The broadening scope of oral mucositis and oral ulcerative mucosal toxicities of anticancer therapies.

Oral mucositis (OM) is a common, highly symptomatic complication of cancer therapy that affects patients' function, quality of life, and ability to tolerate treatment. In certain patients with cancer, OM is associated with increased mortality. Research on the management of OM is ongoing. Oral mucosal toxicities are also reported in targeted and immune checkpoint inhibitor therapies. The objective of this article is to present current knowledge about the epidemiology, pathogenesis, assessment, risk prediction, and current and developing intervention strategies for OM and other ulcerative mucosal toxicities caused by both conventional and evolving forms of cancer therapy.

Comparisons of Non-Oral Immune-Related Adverse Events Among Patients With Cancer With Different Oral Toxicity Profiles.

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 ±â€…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.

Comparisons of successful and failed Phase III trials of drugs and biologicals tested for mitigation of oral mucositis in patients being treated with radiotherapy with or without concomitant chemotherapy for cancers of the head and neck.

Oral mucositis (OM) remains a significant toxicity among patients being treated with radiotherapy (RT) alone or with concomitant chemotherapy (CRT) for cancers of the head and neck (HNC). Given its clinical significance as an unmet need and its potential commercial viability, the pharmaceutical industry has been actively pursuing an effective intervention. Despite this interest and activity, only a few agents have been studied in Phase III trials (n = 6). The objective of this study was to identify common features that differentiate successful and failed Phase III OM trials. We used the United States Patent and Trademark Office Patent Public Search database to search patents with "oral mucositis" in the claims. We then searched ClinicalTrials.gov and PubMed to determine if Phase III or Phase II trial data for identified biologics/drugs had been published. We assessed each Phase III and Phase II trial for characteristics that may be associated with trial success or failure. We considered a study as a "success" if the primary endpoint reached statistical significance, and we considered a study as "failure" if the primary endpoint did not reach statistical significance. Of the three successful Phase III trials, one investigated avasopasem manganese (Galera Therapeutics) and two examined palifermin (Amgen). The three failed trials included those evaluating dusquetide (Soligenix), iseganan hydrochloride (IntraBiotics Pharmaceuticals), and clonidine (Monopar Therapeutics). We found that differences in the level of sponsor funding, patient inclusion criteria including radiation source and concomitant chemotherapy regimen, and concordance of primary efficacy outcomes between Phase II and Phase III trials influenced outcomes. To properly design clinical trials for OM in HNC patients, it is important that researchers and sponsors take note of specific study characteristics associated with success or failure, particularly with Phase III trials where the risks and costs are the highest.

Application of big data analyses to compare the impact of oral and gastrointestinal mucositis on risks and outcomes of febrile neutropenia and septicemia among patients hospitalized for the treatment of leukemia or multiple myeloma.

PURPOSE: Oral ulcerative mucositis (UM) and gastrointestinal mucositis (GIM) have been associated with increased likelihood of systemic infection (bacteremia and sepsis) in patients being treated for hematological malignancies. To better define and contrast differences between UM and GIM, we utilized the United States 2017 National Inpatient Sample and analyzed patients hospitalized for the treatment of multiple myeloma (MM) or leukemia. METHODS: We utilized generalized linear models to assess the association between adverse events-UM and GIM-among hospitalized MM or leukemia patients and the outcome of febrile neutropenia (FN), septicemia, burden of illness, and mortality. RESULTS: Of 71,780 hospitalized leukemia patients, 1255 had UM and 100 GIM. Of 113,915 MM patients, 1065 manifested UM and 230 had GIM. In an adjusted analysis, UM was significantly associated with increased risk of FN in both the leukemia (aOR = 2.87, 95% CI = 2.09-3.92) and MM cohorts (aOR = 4.96, 95% CI = 3.22-7.66). Contrastingly, UM had no effect on the risk of septicemia in either group. Likewise, GIM significantly increased the odds of FN in both leukemia (aOR = 2.81, 95% CI = 1.35-5.88) and MM (aOR = 3.75, 95% CI = 1.51-9.31) patients. Similar findings were noted when we restricted our analysis to recipients of high-dose condition regimens in preparation for hematopoietic stem-cell transplant. UM and GIM were consistently associated with higher burden of illness in all the cohorts. CONCLUSION: This first use of big data provided an effective platform to assess the risks, outcomes, and cost of care of cancer treatment-related toxicities in patients hospitalized for the management of hematologic malignancies.

Oral side effects of immune checkpoint inhibitor therapy (ICIT): An analysis of 4683 patients receiving ICIT for malignancies at Massachusetts General Hospital, Brigham & Women's Hospital, and the Dana-Farber Cancer Institute, 2011 to 2019.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are increasingly accepted as a treatment option for several cancers. Although various systemic immune-related adverse events (irAEs) have been characterized, the effect of ICIs on the oral cavity and contiguous structures is still poorly understood. METHODS: Electronic medical records of 4683 patients in the Mass General Brigham Registered Patient Data Registry who received ICI therapy (ICIT) between December 2011 and September 2019 were reviewed. Reports of oral conditions were categorized into oral mucosal disorders, xerostomia, and dysgeusia. After applying exclusion criteria, demographic characteristics and clinical features were summarized for the patients who had oral irAEs. RESULTS: In total, 317 patients developed oral conditions that were associated with ICIT (incidence, 6.8%; 317 of 4683 patients). These conditions included xerostomia (68.5%), oral mucosal disorders (33.4%), and dysgeusia (24.0%). In patients with oral irAEs, respiratory cancer (28.4%) was the most common primary cancer, followed by melanoma (26.2%), and head and neck cancer (14.8%). Oral mucosal disorders developed after the initiation of ICIT between 2 and 851 days (between 1 and 1332 days in patients with xerostomia and between 1 and 1455 days in patients with dysgeusia). Of all oral irAEs, 50.9% developed within 3 months, and 85.5% developed within 12 months. CONCLUSIONS: Oral side effects appear to be more common among patients who receive ICIT than has been previously reported. Concomitant cytotoxic regimens may exacerbate the risk of oral adverse events, perhaps representing the sum of the effects of different, but simultaneous or sequential, pathogenic mechanisms. Additional studies are warranted to better characterize oral irAEs and their biologic basis.

Treatment for Oral Mucositis-Current Options and an Update of Small Molecules Under Development.

OPINION STATEMENT: Despite its history as one of the most impactful toxicities associated with cytotoxic cancer therapy, oral mucositis (OM) remains an unmet clinical need which affects hundreds of thousands of patients. Descriptions of its complex pathogenesis have provided mechanistic targets which are being exploited to develop an effective therapeutic intervention. Favorable results of recently completed clinical trials in which agents focused on interrupting the early stages of the mucositis biological cascade were assessed provide reason for optimism, not only for oral mucositis but also for halo indications which share its pathobiogenesis.

A hypothesis for the pathogenesis of radiation-induced oral mucositis: when biological challenges exceed physiologic protective mechanisms. Implications for pharmacological prevention and treatment.

Oral mucositis (OM) remains a significant unmet need for patients being treated with standard concomitant chemoradiation (CRT) regimens for head and neck cancers (HNC). OM's pathogenesis is complex and includes both direct and indirect damage pathways. In this paper, the field is reviewed with emphasis on the initiating and sustaining role of oxidative stress on OM's pathobiology. A hypothesis is presented which suggests that based on OM's clinical and biological trajectory, mucosal damage is largely the consequence of cumulative CRT-induced biological changes overwhelming physiologic self-protective mechanisms. Furthermore, an individual's ability to mount and maintain a protective response is dependent on interacting pathways which are primarily determined by a multiplex consisting of genomics, epigenomics, and microbiomics. Effective biologic or pharmacologic OM interventions are likely to supplement or stimulate existing physiologic damage-control mechanisms.

Robust pathway sampling in phenotype prediction. Application to triple negative breast cancer.

BACKGROUND: Phenotype prediction problems are usually considered ill-posed, as the amount of samples is very limited with respect to the scrutinized genetic probes. This fact complicates the sampling of the defective genetic pathways due to the high number of possible discriminatory genetic networks involved. In this research, we outline three novel sampling algorithms utilized to identify, classify and characterize the defective pathways in phenotype prediction problems, such as the Fisher's ratio sampler, the Holdout sampler and the Random sampler, and apply each one to the analysis of genetic pathways involved in tumor behavior and outcomes of triple negative breast cancers (TNBC). Altered biological pathways are identified using the most frequently sampled genes and are compared to those obtained via Bayesian Networks (BNs). RESULTS: Random, Fisher's ratio and Holdout samplers were more accurate and robust than BNs, while providing comparable insights about disease genomics. CONCLUSIONS: The three samplers tested are good alternatives to Bayesian Networks since they are less computationally demanding algorithms. Importantly, this analysis confirms the concept of "biological invariance" since the altered pathways should be independent of the sampling methodology and the classifier used for their inference. Nevertheless, still some modifications are needed in the Bayesian networks to be able to sample correctly the uncertainty space in phenotype prediction problems, since the probabilistic parameterization of the uncertainty space is not unique and the use of the optimum network might falsify the pathways analysis.

Impact of the insurance type of head and neck cancer patients on their hospitalization utilization patterns.

BACKGROUND: Head and neck cancer (HNC) patients with Medicaid, Medicare, or no insurance show poor outcomes in comparison with privately insured patients. It was hypothesized that nonprivate insurance coverage biases the selection of the treatment site to favor hospitals that are not associated with optimum treatment outcomes. This study assessed the relation between the insurance type of HNC patients and the hospital type for inpatient care. METHODS: Adult HNC patients were identified from the Nationwide Inpatient Sample (2012 and 2013). The primary exposure was the insurance provider type. The outcome was the hospital type, which was classified by the hospital's ownership and its location and teaching status. Multivariate multinomial logistic regression models were constructed to control for the patient's age, sex, race, income, mortality risk, and geographic location. The analysis was weighted and was adjusted for multiple comparisons. RESULTS: In all, 37,466 HNC patients representing 187,330 patients nationally were identified. After adjustments for age, sex, race, income, and mortality risk, in comparison with privately insured patients, Medicaid, Medicare, and uninsured patients demonstrated 1.14 to 2.29 increased odds of undergoing treatment at rural, urban nonteaching, private investor-owned, or government (nonfederal) hospitals (P < .05). This trend remained apparent even after adjustments for the geographic location. CONCLUSIONS: Uninsured patients or patients insured by government programs predominantly underwent care for HNC at hospital types most often associated with inferior survival outcomes. This finding could explain some proportion of insurance-related disparities in HNC outcomes. Further studies are warranted to determine whether interventions to promote equitable access to optimal hospital settings for patients, regardless of their insurance type, might improve outcomes among nonprivate insurance holders. Cancer 2018;124:760-8. © 2017 American Cancer Society.

The Use of Hyperbaric Oxygen for the Prevention and Management of Osteoradionecrosis of the Jaw: A Dana-Farber/Brigham and Women's Cancer Center Multidisciplinary Guideline.

BACKGROUND: Osteoradionecrosis of the jaw (ORN) is an infrequent yet potentially devastating complication of radiation therapy to the head and neck region. Treatment options include antimicrobial therapy, local sequestrectomy, resection, and the use of hyperbaric oxygen (HBO). Published data on ORN are difficult to compare because of the lack of a universally accepted classification and staging system, and the literature on the use of HBO to either prevent or successfully manage ORN is controversial and inconclusive. Therefore, we aimed to establish a standard approach for using HBO at our institution. MATERIALS AND METHODS: A literature search was conducted of articles published in the English language between January 1980 and January 2016. Retrieved articles were evaluated by two independent reviewers. Isolated case reports, abstracts, case series, review articles, and cohort studies without a control group were excluded; summary data were extracted from the remaining studies. A panel of experts from Head and Neck Oncology and Oral Medicine from the Dana-Farber Cancer Institute and Brigham and Women's Hospital reviewed the summary data and established multidisciplinary guidelines on the use of HBO for the prevention and management of ORN. RESULTS: Seven studies were evaluated and reviewed by the multidisciplinary panel. There was no consistent evidence in support of HBO for either the prevention or management of ORN. CONCLUSION: Based on the available evidence and expert opinion, routine use of HBO for the prevention or management of ORN is not recommended and is rarely used at our institution. The Oncologist 2017;22:343-350 IMPLICATIONS FOR PRACTICE: The Division of Head and Neck Oncology of Dana-Farber/Brigham and Women's Cancer Center does not recommend the routine use of HBO for the prevention or management of ORN. Adjunctive HBO may be considered for use on a case-by-case basis in patients considered to be at exceptionally high risk who have failed conservative therapy and subsequent surgical resection.

Genomic data integration in chronic lymphocytic leukemia.

BACKGROUND: B-cell chronic lymphocytic leukemia (CLL) is a heterogeneous disease and the most common adult leukemia in western countries. IgVH mutational status distinguishes two major types of CLL, each associated with a different prognosis and survival. Sequencing identified NOTCH1 and SF3B1 as the two main recurrent mutations. We described a novel method to clarify how these mutations affect gene expression by finding small-scale signatures that predict the IgVH, NOTCH1 and SF3B1 mutations. We subsequently defined the biological pathways and correlation networks involved in disease development, with the potential goal of identifying new drugable targets. METHODS: We modeled a microarray dataset consisting of 48807 probes derived from 163 samples. The use of Fisher's ratio and fold change combined with feature elimination allowed us to identify the minimum number of genes with the highest predictive mutation power and, subsequently, we applied network and pathway analyses of these genes to identify their biological roles. RESULTS: The mutational status of the patients was accurately predicted (94-99%) using small-scale gene signatures: 13 genes for IgVH, 60 for NOTCH1 and 22 for SF3B1. LPL plays an important role in the case of the IgVH mutation, whereas MSI2, LTK, TFEC and CNTAP2 are involved in the NOTCH1 mutation, and RPL32 and PLAGL1 are involved in the SF3B1 mutation. Four high discriminatory genes (IGHG1, MYBL1, NRIP1 and RGS1) are common to these three mutations. The IL-4-mediated signaling events pathway appears to be involved as a common mechanism and suggests an important role of the immune response mechanisms and antigen presentation. CONCLUSIONS: This retrospective analysis served to provide a deeper understanding of the effects of the different mutations in CLL disease progression, with the expectation that these findings will be clinically applied in the near future to the development of new drugs.

Cytokine-mediated blood brain barrier disruption as a conduit for cancer/chemotherapy-associated neurotoxicity and cognitive dysfunction.

Neurotoxicity is a common side effect of chemotherapy treatment, with unclear molecular mechanisms. Clinical studies suggest that the most frequent neurotoxic adverse events affect memory and learning, attention, concentration, processing speeds and executive function. Emerging preclinical research points toward direct cellular toxicity and induction of neuroinflammation as key drivers of neurotoxicity and subsequent cognitive impairment. Emerging data now show detectable levels of some chemotherapeutic agents within the CNS, indicating potential disruption of blood brain barrier integrity or transport mechanisms. Blood brain barrier disruption is a key aspect of many neurocognitive disorders, particularly those characterized by a proinflammatory state. Importantly, many proinflammatory mediators able to modulate the blood brain barrier are generated by tissues and organs that are targets for chemotherapy-associated toxicities. This review therefore aims to explore the hypothesis that peripherally derived inflammatory cytokines disrupt blood brain barrier permeability, thereby increasing direct access of chemotherapeutic agents into the CNS to facilitate neuroinflammation and central neurotoxicity.

Could the PI3K canonical pathway be a common link between chronic inflammatory conditions and oral carcinogenesis?

The association between chronic inflammatory disorders and oral carcinogenesis has been both a source of interest and contention. Based upon its central importance in oral carcinogenesis, the finding that the PI3k/Akt/mTOR pathway is activated in oral lichen planus, chronic graft-versus-host disease, and chronic oral candidiasis suggests that it may provide a link between benign and malignant oral conditions. Here, we discuss a possible mechanistic rationale that addresses the activation of this important signaling pathway and its downstream events, while correlating it with the carcinogenic potential of chronic oral disorders.

Sensitivity analysis of gene ranking methods in phenotype prediction.

INTRODUCTION: It has become clear that noise generated during the assay and analytical processes has the ability to disrupt accurate interpretation of genomic studies. Not only does such noise impact the scientific validity and costs of studies, but when assessed in the context of clinically translatable indications such as phenotype prediction, it can lead to inaccurate conclusions that could ultimately impact patients. We applied a sequence of ranking methods to damp noise associated with microarray outputs, and then tested the utility of the approach in three disease indications using publically available datasets. MATERIALS AND METHODS: This study was performed in three phases. We first theoretically analyzed the effect of noise in phenotype prediction problems showing that it can be expressed as a modeling error that partially falsifies the pathways. Secondly, via synthetic modeling, we performed the sensitivity analysis for the main gene ranking methods to different types of noise. Finally, we studied the predictive accuracy of the gene lists provided by these ranking methods in synthetic data and in three different datasets related to cancer, rare and neurodegenerative diseases to better understand the translational aspects of our findings. RESULTS AND DISCUSSION: In the case of synthetic modeling, we showed that Fisher's Ratio (FR) was the most robust gene ranking method in terms of precision for all the types of noise at different levels. Significance Analysis of Microarrays (SAM) provided slightly lower performance and the rest of the methods (fold change, entropy and maximum percentile distance) were much less precise and accurate. The predictive accuracy of the smallest set of high discriminatory probes was similar for all the methods in the case of Gaussian and Log-Gaussian noise. In the case of class assignment noise, the predictive accuracy of SAM and FR is higher. Finally, for real datasets (Chronic Lymphocytic Leukemia, Inclusion Body Myositis and Amyotrophic Lateral Sclerosis) we found that FR and SAM provided the highest predictive accuracies with the smallest number of genes. Biological pathways were found with an expanded list of genes whose discriminatory power has been established via FR. CONCLUSIONS: We have shown that noise in expression data and class assignment partially falsifies the sets of discriminatory probes in phenotype prediction problems. FR and SAM better exploit the principle of parsimony and are able to find subsets with less number of high discriminatory genes. The predictive accuracy and the precision are two different metrics to select the important genes, since in the presence of noise the most predictive genes do not completely coincide with those that are related to the phenotype. Based on the synthetic results, FR and SAM are recommended to unravel the biological pathways that are involved in the disease development.

Low level laser therapy/photobiomodulation in the management of side effects of chemoradiation therapy in head and neck cancer: part 1: mechanisms of action, dosimetric, and safety considerations.

PURPOSE: There is a large body of evidence supporting the efficacy of low level laser therapy (LLLT), more recently termed photobiomodulation (PBM), for the management of oral mucositis (OM) in patients undergoing radiotherapy for head and neck cancer (HNC). Recent advances in PBM technology, together with a better understanding of mechanisms involved, may expand the applications for PBM in the management of other complications associated with HNC treatment. This article (part 1) describes PBM mechanisms of action, dosimetry, and safety aspects and, in doing so, provides a basis for a companion paper (part 2) which describes the potential breadth of potential applications of PBM in the management of side-effects of (chemo)radiation therapy in patients being treated for HNC and proposes PBM parameters. METHODS: This study is a narrative non-systematic review. RESULTS: We review PBM mechanisms of action and dosimetric considerations. Virtually, all conditions modulated by PBM (e.g., ulceration, inflammation, lymphedema, pain, fibrosis, neurological and muscular injury) are thought to be involved in the pathogenesis of (chemo)radiation therapy-induced complications in patients treated for HNC. The impact of PBM on tumor behavior and tumor response to treatment has been insufficiently studied. In vitro studies assessing the effect of PBM on tumor cells report conflicting results, perhaps attributable to inconsistencies of PBM power and dose. Nonetheless, the biological bases for the broad clinical activities ascribed to PBM have also been noted to be similar to those activities and pathways associated with negative tumor behaviors and impeded response to treatment. While there are no anecdotal descriptions of poor tumor outcomes in patients treated with PBM, confirming its neutrality with respect to cancer responsiveness is a critical priority. CONCLUSION: Based on its therapeutic effects, PBM may have utility in a broad range of oral, oropharyngeal, facial, and neck complications of HNC treatment. Although evidence suggests that PBM using LLLT is safe in HNC patients, more research is imperative and vigilance remains warranted to detect any potential adverse effects of PBM on cancer treatment outcomes and survival.

Mammalian target of rapamycin inhibitor-associated stomatitis in hematopoietic stem cell transplantation patients receiving sirolimus prophylaxis for graft-versus-host disease.

The mammalian target of rapamycin (mTOR) inhibitor sirolimus is effective in reducing incidence of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). Agents that inhibit the mTOR pathway are known to be associated with significant and potentially dose-limiting toxicities, including stomatitis. The objective of this study was to report the clinical features and management outcomes of sirolimus-associated oral ulcers in the context of post-HSCT prophylaxis of GVHD. Seventeen patients, from a study cohort of 967, who were treated with sirolimus as prophylaxis for GVHD after allogeneic HSCT at the Dana-Farber/Brigham and Women's Cancer Center developed oral ulcers and were referred to the oral medicine clinic for evaluation and treatment over a period of 6 years. Clinical characteristics (appearance, anatomic site, size) and therapeutic outcomes (time to complete resolution) were documented. Median time to onset of oral ulceration was 55 days after allogeneic HSCT (range, 6 to 387 days); 92.9% of ulcers were located on nonkeratinized mucosa, with the ventrolateral tongue the most common site of involvement. Thirteen patients were treated with topical corticosteroid therapy; 12 of these patients also required intralesional corticosteroid injections. Clinical improvement (resolution of the lesions and improvement of symptoms) was noted in all cases, with no reported adverse events. Median time to complete resolution after onset of therapy was 14 days (range, 2 to 70 days). Patients receiving sirolimus for GVHD prophylaxis may develop painful oral ulcerations, which can be effectively managed with topical steroid treatment. Further prospective studies are needed to better elucidate the incidence of this complication, identify risk factors, and evaluate the effectiveness of interventions.

Mucositis: pathobiology and management.

PURPOSE OF REVIEW: Oral mucositis remains a frequent debilitating toxicity associated with drug and radiation regimens used to treat cancer. This review highlights the recent understanding of the biological basis, risk factors for, and management for oral mucositis. RECENT FINDINGS: Prevalence and incidence data for mucositis are inconsistent and often underreported. The pathogenesis of mucositis encompasses a sequence of biological events possibly influenced by the oral microbiome and environment. Despite its frequency and severity, there is currently no effective treatment available for the majority of patients at risk. However, with the better understanding of the pathogenesis of mucositis a number of new drugs and biological agents are under investigation. Genome-wide risk prediction tools will allow the identification of patients at risk of developing mucositis. SUMMARY: Oral mucositis is a common complication of cancer treatment that may negatively impact the patient's cancer treatment outcome. Despite its frequency and consequences, the lack of effective interventions has frustrated patients and caregivers. Fortunately, a broad range of mechanistically targeted compounds are being developed.

MASCC/ISOO clinical practice guidelines for the management of mucositis secondary to cancer therapy.

BACKGROUND: Mucositis is a highly significant, and sometimes dose-limiting, toxicity of cancer therapy. The goal of this systematic review was to update the Multinational Association of Supportive Care in Cancer and International Society of Oral Oncology (MASCC/ISOO) Clinical Practice Guidelines for mucositis. METHODS: A literature search was conducted to identify eligible published articles, based on predefined inclusion/exclusion criteria. Each article was independently reviewed by 2 reviewers. Studies were rated according to the presence of major and minor flaws as per previously published criteria. The body of evidence for each intervention, in each treatment setting, was assigned a level of evidence, based on previously published criteria. Guidelines were developed based on the level of evidence, with 3 possible guideline determinations: recommendation, suggestion, or no guideline possible. RESULTS: The literature search identified 8279 papers, 1032 of which were retrieved for detailed evaluation based on titles and abstracts. Of these, 570 qualified for final inclusion in the systematic reviews. Sixteen new guidelines were developed for or against the use of various interventions in specific treatment settings. In total, the MASCC/ISOO Mucositis Guidelines now include 32 guidelines: 22 for oral mucositis and 10 for gastrointestinal mucositis. This article describes these updated guidelines. CONCLUSIONS: The updated MASCC/ISOO Clinical Practice Guidelines for mucositis will help clinicians provide evidence-based management of mucositis secondary to cancer therapy.