Assesment of functional gastrointestinal diseases in obese children.

Functional gastrointestinal disorders (FGID) are disorders of gut-brain interactions characterized by chronic recurrent gastrointestinal symptoms and are reported to be more common in obese individuals. The aim of the study was to evaluate FGID in obese children. A total of 405 children (6-18 years) were enrolled in this cross sectional study. The children were divided into two groups according to body mass index (BMI) as < 85th percentile and > 95th percentile. Diagnosis of FGID was based on ROME VI criteria. Demographic and clinical characteristics of the patients were evaluated. FGID and subgroups were determined. The mean age of the children was 12.73 ± 3.17 years; 52% (n = 211) of them was female and 47.9% (n = 194) was male. A total of 50.6% patients had BMI > 95th percentile, and 55.1% of those patients had FGID. The subgroups of FGID, functional abdominal pain disorders and functional defecation disorders were significantly more common in obese children than non-obese group (P < 0.01). Additionally, constipation-predominant irritable bowel syndrome (IBS), diarrhea-predominant IBS, functional diarrhea, and abdominal distention were significantly more common in obese children than non-obese children (P < 0.01). CONCLUSION:  FGID in obese children was found to be increased significantly. Assessment of functional gastrointestinal symptoms in obese children will prevent unnecessary examinations. WHAT IS KNOWN: • Functional gastrointestinal disorders are reported to be more common in obese individuals. WHAT IS NEW: • Functional abdominal pain disorders and functional defecation disorders were significantly more common in obese children than non-obese group. • Constipation-predominant irritable bowel syndrome (IBS), diarrhea-predominant IBS, functional diarrhea, and abdominal distention were significantly more common in obese children than non-obese children.

Relationship between disease activity index and sleep disorders in children with inflammatory bowel diseases.

The aim of the study was to assess the prevalence of sleep disturbance in pediatric IBD patients and evaluate the relationship between clinical features of IBD, disease activity, inflammatory markers and quality of sleep. A total of 99 patients who were followed-up with the diagnosis of IBD (44 Crohn's disease (CD), 55 Ulcerative colitis (UC)) between 2015-2020 and 80 healthy controls were enrolled in the study. The clinical and demographic characteristics, laboratory parameters and disease activities were obtained from medical reports retrospectively. Pittsburgh sleep quality index (PSQI) was administered to all participants. PSQI score was significantly higher in patient group than the control group (P < 0.001). The sleep time of patient group, especially patients with UC was later than the control group (P = 0.008). Sleep duration was longer in control group than the patient group (P < 0.001). A positive strong correlation was obtained in disease activity index (r = 0.886; P < 0.001) and abdominal pain (r = 0.781; P < 0.001) with PSQI scores of CD patients. Disease activity index, rectal bleeding, diarrhea and number of stool had statistically significant positive strong correlation with PSQI scores of UC patients (P < 0.001). Pediatric Crohn's disease activity index and Pediatric ulcerative colitis activity index were the only independent risk factors affecting sleep disturbances (80% sensitivity and 91.67% specificity, 93.1% sensitivity and %96.15 specificity, respectively).   Conclusion: Increased disease activity has adverse effects on sleep quality. PSQI and PCDAI were strong tests for predicting sleep disorders in pediatric patients with IBD. What is Known: • Sleep disturbances are common complaint in inflammatory bowel disease (IBD), even in clinical remission. • Pittsburgh sleep quality index (PSQI) was used to evaluate the subjective sleep quality of patients. What is New: • PSQI and Pediatric Crohn Disease Activity index (PCDAI) were strong tests for predicting sleep disorders in pediatric patients with IBD. • PSQI and PCDAI scores correlated significantly with the severity of the sleep disturbances.

A simple machine learning approach for preoperative diagnosis of esophageal burns after caustic substance ingestion in children.

PURPOSE: The unresolved debate about the management of corrosive ingestion is a major problem both for the patients and healthcare systems. This study aims to demonstrate the presence and the severity of the esophageal burn after caustic substance ingestion can be predicted with complete blood count parameters. METHODS: A multicenter, national, retrospective cohort study was performed on all caustic substance cases between 2000 and 2018. The classification learner toolbox of MATLAB version R2021a was used for the classification problem. Machine learning algorithms were used to forecast caustic burn. RESULTS: Among 1839 patients, 142 patients (7.7%) had burns. The type of the caustic and the PDW (platelet distribution width) values were the most important predictors. In the acid group, the AUC (area under curve) value was 84% while it was 70% in the alkaline group. The external validation had 85.17% accuracy in the acidic group and 91.66% in the alkaline group. CONCLUSIONS: Artificial intelligence systems have a high potential to be used in the prediction of caustic burns in pediatric age groups.

Association of celiac disease with eosophageal eosinophilia and eosinophilic eosophagitis.

BACKGROUND: Aim of the study was to evaluate the association between celiac disease and eosinophilic oesophagitis/oesophageal eosinophilia in children. METHODS: A total of 278 patients with celiac disease (mean age: 7.12 ± 4.64 years, M/F: 0.77) were involved in the study. The patients were evaluated retrospectively in terms of clinical, endoscopic and histopathological findings. The association between celiac disease and eosinophilic oesophagitis/oesophageal eosinophilia was determined. RESULTS: According to Marsh classification system 6 (2.1%) of the patients were graded type 3A, 10 (3.5%) were type 3B, 262 (94.4%) were type 3C. The histopathological examination of oesophageal biopsy specimens of the patients revealed <15 eosinophils per high power field in only 4 (1.4%) patients. Two of these patients were positive for HLA DQ8, one was DQ2, and the other one was both DQ8 and DQ2. Tissue transglutaminase IgA level was above 300 U/mL in these patients. None of them had elevated serum total IgE levels, peripheral eosinophilia and history of atopic diseases. The gastrointestinal symptoms resolved and tissue transglutaminase IgA level of the patients were declined after 3 months of gluten-free diet. CONCLUSION: Although an association between celiac disease and eosinophilic oesophagitis/oesophageal eosinophilia have been postulated in recent years, no exact relationship was established in this study. This is the first study reporting the performance of follow-up GI endoscopy with biopsies revealing the resolution of oesophageal eosinophilia.

A rare cause of pancreatic insufficiency; Johanson Blizzard Syndrome.

Johanson-Blizzard Syndrome (JBS) was first described by Johanson and Blizzard. It exhibits autosomal recessive inheritance and is characterized by mutation in the UBR1 gene on the long arm of Chromosome 15. The phenotypic features as well as diarrhoea that occurs due to the exocrine pancreatic insufficiency constitute the main clinical symptoms. This article discusses Johanson-Blizzard Syndrome due to the case followed-up by us with the symptoms of deafness and diarrhoea as well as typical facial appearance.

The investigation of Helicobacter pylori in the dental biofilm and saliva samples of children with dyspeptic complaints.

BACKGROUND: The oral cavity can be an extra-gastric reservoir for Helicobacter pylori (H.pylori). This can play a role in the pathogenesis of halitosis, glossitis, recurrent aphthous stomatitis, and dental caries. The present study was conducted to detect the presence of H.pylori within the dental biofilm and in saliva samples collected from children suffering from dyspepsia and children without any gastrointestinal complaints. Associations with gastric infection, halitosis, and some oral parameters were also evaluated. METHODS: Seventy children (aged between 5-16) with dyspepsia were selected for the study group and control group composed of 30 healthy children without dyspepsia were also included in the study. After detailed oral and clinical examinations for oral parameters, saliva, and supragingival dental biofilm samples were collected for 16S rRNA and 23S rRNA genes detection by real-time polymerase chain reaction (RT-PCR). The presence of gastric H.pylori was evaluated in endoscopic biopsy specimens histopathologically. Halitosis was evaluated by benzoyl-DL-arginine-naphthylamid (BANA) test. Salivary S.mutans and Lactobacilli sp. counts were also carried out by commercial kits. RESULTS: H.pylori was histopathologically detected amongst 83% of the children with the dyspeptic condition. The detection rate of this bacteria in dental biofilm and saliva samples and halitosis were found relatively higher in the dyspeptic children rather than the control group (p < 0.01). Halitosis was not significantly different between dyspeptic children and those detected with H.pylori (p > 0.05). In the gastric H.pylori positive group with dyspepsia, DMFT/S and dmft/s numbers and plaque indices were found higher than the control group (p < 0.01). Only plaque indices of gastric H.pylori negative group with dyspepsia were found higher than the control group (p < 0.01). S.mutans and Lactobacilli sp. counts were not significantly different between gastric H.pylori positive and negative groups (p > 0.05). Comparing to those with negative for both genes, in children whose dental biofilm and saliva samples were positive for both 16S rRNA and 23S rRNA genes, significantly higher results for halitosis, and DMFS numbers and significantly lower results for dmfs numbers and pH values were found (p < 0.01). CONCLUSIONS: Helicobacter pylori can occur in the oral cavity aside and independently from the stomach. However, the high number of bacteria in the oral cavities of children with gastric H.pylori, an association between the presence of H.pylori and halitosis, DMFS, and pH were found.

A rare cause of severe rectal bleeding: solitary rectal ulcer syndrome.

Solitary rectal ulcer syndrome is a rare benign disorder in children which often goes unrecognized or easily misdiagnosed with other common diseases. It usually presents with rectal bleeding, constipation, mucous discharge, prolonged straining, tenesmus, and lower abdominal pain. The rectal bleeding varies from a little fresh blood to severe hemorrhage that requires blood transfusion. We report herein a pediatric case of solitary rectal ulcer syndrome who admitted to pediatric emergency department with severe rectal bleeding for reminding this rare syndrome.

Growth, tolerance and safety outcomes with use of an extensively hydrolyzed casein-based formula in infants with cow's milk protein allergy.

Objective: To evaluate growth, tolerance and safety outcomes with use of an extensively hydrolyzed casein-based formula (eHCF) in infants with cow's milk protein allergy (CMPA). Methods: A total of 226 infants (mean ± SD age: 106.5 ± 39.5 days, 52.7% were girls) with CMPA who received eHCF comprising at least half of the daily dietary intake were included. Data on anthropometrics [weight for age (WFA), length for age (LFA) and weight for length (WFL) z-scores] were recorded at baseline (visit 1), while data on infant feeding and stool records, anthropometrics and Infant Feeding and Stool Patterns and Formula Satisfaction Questionnaires were recorded at visit 2 (on Days 15 ± 5) and visit 3 (on Days 30 ± 5). Results: From baseline to visit 2 and visit 3, WFA z-scores (from -0.60 ± 1.13 to -0.54 ± 1.09 at visit 2, and to -0.44 ± 1.05 at visit 3, p < 0.001) and WFL z-scores (from -0.80 ± 1.30 to -0.71 ± 1.22 at visit 2, and to -0.64 ± 1.13 at visit 3, p = 0.002) were significantly increased. At least half of infants never experienced irritability or feeding refusal (55.7%) and spit-up after feeding (50.2%). The majority of mothers were satisfied with the study formula (93.2%), and wished to continue using it (92.2%). Conclusions: In conclusion, eHCF was well-accepted and tolerated by an intended use population of infants ≤ 6 months of age with CMPA and enabled adequate volume consumption and improved growth indices within 30 days of utilization alongside a favorable gastrointestinal tolerance and a high level of parental satisfaction.

Lactoferrin levels in the gastric tissue of Helicobacter pylori-positive and -negative patients and its effect on anemia.

AIM: To determine gastric tissue lactoferrin (Lf) levels of Helicobacter pylori- (Hp-) positive and -negative patients and its effect on anemia. METHODS: Cases in which initial presentation was of abdominal pain and that were Hp-positive at endoscopy were included. Hp-positive cases and -negative controls were divided into two groups. RESULTS: The study included 64 cases (average: 10.2 ± 0.4 years, 39 male and 25 female). Lf levels were subsequently studied on 61 cases. 45 (73.8%) of these were Hp-positive, while 16 (22.2%) were Hp-negative. In Hp-positive cases, mean staining percentages and density of glands in the antral mucosa were 45.5 ± 4.7% and 1.9 ± 0.1, respectively. Hp-negative cases showed significantly different values of 17.8 ± 4.5% and 1.3 ± 0.2, respectively. Hemoglobin and serum ferritin values of Hp-positive cases were 12.7 ± 0.2 g/dL and 32.5 ± 2 ng/mL, but these were comparable with Hp-negative cases (12.6 ± 0.1 g/dL and 30.7 ± 4.4 ng/mL). CONCLUSIONS: Tissue Lf was significantly higher in Hp-positive cases compared to Hp-negative cases, but no difference was observed between the two groups with regards to hemoglobin and ferritin level. As a result, it is difficult to say that this rise in Lf plays a role in the development of iron deficiency anemia in Hp-positive patients.

Turkish Translation, Validation, and Reliability Analysis of Pediatric Eosinophilic Esophagitis Symptom Severity Module Version 2.0.

The Paediatric Eosinophilic Esophagitis Symptom Severity Modules Version 2.0 (T-PEESv2.0) was developed in English as a valid, reliable questionnaire for follow up. This work aimed to develop a Turkish version of T-PEESv2.0 via translation and cultural adaptation and then to test its validation and reliability. Methods: The PEESv2.0 was translated into Turkish by standardized procedural steps completed in cooperation with the Mapi Research Trust. The final version of the questionnaire was submitted to eosinophilic oesophagitis patients or their parents at 2 times point separated by 1 week. An age-matched control group was used to test the discriminant validity. Construct validity was tested using the Wilcoxon test, and internal consistency was tested using Cronbach's alpha. Test-retest reliability was measured with Cohen's kappa and intraclass correlation coefficient. Results: One hundred twenty-eight participants (70 patients, 58 parents) were enrolled. Fifty-eight (39.1%) of them completed T-PEESv2.0-parent by proxy and 70 (54.7%) were T-PEESv2.0. The Cronbach's alpha coefficient and intraclass correlation coefficient for test-retest reliability were >0.70 for both questionnaires and for all domain (frequency and severity) and total scores. For discriminant validity analysis, subscale (frequency and domain) and total scores of the patient group were compared with those of the control group. The subscale and total scores were significantly different between the groups (P < 0.05). Conclusion: T-PEESv2.0 appeared to be valid and reliable, ready to be introduced as a clinical and research tool for the assessment of patients with eosinophilic oesophagitis.

Frequency of Asthma and Atopic Diseases in Inflammatory Bowel Disease and Celiac Disease.

OBJECTIVE: To compare the frequency of asthma and allergic diseases in patients with inflammatory bowel disease and Celiac disease using international study of asthma and allergies in childhood questionnaire. STUDY DESIGN: Cross-sectional, descriptive study. PLACE AND DURATION OF STUDY: Pediatric gastroenterology outpatient clinics and pediatric pulmonology outpatient clinics, from May 2015 to August 2015. METHODOLOGY: Patients aged between 6 and 18 years with the diagnoses of celiac and inflammatory bowel disease were included in the study. After recording the socio-demographic characteristics of all patients, the International study of asthma and allergies in childhood questionnaire was applied and required information collected. RESULTS: Eighty-three patients (31 males, 52 females) diagnosed with celiac, 42 patients (24 males, 18 females) diagnosed with ulcerative colitis, and 28 patients (11 females, 17 males) diagnosed with Crohn's disease were included. No significant difference was found between the groups in terms of the frequency of wheezing, wheezing in the last year, lifelong allergic rhinitis, long-term use of nasal steroids, and history of eczema (p >0.05). The frequency of atopic dermatitis was significantly higher in the celiac disease group than the other groups. CONCLUSION: The frequencies of asthma and atopy are similar in patients with celiac disease and inflammatory bowel disease.

Clinical evaluation of dental enamel defects and oral findings in coeliac children.

PURPOSE: To examine dental hard and soft tissue changes of coeliac children in order to increase the awareness of the pediatric dentists in prediagnosis of especially undiagnosed coeliac disease. MATERIALS AND METHODS: Sixty children, 28 (46.7%) boys and 32 (53.3%) girls whose ages were between 6 to 16 years were included in the present study. Thirty children who had undergone endoscopy and diagnosed with the coeliac disease in the Sisli Hamidiye Etfal Hospital, Istanbul, Turkey, formed the study group. Also, thirty children clinically suspected of having the coeliac disease with the same gastrointestinal complaints had undergone endoscopy and proven not coeliac were chosen as the control group. Oral examination involved assessment of dentition and specific and unspecific dental enamel defects. Also, soft tissue lesions, clinical delay of the dental eruption, salivary flow rate, pH, and buffering capacity were examined. RESULTS: Twenty coeliac patients had enamel defects, however none in the control subjects. In the coeliac group, all enamel defects were diagnosed in permanent teeth and as specific in all children. Grade I dental enamel defects found mainly in the incisors. The clinical delayed eruption was observed in 10 (33.3%) of 30 coeliac children and none of the children in the control group. While the level of DMFT/S numbers and stimulated salivary flow rate were found significantly lower in the coeliac group, pH was found significantly higher. CONCLUSION: Oral cavity may be involved in coeliac disease and pediatric dentists can play an important role in the early diagnosis of the coeliac disease.

Are Synbiotics added to the Standard Therapy to eradicate Helicobacter pylori in Children Beneficial? A Randomized Controlled Study.

AIM: We aimed to evaluate the role of the addition of Bifidobacterium /actis-containing synbiotic to the triple therapy in the case of He/icobacter py/ori eradication, the dyspeptic symptoms, and reducing the side effects of antibiotics. MATERIALS AND METHODS: A total of 104 children aged between 5 and 17 years, who were histopathologically diagnosed with H. py/ori were enrolled in this study, of whom 100 were included in the analysis. Patients were randomly classified into two groups. In the first group, 50 patients were administered amoxicillin + clarithromycin + lansoprazole for 14 days and B. /actis-containing synbiotic. In the second group, 50 patients were treated with the standard triple therapy. All patients were given information after completion of therapy. RESULTS: H. py/ori eradication was achieved in 88% in group I who received standard therapy with additional synbiotic and 72% in group II (p = 0.046). The number of patients in the second group who suffered from abdominal pain between the 3rd and 14th day of the treatment was higher (p < 0.05). The addition of probiotics to the triple therapy significantly reduced the frequency of diarrhea, but no significant difference was detected in the frequency of metallic taste (p = 0.04, p = 0.418 respectively). CONCLUSION: The addition of synbiotic to the triple therapy is effective for eradicating H. py/ori infection in children and is usually helpful to reduce or eliminate dyspeptic symptoms like abdominal pain, diarrhea, and vomiting. This study suggest that improved tolerance to the eradication treatment also reduces the treatment failure by adding probiotics and encourages the future study using probiotic supplementation in H. py/ori treatment.How to cite this article: Sirvan BN, Usta MK, Kizilkan NU, Urganci N. Are Synbiotics added to the Standard Therapy to eradicate He/icobacter Py/ori in Children Beneficial? A Randomized Controlled Study. Euroasian J Hepato-Gastroenterol 2017;7(1):17-22.

Chronic hepatitis B in children with or without malignancies: a 13-year follow-up.

AIM: To evaluate the outcome of chronic hepatitis B (CHB) in children with or without malignancies. METHODS: Twenty four children (15 boys and 9 girls) with malignancies, followed up by the pediatric gastroenterology outpatient clinic for CHB between January 2000 and December 2013, were enrolled in the study (Group 1). Group 2 was formed with twenty five children (11 girls and 14 boys) diagnosed with CHB without malignancies. The data from the patients' records were compared between the two groups. RESULTS: Hepatitis B e antigen (HBeAg)/antiHBe seroconversion was observed in 3 patients (12.5%) in group 1 and 15 patients (60%) in group 2, with annual seroconversion rates of 1.61% and 16.6%, respectively, and the difference was significant (P<0.01). One patient (6.6%) in Group 1 and 9 patients (53%) in Group 2 showed HBeAg/antiHBe seroconversion after treatment and the difference between the two groups was significant (P<0.06) Loss of hepatitis B surface antigen was observed in one patient in each of group 1 and 2. No clinical, laboratory and imaging findings of liver disease were observed in any of the patients at the end of the study. CONCLUSION: HBeAg/antiHBe seroconversion rate was lower in patients who had recovered from cancer.

Does gluten-free diet protect children with celiac disease from low bone density?

OBJECTIVE: We aimed to assess the effect and duration of gluten-free diet on bone health in children with celiac disease in our study. METHODS: Sixty three patients with celiac disease (CD) formed the study group. They were divided into two subgroups according to their dietary compliance. Bone mineral density (BMD) values of the patients at two and five years of gluten-free diet (GFD) were determined. Findings : The relationship between BMD and compliance to GFD was found to be statistically significant (P<0.01). BMD z-scores were increased (0.12±0.15 and 0.10±0.14 units respectively) (P<0.01). The patients in group 1 and 2 had mean -1.18±0.83 and -2.06±0.73 z-scores in the first DXA. In the second DXA, these values were -1.10±0.73 and-1.94±0.93 respectively. CONCLUSION: Dietary compliance is important for bone health, and the time needed to normalize the BMD is not known. Patients with positive anti-endomysium antibody (EMA), poor dietary history and history of bone pain should be evaluated with DXA during follow-up.

Corrosive substance ingestion in children.

OBJECTIVES: To evaluate children who ingested corrosive substances, in terms of demographic features, nature of ingested substances, clinical findings, management and complications. METHODS: A total of 1709 cases aged between 0 and 16 y who ingested corrosive substance were analyzed retrospectively by evaluating the medical records of the patients. RESULTS: The mean age of the cases was 35.23 ± 30.65 mo and male:female ratio was 1.45. Forty one percent of corrosive substances causing intoxication contained NaOH. Thirty percent of the families consisted of 5 or more members. Fourteen percent of the mothers were illiterate. Stricture formation was observed in 29 (1.69 %) of the cases during follow-up. In 79.31 % of those cases alkaline substance ingestion was responsible for stricture development. It was found that stricture formation occurred more frequently among cases who were older than 5 y of age and this finding was statistically significant (p = 0.001). CONCLUSIONS: The cases older than 5 y of age with the diagnosis of grade 2b esophagitis must be followed up closely for the stricture formation. In order to protect children from corrosive ingestion, importance must be given to preventive measures such as education of families, keeping and storing these agents out of the reach of children and providing safety caps for these products.

High doses of methylprednisolone in the management of caustic esophageal burns.

OBJECTIVE: Caustic substance ingestion in childhood is a public health issue in developing countries, and several management protocols have been proposed to prevent the resulting esophageal strictures. The role of corticosteroids in preventing corrosive-induced strictures is controversial. Our aim was to study the influence of high doses of corticosteroids in preventing esophageal strictures. METHODS: Eighty-three children with a mean age of 4.10 6 2.63 years and with grade IIb esophageal burns (an esophagogastroscopy was performed within 24­48 hours of injury) due to corrosive substance ingestion were enrolled in our study between 2005 and 2008. Forty-two children (study group) received methylprednisolone (1 g/1.73 m2 per day for 3 days), ranitidine, ceftriaxone, and total parenteral nutrition. Forty-one children (control group) were administered the same regimen excluding methylprednisolone. Stricture development was compared between groups based on endoscopic and radiologic findings. RESULTS: During the endoscopic examination, stricture development was observed in 4 patients (10.8%) in the study group and in 12 patients (30%) in the control group. The difference was statistically significant (P = .038). The stricture development rate in the upper gastrointestinal system with barium meal was 14.3% and 45.0% in the study and control groups, respectively. The difference was statistically significant (P = .004). The duration of total parenteral nutrition was shorter in the study group compared with the control group (P = .001). High doses of methylprednisolone were well tolerated in the study group without any side effects. CONCLUSIONS: High doses of methylprednisolone used for the management of grade IIb esophageal burns may reduce stricture development.

A case report of malignant infantile osteopetrosis.

BACKGROUND: Malignant infantile osteopetrosis (MIOP) presents early in life with extreme sclerosis of the skeleton and reduction of bone marrow spaces. Since there is a defect in the bone marrow, the disease can cause anemia, extramedullary hematopoiesis secondary to anemia leading to hepatosplenomegaly, cranial nerves compression and severe growth failure. This disorder is often lethal within the first decade of life because of secondary infections. Stem cell transplantation (SCT) remains the only curative therapy. CASE PRESENTATION: We report a two-month old male infant, diagnosed as MIOP while investigating the cause of hepatosplenomegaly. The patient was referred for stem cell transplantation. CONCLUSION: Malignant infantile osteopetrosis should be kept in mind as a rare cause of hepatosplenomegaly and the patient should be referred for stem cell transplantation before neurologic or visual impairment develops.

Assessment of hepatitis B immunization status after antineoplastic therapy in children with cancer.

BACKGROUND AND OBJECTIVES: Hepatitis B is a disease that is preventable with vaccination. Antibody levels after vaccination may be affected by suppression of the immune system due to cancer therapy. Children with cancer have a high risk of hepatitis B virus (HBV) infection. We aimed to assess the pretreatment immunization status against HBV infection and the rate of continuity of immunization after therapy in children with cancer. DESIGN AND SETTING: Retrospective case review of patients treated from 2004 to 2008. PATIENTS AND METHODS: We reviewed the medical records of patients treated in the departments of pediatric hematology and oncology and collected data on immunization history and hepatitis B serology. Anti-HBs antibody titers were compared before and after treatment. RESULTS: This study included 159 (99 males, 60 females) children who had a serologic examination. Antineoplastic therapy had been given for acute leukemia (n=66), non-Hodgkin lymphoma (n=27), Hodgkin lymphoma (n=20), and solid tumors (n=46). Fifty-one patients had not been immunized against HBV prior to the therapy; HBV serology was negative in 49 of these patients and HBsAg was positive in 2 patients. Anti-HBs antibody positivity was present in 99 of 108 patients with an immunization history, whereas no vaccination response was present in 9 patients. The titer of anti-HBs antibody was decreased below the protection level in 33 (33%) patients with positive anti-HBs antibody, whereas the protection level was found to be maintained in 66 (67%) patients. The most significant decrease (63.6%) was observed in leukemia patients. Posttreatment HBsAg and HBV DNA positivity was detected in two of the patients with negative pretreatment serology, whereas no HBV infection developed in the group with positive anti-HBs antibody. CONCLUSIONS: This study demonstrated the importance of routine childhood vaccination in reducing the risk of HBV infection in patients with cancer.