It has been 24 years since rapamycin (sirolimus) was approved to mitigate solid organ transplant rejection and 16 years since mTOR (mammalian/mechanistic target of rapamycin) inhibitors reached patients as a cancer therapy. While the clinical benefits of mTOR inhibitors (mTORi) are robust, so too are their toxicities. Among the most common issues is the development of ulcers of the oral mucosa (mTOR-inhibitor associated stomatitis; mIAS). These lesions are distinct from those of other anti-cancer agents, occur with regularity, and impact patient outcomes. mIAS pathogenesis has been the subject of speculation, and its similar presentation to recurrent aphthous stomatitis (RAS) has led to the hypothesis that it might serve as a surrogate to better understand RAS. Based on a review of the literature, the current manuscript provides a hypothesis regarding the mechanisms by which mTORis uniquely initiate mucosal injury and an explanation for the observation that steroids (also an immunosuppressive) are effective in its treatment through a non-immunologic mechanism. Unexplained unique features of mIAS are discussed in this review in the context of future investigation.

Introduction

The negative consequences of healthcare-associated infections (HAI) on the burden of illness (BOI) of cancer patients are well-established. However, there is a paucity of research on HAI among cancers of the lip, oral cavity and pharynx (CLOCP), and whether HAI-related BOI differed for other common solid tumors-malignant neoplasm of the colon (MNC) and malignant neoplasm of the lung (MNL).

Methods

We utilized the United States' National Inpatient Sample database 2017 to study longitudinal inpatient hospital stay of CLOCP, MNC and MNL. Patient demographics and hospital characteristics of patients were assessed, and the impact of HAI-related BOI compared based on differences in length of hospital stays (LOS), total charges during hospitalization and mortality were compared.

Findings

In 2017, of the 54,934 patients with CLOCP, 1.2% had HAI, compared to MNC (n=64,470) with 2% HAI and MNL (n=154,685) with 1.2% HAI. In adjusted multivariable regression analysis, we determined CLOCP patients with HAI had LOS of 5.6 days longer (95% CIs, 3.0-8.2 days, P < 0.001), and hospitalization charges of $40,341 higher (95%CIs 15,715-64,967, P < 0.01) than the non-HAI CLOCP patients. Mortality was not significantly different among HAI and non-HAI CLOCP patients (odds ratio: 0.80; 95%CIs 0.35-1.87, P = 0.6). In unadjusted analysis, LOS and total charges were higher for CLOCP-HAI patients vs. MNC-HAI or MNL-HAI patients.

Conclusion

HAI in patients with CLOCP patients were associated with an increased BOI, and this is considerably higher than observed in patients with MNC or MNL patients who had HAI.

OBJECTIVES: Immune-related adverse events (irAEs) are common. Oral irAEs tend to cluster in patients who experience concurrent toxicities. We aimed to characterize the frequency and trajectory of non-oral irAEs in patients who developed oral irAEs, assess their relationship with non-oral irAEs, and compare those characteristics with patients without oral irAEs. METHODS: A retrospective chart review was conducted to identify patients who started ICIT between December 11, 2011, and September 15, 2019 (n = 4683) in the Mass General Brigham Registered Patient Data Registry. Demographic information, cancer diagnosis, ICIT regimen, treatment duration, and time and number of infusions to irAE onset were recorded. Non-oral irAEs were categorized into 13 groups. Patients with melanoma, pulmonary cancer, or head and neck cancer who had oral irAEs were then matched with those without oral irAEs to compare the prevalence of concomitant non-oral irAEs. RESULTS: Three hundred and fourteen patients with oral irAEs with a mean age of 65.9 ± 12.6 years (43.3% females) were included. Patients with multiple oral irAEs were more likely to have non-oral irAEs (OR: 2.7, 95% CI, 1.3-3.5), including cutaneous (OR: 1.7, 95% CI, 1.1-3.0), rheumatological (OR: 2.2, 95% CI, 1.1-4.2), thyroid (OR: 2.4, 95% CI, 1.2-4.9), and neurological irAEs (OR: 2.5, 95% CI, 1.0-6.3). Compared to matched patients with non-oral irAEs, patients with oral irAEs were more likely to have cutaneous (OR: 1.7, 95% CI, 1.0-2.8) and thyroid (OR: 2.86, 95% CI, 1.1-7.5) irAEs. The development of oral and non-oral irAEs is often coincidental. CONCLUSION: Patients who have non-oral irAEs should be monitored for development of oral irAEs for prompt management.

The incidence of oropharyngeal cancer (OPC) has been rising, especially among middle-aged men. While Human Papillomavirus (HPV) has been irrevocably implicated in the pathogenesis of oropharyngeal cancer (OPC), the current HPV vaccination uptake rate remains low in the US. The aim of our study was to evaluate the impact of increased HPV vaccination coverage on HPV-associated OPC incidence and costs. A decision analytic model was constructed for hypothetical cohorts of 9-year-old boys and girls. Two strategies were compared: 1) Maintaining the current vaccination uptake rates; 2) Increasing HPV vaccination uptake rates to the Healthy People 2030 target (80%) for both sexes. Increasing HPV vaccination coverage rates to 80% would be expected to prevent 5,339 OPC cases at a cost of $0.57 billion USD. Increased HPV vaccination coverage would result in 7,430 quality-adjusted life year (QALY) gains in the overall population, and it is estimated to be cost-effective for males with an incremental cost-effectiveness ratio of $86,940 per QALY gained under certain conditions. Expanding HPV vaccination rates would likely provide a cost-effective way to reduce the OPC incidence, particularly among males.

We have characterized a novel 21 amino acid-peptide derived from Antrum Mucosal Protein (AMP)-18 that mediates growth promotion of cultured normal epithelial cells and mitigates radiation-induced oral mucositis in animal models, while suppressing in vitro function of cancer cells. The objective of this study was to evaluate these dual potential therapeutic effects of AMP peptide in a clinically relevant animal model of head and neck cancer (HNC) by simultaneously assessing its effect on tumor growth and radiation-induced oral mucositis in an orthotopic model of HNC. Bioluminescent SCC-25 HNC cells were injected into the anterior tongue and tumors that formed were then subjected to focal radiation treatment. Tumor size was assessed using an in vivo imaging system, and the extent of oral mucositis was compared between animals treated with AMP peptide or vehicle (controls). Synergism between AMP peptide and radiation therapy was suggested by the finding that tumors in the AMP peptide/radiation therapy cohort demonstrated inhibited growth vs. radiation therapy-only treated tumors, while AMP peptide-treatment delayed the onset and reduced the severity of radiation therapy-induced oral mucositis. A differential effect on apoptosis appears to be one mechanism by which AMP-18 can stimulate growth and repair of injured mucosal epithelial cells while inhibiting proliferation of HNC cells. RNA microarray analysis identified pathways that are differentially targeted by AMP-18 in HNC vs. nontransformed cells. These observations confirm the notion that normal cells and tumor cells may respond differently to common biological stimuli, and that leveraging this finding in the case of AMP-18 may provide a clinically relevant opportunity.

Immune checkpoint inhibitors (ICIs) are a revolutionary class of antineoplastic therapy that restore anti-tumor immunity. Consequences of this enhanced immune response include a multitude of immune related adverse events (irAEs) that can affect any body system, including the mouth. Orofacial irAEs reproduce features of numerous immune-mediated conditions, including oral lichen planus, mucous membrane pemphigoid, and Sjögren syndrome, among others. The aim of this review is to summarize known orofacial irAEs and to familiarize oral healthcare providers with how to identify and manage these toxicities as part of the care team for patients treated with ICIs.