‐up (including radiologic investigations) and oncological outcomes are reported.Results: 51 patients comprised the study cohort. Median age was 50 years; 96% of patients underwent surgery and adjuvant radiation therapy. Median follow‐up was 7.65 years. 5‐year overall survival (OS) and disease‐free survival (DFS) were 88% and 73% respectively. 18% and 61% of patients underwent surveillance imaging within 3‐ and 12‐months of treatment completion respectively. 80% of first recurrences were detected on surveillance imaging. Half the episodes of first disease recurrence occurred within 5 years of initial treatment, a further 25% within 10 years and the remaining 25% occurred > 10 years post treatment.Conclusion: This cohort of patients curatively treated for ACC at a single institution highlights the propensity for late distant relapse as well as heterogeneity of surveillance imaging. A local institutional protocol is proposed based upon the 2021 ASCO guidelines to standardise clinical and radiologic follow‐up for this group.

Background: A significant minority of patients in high income countries with symptomatic mucosal head and neck squamous cell carcinomas (HNSCC) warrant treatment of their locoregional disease but are not suitable for standard high dose radiation therapy (RT) with or without concurrent chemotherapy. This study aimed to determine the factors associated with locoregional control (LRC) and survival for patients undergoing high dose palliative-intent RT, to help improve patient selection for this treatment approach. Materials and methods: This retrospective cohort study included all patients with HNSCC who received high dose RT (50–55 Gy in 20 fractions over 4 weeks) with palliative-intent from 2007–2023 at an academic Australian cancer centre. Results: 53 patients comprised the study cohort, of which 92% completed the prescribed RT in full. Median overall survival was 21.6 months and in-field LRC at 12-months was 80%. Acute toxicities were low [Common Terminology Criteria for Adverse Events (CTCAE) grade 3 mucositis 17%, local pain 6.5%, and dysphagia 4.4%, with no grade 4–5 toxicities], with resolution of majority by six months post RT (7% grade 2, no grade 3 or higher toxicities). Larger primary tumours (T3 or T4) and more advanced stage disease [American Joint Committee on Cancer (AJCC) stage III–IV, 8^th edition] were associated with worse in-field LRC. Conclusions: High dose palliative-RT in patients with mucosal HNSCC not suitable for definitive chemoradiotherapy provided durable local control with low toxicities after 12 months. In-field locoregional failures were more likely for more advanced disease. Keywords: head and neck cancer radiation therapy hypofractionation palliative care

Background: Surgical resection is the mainstay of curative treatment for localised salivary gland malignancies of the head and neck, with adjuvant radiation therapy (RT) indicated in the presence of high-risk features to reduce the risk of recurrence. Most patients survive for many decades after locoregional treatment and thus understanding the impact of treatment(s), particularly RT, on long term quality of life (QOL) is critical. This study aimed to investigate the long-term QOL of patients treated with surgery and adjuvant RT for primary salivary gland malignancies of the head and neck, and to assess for potential predictors of QOL which might guide refinement of current treatments and improve survivorship care. Methods: This retrospective cohort study included patients who underwent surgery and post-operative RT for primary malignant salivary gland tumours of the head and neck at a single tertiary cancer centre between 2006 and 2022. Patient, tumour and treatment information was extracted from a prospectively maintained database. Patients who were still alive were contacted to complete a QOL survey. Kaplan-Meier survival analysis was used to summarise overall survival (OS) and disease-free survival (DFS), with log-rank test used to assess prognostic factors. Univariate binary logistic regression model was used to identify factors associated with worse QOL. Results: Sixty-seven patients underwent surgery and RT during the study period. Median follow up was 4.4 years [interquartile range (IQR), 2.4–7.4 years] for all patients and 5.2 years (IQR, 3.9–9.2 years) for patients who completed the QOL survey 5-year OS and DFS and local failure rates were 79%, 79% and 3% respectively (all patients). Twenty-nine patients completed the QOL survey, of which 93% were in remission. Most patients (79%) reported their health as the same or better than before RT. Almost all patients (90%) had no treatment regret regarding receipt of adjuvant RT. Conclusions: Surgery and adjuvant RT achieves durable local control, excellent patient reported QOL and low levels of treatment regret in patients with high-risk primary salivary gland malignancies. However, survivorship care remains a key issue in patents with potentially lengthy survival. Future prospective studies may identify novel biomarkers to further refine patient selection for adjuvant RT, while longitudinal QOL assessment will assist in further refining survivorship protocols.