Factors Associated With Oral Mucositis Severity in Children Who Have Received Chemotherapy.

Oral mucositis (OM) is a major complication for pediatric oncology patients undergoing cancer therapy. This paper aimed to report on the relationship between OM severity and various patient factors as well as to compare 2 scales used to assess OM severity. The severity of 68 separate episodes of OM in 47 pediatric oncology patients who had received chemotherapy was regularly assessed using the Children's International Mucositis Evaluation Scale (ChIMES) and World Health Organization (WHO) scale. The mean time from the start of the patients' chemotherapy block to the onset of OM was 8.4 days (±4.0), the median duration of OM was 7.0 days (4.0, 10.5) and median admission duration was 7.0 days (4.5, 13.5). There was a significant relationship between the severity of OM and the duration of symptoms ( P <0.001), patient's admission length ( P <0.001) and low neutrophil count. With decreasing neutrophil count, the severity of OM and number of pain medications used increased. Neutrophil count recovery coincided with resolution of OM. No significant relationship was found between OM severity and the child's cancer diagnosis. The 2 scales used to measure OM severity showed substantial agreement.

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

BACKGROUND: Mucositis is a significant toxicity of cancer therapy with numerous systemic sequelae. 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 the management of mucositis. METHODS: The literature was reviewed systematically to identify interventions for mucositis. Studies were rated according to the presence of major and minor flaws according to previously published criteria. The body of evidence for each intervention and 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 guideline covers evidence from 1197 publications related to oral or gastrointestinal mucositis. Thirteen new guidelines were developed for or against the use of various interventions in specific treatment settings, and 11 previous guidelines were confirmed after aa review of new evidence. Thirteen previously established guidelines were carried over because there was no new evidence for these interventions. CONCLUSIONS: The updated MASCC/ISOO Clinical Practice Guidelines for mucositis provide professional health caregivers with a clinical setting-specific, evidence-based tool to help with the management of mucositis in patients who have cancer.

Systematic review of growth factors and cytokines for the management of oral mucositis in cancer patients and clinical practice guidelines.

PURPOSE: To update the clinical practice guidelines for the use of growth factors and cytokines for the prevention and/or treatment of oral mucositis (OM). METHODS: A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. The findings were added to the database used to develop the 2014 MASCC/ISOO clinical practice guidelines. Based on the evidence level, the following guidelines were determined: recommendation, suggestion, and no guideline possible. RESULTS: A total of 15 new papers were identified within the scope of this section and were merged with 51 papers that were reviewed in the previous guidelines update. Of these, 14, 5, 13, 2, and 1 were randomized controlled trials about KGF-1, G-CSF, GM-CSF, EGF, and erythropoietin, respectively. For the remaining agents there were no new RCTs. The previous recommendation for intravenous KGF-1 in patients undergoing autologous hematopoietic stem cell transplantation (HSCT) conditioned with high-dose chemotherapy and TBI-based regimens is confirmed. The previous suggestion against the use of topical GM-CSF for the prevention of OM in the setting of high-dose chemotherapy followed by autologous or allogeneic stem cell transplantation remains unchanged. CONCLUSIONS: Of the growth factors and cytokines studied for the management of OM, the evidence supports a recommendation in favor of KGF-1 and a suggestion against GM-CSF in certain clinical settings.

Histological analysis of 41 dentigerous cysts in a paediatric population.

BACKGROUND: Dentigerous cysts are usually of developmental nature but may be of inflammatory origin especially in paediatric populations. It is important to understand the histological features of dentigerous cysts to enable accurate diagnosis. The aim of this study is to present epidemiological, clinical features and histopathological features of dentigerous cysts seen in a paediatric tertiary referral hospital. METHOD: The medical, radiographic and histopathology records of the Department of Pathology, Women's and Children's Hospital, Adelaide, Australia, during January 1998 to December 2013 were reviewed for patients with dentigerous cysts. All cases were re-examined by a specialist oral pathologist, consultant paediatric pathologist and paediatric dentistry registrar. RESULTS: Forty-one cases of dentigerous cysts were found. Patients in the permanent dentition were most frequently affected. Male predilection was observed (male:female 2.42:1). The posterior mandible was the most frequently affected region (63.42%) although maxillary canines were the teeth most commonly associated with dentigerous cysts (29.27%). The majority of cases were incidental findings. Squamous epithelium showing pseudoepitheliomatous hyperplasia (46%) was frequently observed and was significantly present with thicker epithelium (P < 0.0001) and an acute and chronic inflammatory infiltrate (P < 0.001). Inflammatory infiltrate was seen in 75.6% of cases. CONCLUSIONS: The current study provides increased knowledge of the histological features of dentigerous cysts in a large retrospective series of paediatric patients and provides further evidence regarding the frequency of inflammatory dentigerous cysts.

Matrix metalloproteinase expression is altered in the small and large intestine following fractionated radiation in vivo.

PURPOSE: Radiotherapy-induced gut toxicity (RIGT) is associated with significant diarrhoea, pain and rectal bleeding. Matrix metalloproteinases (MMPs) have been reported to be involved in chemotherapy-induced gut toxicity and RIGT following single-dose irradiation in vivo. We therefore proposed MMPs would be involved in the pathobiology of RIGT following fractionated irradiation. METHODS: Dark Agouti rats were treated with fractionated radiation (3 × 2.5 Gy/week for 6 weeks). Rats were killed at 3, 6 and 15 weeks to represent acute and chronic toxicities. Sections of jejunum and colon were immunostained for MMP-1, MMP-2, MMP-9 and MMP-14. Relative mRNA expression in jejunum and colon was quantified by RT-PCR for MMP-1, MMP-2, MMP-9 and MMP-14. Western blotting was also conducted on jejunum and colon tissue collected at week 6 to determine protein levels of pro- and active MMP-2. RESULTS: MMP-2 total protein levels, determined by western blotting, significantly increased in both the jejunum (p = 0.0359) and the colon (p = 0.0134) 6 weeks into the fractionated radiation schedule. MMP-1, MMP-2, and MMP-14 mRNA expression significantly increased in the jejunum. MMP-2 mRNA expression was also significantly increased in the colon. Immunostaining of MMP-2 was observed to be increased in both crypt enterocytes and the lamina propria. CONCLUSIONS: MMP-2 plays a role in the pathobiology of gastrointestinal toxicities following fractionated irradiation. Whilst MMP-1 and MMP-14 mRNA expression was increased, this occurred only in the jejunum, suggesting MMPs are differentially involved in RIGT depending on the intestinal region. Further studies are needed to elucidate the role these mediators play in the development and potentiation of RIGT.

Fractionated abdominal irradiation induces intestinal microvascular changes in an in vivo model of radiotherapy-induced gut toxicity.

PURPOSE: Radiotherapy-induced gut toxicity (RIGT) is associated with diarrhoea, pain and rectal bleeding and can occur as an acute or chronic toxicity. The microvasculature has been shown to be altered in the development of RIGT; however, the features are not yet characterized. We hypothesized that apoptosis of microvascular cells would occur early in the gastrointestinal tract following fractionated irradiation, followed by late microvascular changes, including sclerosis and telangiectasis. METHODS: Female Dark Agouti rats were treated with a 6-week fractionated radiation schedule of 3 × 2.5 Gy doses per week localized to the abdomen. At 3, 6 and 15 weeks, the intestines were assessed for markers of acute and chronic injury including morphological changes, collagen deposition, apoptosis and proliferation. RESULTS: Apoptosis of microvascular cells significantly increased at 6 and 15 weeks in the jejunum (p = 0.0026 and p = 0.0062, respectively) and at 6 and 15 weeks in the colon (p < 0.0001 and p = 0.0005, respectively) in rats receiving fractionated radiation to the abdomen. Histopathological changes of the colon microvasculature were also seen from week 3, including thickening of the lamina propria and dilated, thickened, telangiectatic vessels. CONCLUSIONS: Findings of this study provide evidence of regional and timing-specific changes in the intestinal microvasculature in response to fractionated radiotherapy which may play a role in development of both acute and chronic RIGT.

A systematic review of oral herpetic viral infections in cancer patients: commonly used outcome measures and interventions.

PURPOSE: To review the literature for outcome measures for oral viral infections in cancer patients. A secondary aim was to update the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) clinical practice guidelines for the management of oral viral infections in cancer patients. METHODS: Databases were searched for articles published in the English language, 1981-2013. Studies that met the eligibility criteria were reviewed systematically. The data about the outcome measures were classified according to the aim of the study: prevention, treatment, or non-interventional. The results of interventional studies were compared to the 2010 MASCC/ISOO publication. RESULTS: Multiple clinical and laboratory tests were used to measure oral viral infections, with great variability between studies. Most of the studies were about Herpes Simplex Virus (HSV). The outcome measure that was most commonly used was the presence of HSV infection diagnosed based on a combination of suggestive clinical presentation with a positive laboratory result. HSV culture was the most commonly reported laboratory outcome measure. Acyclovir and valacyclovir were consistently reported to be efficacious in the management of oral herpetic infections. No new data on the quality of life and economic aspects was found. CONCLUSIONS: Considering the variability in outcome measures reported to assess oral herpetic infections the researcher should select carefully the appropriate measures based on the objective of the study. Acyclovir and valacyclovir are effective in the management of oral herpetic infections in patients receiving treatment for cancer. Studies on newer anti-viral drugs may be useful to address the issue of anti-viral resistance.

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.

Tight junction defects are seen in the buccal mucosa of patients receiving standard dose chemotherapy for cancer.

PURPOSE: Oral mucositis is one of the most common and debilitating side effects of chemotherapy treatment. Patients are often unable to eat and drink, which can lead to poor clinical outcomes and extensive resource utilisation. The primary aim of this study was to determine the molecular integrity of oral epithelial tight junctions in patients undergoing chemotherapy. The secondary aim was to correlate these changes with proinflammatory cytokines and matrix metalloproteinase profiles. METHODS: Patients (n = 23) were recruited from the Royal Adelaide Hospital between 2000 and 2003. Reach patient underwent two oral buccal mucosa biopsies (4 mm): one prior to chemotherapy treatment and a second one after chemotherapy treatment. Oral buccal mucosa biopsies were also taken from seven healthy volunteers with no history of cancer, chemo- or radiotherapy treatment or inflammatory disorders. Routine haematoxylin and eosin staining was performed to determine epithelial thickness. Immunohistochemical staining was performed for claudin-1, zonular occludens-1, occludin, interleukin-1ß, tumour necrosis factor, interleukin-6, matrix metalloproteinase-2 and metalloproteinase-9. RESULTS: Patients receiving standard dose chemotherapy had significant epithelial atrophy. Elevations in all cytokines and matrix metalloproteinases were seen, with significant lamina propria staining for interleukin-6 and tumour necrosis factor. Matrix metalloproteinase-2 appeared most upregulated within the oral epithelium. These changes coincided with altered tight junction staining properties. Changes in the staining intensity and localisation were both noted, with clear cytoplasmic staining for zonular occludens-1 and claudin-1 in patients treated with chemotherapy. CONCLUSIONS: Chemotherapy causes defects in oral tight junctions, coupled with altered cytokine and matrix metalloproteinase profiles. Tight junction disruption in the epithelium may contribute to ulcer development or lead to poor tissue integrity, and the timing of these events may be a target for preventative treatment.

Estimating the effect of childhood socioeconomic disadvantage on oral cancer in India using marginal structural models.

BACKGROUND: Early life socioeconomic disadvantage could affect adult health directly or indirectly. To the best of our knowledge, there are no studies of the direct effect of early life socioeconomic conditions on oral cancer occurrence in adult life. METHODS: We conducted a multicenter, hospital-based, case-control study in India between 2011 and 2012 on 180 histopathologically confirmed incident oral and/or oropharyngeal cancer cases, aged 18 years or more, and 272 controls that included hospital visitors, who were not diagnosed with any cancer in the same hospitals. Life-course data were collected on socioeconomic conditions, risk factors, and parental behavior through interview employing a life grid. The early life socioeconomic conditions measure was determined by occupation of the head of household in childhood. Adult socioeconomic measures included participant's education and current occupation of the head of household. Marginal structural models with stabilized inverse probability weights were used to estimate the controlled direct effects of early life socioeconomic conditions on oral cancer. RESULTS: The total effect model showed that those in the low socioeconomic conditions in the early years of childhood had 60% (risk ratio [RR] = 1.6 [95% confidence interval {CI} = 1.4, 1.9]) increased risk of oral cancer. From the marginal structural models, the estimated risk for developing oral cancer among those in low early life socioeconomic conditions was 50% (RR = 1.5 [95% CI = 1.4, 1.5]), 20% (RR = 1.2 [95% CI = 0.9, 1.7]), and 90% (RR = 1.9 [95% CI = 1.7, 2.2]) greater than those in the high socioeconomic conditions when controlled for smoking, chewing, and alcohol, respectively. When all the three mediators were controlled in a marginal structural model, the RR was 1.3 (95% CI = 1.0, 1.6). CONCLUSION: Early life low socioeconomic condition had a controlled direct effect on oral cancer when smoking, chewing tobacco, and alcohol were separately adjusted in marginal structural models.

The role of oral flora in the development of chemotherapy-induced oral mucositis.

Chemotherapy-induced mucositis is considered to be a major oncological problem, caused by the cytotoxic effects of cancer chemotherapy. In the last 10 years, there have been significant advances in the understanding of mucositis pathobiology. At the basic level, it is now well-understood that it is not just an epithelial process, but rather a complex interaction between epithelial and connective tissue compartments. There is also potential interaction between the oral microenvironment and the development of mucositis. Changes occur in the resident oral flora (commensal) throughout cancer treatment, and it is conceivable that these organisms and changes that occur may have an influence on the development of mucosal toxicity associated with cancer treatment. The aim of this review was to examine the potential contributions of oral microflora in the pathobiology of mucositis and identify pathways and interactions that could be targeted for therapeutic management of mucositis.

Involvement of matrix metalloproteinases (MMP-3 and MMP-9) in the pathogenesis of irinotecan-induced oral mucositis.

OBJECTIVES: Matrix metalloproteinases (MMPs) are involved in both maintenance of healthy mucosa and mediation of several pathologies. Recently, MMPs and their inhibitors have attracted attention as potential mediators of mucositis. We investigated tissue expression of MMP-3 and MMP-9 over time in a pre-clinical model of irinotecan-induced oral mucositis (OM). MATERIALS AND METHODS: Eighty-one female Dark Agouti rats received either a single dose of irinotecan (200 mg/kg) or vehicle control. Rats were killed at different time points over a 72-h period and tongue mucosa examined histologically. Tissue expression of MMP-3 and MMP-9 was characterized by standard qualitative immunohistochemistry. RESULTS AND DISCUSSION: Epithelial thickness was reduced without any ulceration in the oral mucosa early after chemotherapy. Epithelial atrophy was associated with significant (P < 0.05) upregulation of MMP-3 and MMP-9 in all layers of the oral epithelium. The increase of MMP-3 was also significant (P < 0.05) in lamina propria and submucosa. Most of changes in expression occurred early (1-6 h), coinciding with previously described upregulation of transcription factors and pro-inflammatory cytokines in OM. Tissue expression of MMP-3 and MMP-9 followed different patterns of change over time, suggesting involvement in various aspects of OM pathophysiology. CONCLUSIONS: These findings suggest vital roles played by MMP-3 and MMP-9 during OM pathophysiology. Further research is required to investigate the role of other MMPs and the naturally existing tissue inhibitors of MMPs. Research should also be directed to investigate beneficial effects of MMPs intervention therapies to prevent or reduce the severity of OM.

Predictive model for risk of severe gastrointestinal toxicity following chemotherapy using patient immune genetics and type of cancer: a pilot study.

PURPOSE: Severe chemotherapy-induced gastrointestinal toxicity (CIGT) is common and results in treatment delays, dose reductions, and potential premature treatment discontinuation. Currently, there is no diagnostic marker to predict CIGT. Proinflammatory cytokines, produced via toll-like receptor signaling, are key mediators of this toxicity. Hence, this pilot study investigated the association between immune genetic variability and severe CIGT risk. METHODS: Genomic DNA from 34 patients (10 with severe CIGT) who had received 5-fluoruracil-based chemotherapy regimens was analyzed for variants of IL-1B, IL-2, IL-6, IL-6R, IL-10, TNF-a, TGF-b, TLR2, TLR4, MD2, MYD88, BDNF, CRP, ICE, and OPRM1. Multivariate logistic regression created a prediction model of severe CIGT risk. RESULTS: There were no significant differences between patients with and without severe CIGT with regards to age, sex, type of cancer, or chemotherapy treatment regimens. The prediction model of severe CIGT risk included TLR2 and TNF-a genetic variability and cancer type (colorectal and gastric). This prediction model was both specific and sensitive, with a receiver operator characteristic area under the curve of 87.3 %. CONCLUSIONS: This is the first report of immune genetic variability, together with cancer type, being predictive of severe CIGT risk. These outcomes are being validated in a larger patient population.

Basic oral care for hematology-oncology patients and hematopoietic stem cell transplantation recipients: a position paper from the joint task force of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) and the European Society for Blood and Marrow Transplantation (EBMT).

PURPOSE: Hematology-oncology patients undergoing chemotherapy and hematopoietic stem cell transplantation (HSCT) recipients are at risk for oral complications which may cause significant morbidity and a potential risk of mortality. This emphasizes the importance of basic oral care prior to, during and following chemotherapy/HSCT. While scientific evidence is available to support some of the clinical practices used to manage the oral complications, expert opinion is needed to shape the current optimal protocols. METHODS: This position paper was developed by members of the Oral Care Study Group, Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) and the European Society for Blood and Marrow Transplantation (EBMT) in attempt to provide guidance to the health care providers managing these patient populations. RESULTS: The protocol on basic oral care outlined in this position paper is presented based on the following principles: prevention of infections, pain control, maintaining oral function, the interplay with managing oral complications of cancer treatment and improving quality of life. CONCLUSION: Using these fundamental elements, we developed a protocol to assist the health care provider and present a practical approach for basic oral care. Research is warranted to provide robust scientific evidence and to enhance this clinical protocol.

TLR4/PKC-mediated tight junction modulation: a clinical marker of chemotherapy-induced gut toxicity?

Chemotherapy-induced gut toxicity is a major clinical and economic burden to oncology practice. The mechanisms responsible for its development are ill defined, hampering the development of therapeutic interventions. In light of newly published research foci and clinical practice guidelines in supportive care in cancer, there has been renewed interest in the role tight junctions play in the pathobiology of chemotherapy-induced gut toxicity. Several preclinical studies have identified molecular defects in intestinal tight junctions following chemotherapy. Despite these findings, the mechanisms responsible for chemotherapy-induced tight junction disruption remain unclear. Recent research has highlighted roles for toll-like receptor 4 and protein kinase C signalling in the regulation of tight junctions. This critical review therefore aims to provide evidence linking toll-like receptor 4 expression, protein kinase C activation and tight junction disruption and their relationship to clinical toxicity.

Mammalian target of rapamycin inhibitor-associated stomatitis.

With the recent introduction of inhibitors of mammalian target of rapamycin (mTOR) in oncology, distinct cutaneous and oral adverse events have been identified. In fact, stomatitis and rash are documented as the most frequent and potentially dose-limiting side effects. Clinically, mTOR inhibitor-associated stomatitis (mIAS) more closely resembles aphthous stomatitis than oral mucositis due to conventional anticancer therapies. While most cases of mIAS are mild to moderate and self-limiting, more severe and persistent mIAS can become a dose-limiting toxicity. Small ulcerations may cause significant pain and mucosal sensitivity may occur in the absence of clinical changes. Use of clinical assessment tools that are primarily driven by ulceration size may underestimate mIAS, and assessment should include patient-reported outcomes. This article provides an up-to-date review of the clinical presentation, terminology, pathogenesis, assessment and management of mIAS and other mTOR inhibitor-associated oral adverse events. In addition, areas of future research are considered.

Implementation of a hospital oral care protocol and recording of oral mucositis in children receiving cancer treatment : a retrospective and a prospective study.

PURPOSE: This retrospective/prospective study was carried out to implement a standardized hospital oral care protocol and record the incidence of oral mucositis for inpatients with childhood cancer. METHODS: The implementation process included stages of collaboration, consultation, education, and evaluation. The retrospective part of the study documented the existing hospital oral care protocol and audited medical records of all pediatric patients diagnosed with cancer over a 12-month period. The frequency of recorded oral mucositis and the rate of referral to the pediatric dentistry department were assessed. Following evaluation of the retrospective study, the literature was searched to create a new hospital oral care protocol. Referral to the dental department was standardized and frequent in-service presentations were given to staff. The oral mucositis scale was recorded daily for all inpatients, and compliance rates were assessed. RESULTS: Fifty-nine patients' medical records were audited during the retrospective study. Oral mucositis prevalence was clearly documented at 34%, while an additional 20% lacked a definitive diagnosis. During the prospective study, 38 patients were followed and had a verified incidence of oral mucositis of 33%. The rate of compliance of implementing the oral mucositis scale improved from 41% during the first 4 months to 87% during last 3 months. Referral rates to the dental department increased from 53% during the retrospective study to 100% during the prospective study. CONCLUSIONS: Mutual understanding and collaboration between the oncology and dental departments in hospitals is crucial for standardizing patient care and for improving oral care standards.

Biomarkers of chemotherapy-induced diarrhoea: a clinical study of intestinal microbiome alterations, inflammation and circulating matrix metalloproteinases.

PURPOSE: A common side effect of chemotherapy treatment is diarrhoea. Unfortunately, the underlying mechanisms of chemotherapy-induced diarrhoea (CD) are poorly understood. We aimed to determine if faecal microbes of CD patients were displaced, if faecal calprotectin increased during CD and if there were alterations in circulating matrix metalloproteinases, nuclear factor kappa B (NF-κB), IL-1ß and TNF. PATIENTS AND METHODS: Twenty-six cancer patients receiving chemotherapy were enrolled and requested to provide stool samples and blood samples at various times during their chemotherapy cycle. Stool samples were analysed using conventional culture techniques and qRT-PCR. ELISA kits determined faecal calprotectin levels, levels of circulating matrix metalloproteinases and circulating NF-κB, IL-1ß and TNF. RESULTS: The majority of patients with CD showed decreases in Lactobacillus spp., Bifidobacterium spp., Bacteroides spp. and Enterococcus spp. Increases were observed in Escherichia coli and Staphylococcus spp. Methanogenic archaea were also quantified, with all patients except one showing a decrease. Faecal calprotectin levels were increased in 81.25 % of patients with CD. Circulating MMP-3 and MMP-9 significantly increased following chemotherapy. Circulating levels of NF-κB, IL-1ß and TNF were increased following chemotherapy, although this did not reach significance. CONCLUSIONS: We demonstrated that CD is associated with marked changes in intestinal microflora, methanogenic archaea, matrix metalloproteinase and serum levels of NF-κB, IL-1ß and TNF. These changes may result in diminished bacterial functions within the gut, altering gut function and initiating intestinal damage, resulting in the onset of diarrhoea. More importantly, these changes may provide clinicians with a possible new target for biomarkers of toxicity.

Emerging evidence on the pathobiology of mucositis.

BACKGROUND: Considerable progress has been made in our understanding of the biological basis for cancer therapy-induced mucosal barrier injury (mucositis). The last formal review of the subject by MASCC/ISOO was published in 2007; consequently, an update is timely. METHODS: Panel members reviewed the biomedical literature on mucositis pathobiology published between January 2005 and December 2011. RESULTS: Recent research has provided data on the contribution of tissue structure changes, inflammation and microbiome changes to the development of mucositis. Additional research has focused on targeted therapy-induced toxicity, toxicity clustering and the investigation of genetic polymorphisms in toxicity prediction. This review paper summarizes the recent evidence on these aspects of mucositis pathobiology. CONCLUSION: The ultimate goal of mucositis researchers is to identify the most appropriate targets for therapeutic interventions and to be able to predict toxicity risk and personalize interventions to genetically suitable patients. Continuing research efforts are needed to further our understanding of mucositis pathobiology and the pharmacogenomics of toxicity.

Emerging evidence on the pathobiology of mucositis.

BACKGROUND: Considerable progress has been made in our understanding of the biological basis for cancer therapy-induced mucosal barrier injury (mucositis). The last formal review of the subject by MASCC/ISOO was published in 2007; consequently, an update is timely. METHODS: Panel members reviewed the biomedical literature on mucositis pathobiology published between January 2005 and December 2011. RESULTS: Recent research has provided data on the contribution of tissue structure changes, inflammation and microbiome changes to the development of mucositis. Additional research has focused on targeted therapy-induced toxicity, toxicity clustering and the investigation of genetic polymorphisms in toxicity prediction. This review paper summarizes the recent evidence on these aspects of mucositis pathobiology. CONCLUSION: The ultimate goal of mucositis researchers is to identify the most appropriate targets for therapeutic interventions and to be able to predict toxicity risk and personalize interventions to genetically suitable patients. Continuing research efforts are needed to further our understanding of mucositis pathobiology and the pharmacogenomics of toxicity.