The Gut Microbiome and Pediatric Cancer: Current Research and Gaps in Knowledge

Children's Oncology Group's 2023 blueprint for research: Cancer control and supportive care

The objective of the Cancer Control and Supportive Care (CCL) Committee in the Children's Oncology Group (COG) is to reduce the overall morbidity and mortality of therapy-related toxicities in children, adolescents, and young adults with cancer. We have targeted five major domains that cause clinically important toxicity: (i) infections and inflammation; (ii) malnutrition and metabolic dysfunction; (iii) chemotherapy-induced nausea and vomiting; (iv) neuro- and oto-toxicty; and (v) patient-reported outcomes and health-related quality of life. Subcommittees for each domain prioritize randomized controlled trials and biology aims to determine which strategies best mitigate the toxicities. The findings of these trials are impactful, informing clinical practice guidelines (CPGs) and directly leading to changes in the standard of care for oncology practice. With the development of new therapies, there will be new toxicities, and the COG CCL Committee is dedicated to developing interventions to minimize acute and delayed toxicities, lessen morbidity and mortality, and improve quality of life in pediatric and young adult patients with cancer.

A Cross-sectional Survey to Review Food Safety Practices Within Pediatric Oncology and Stem Cell Transplant Centers in the United Kingdom

FOOD SAFETY AND PEDIATRIC CANCER

Neutropenia is a common complication of chemotherapy, which poses a high risk of infection and mortality. Neutropenic diet has historically been recommended for those undergoing chemotherapy. The rationale is to reduce the risk of foodborne infection by avoiding foods considered to be of high microbial risk. However, evidence for this diet is limited, and there is a lack of national consensus guidelines.

AIM

Ascertain food safety advice across specialist centers providing high-dose chemotherapy for malignancy or stem cell transplants in the United Kingdom.

MATERIALS AND METHODS

Dietitians at 22 centers were contacted to complete a questionnaire regarding food safety guidance implemented at their center for pediatric patients undergoing high-dose chemotherapy or stem cell transplants. Questions related to restricted foods, specific guidelines implemented, ward food provision, and timings of food provision.

RESULTS

Sixteen centers responded (73%). Many aspects of neutropenic diet were consistent across centers; avoidance of unpasteurized dairy products (94%), raw/undercooked meat (94%), and unpasteurized pâté (88%). There was a lack of consistency regarding water sources used on wards and unpeeled fruits and vegetables.

CONCLUSIONS

Food safety guidance for neutropenic patients differs across centers, with some practices seeming outdated and nonevidence based. A national review of food safety guidance should be considered to provide a standardized approach.

High-dose thiotepa, in conjunction with melphalan, followed by autologous hematopoietic stem cell transplantation in patients with pediatric solid tumors, including brain tumors

Among pediatric malignancies, solid tumors, particularly within the central nervous system (CNS), are common. Thiotepa, a myeloablative, high-dose chemotherapeutic (HDT) treatment administered prior to autologous hematopoietic stem cell transplantation (HSCT), can cross the blood-brain barrier and rapidly penetrate the CNS. We evaluated thiotepa HDT in conjunction with melphalan in Japanese patients with pediatric CNS/non-CNS solid tumors in a multicenter, open-label, non-comparative study. Thiotepa (200 mg/m²/day) was administered intravenously (IV) over 24 h on days -12, -11, -5, and -4 before scheduled HSCT. Melphalan (70 mg/m²/day) was administered IV over 1 h on days -11, -5, and -4. The safety analysis population comprised 41 patients, of whom 16 (39.0%) had solid tumors and 25 (61.0%) had brain tumors. The most frequently reported adverse events were diarrhea (40/41 [97.6%] patients) and febrile neutropenia (34/41 [82.9%]). No unexpected safety events were observed, and no events resulted in death or treatment discontinuation. All patients experienced bone marrow suppression and 39/41 (95.1%) achieved engraftment (neutrophil count ≥500/mm³ for 3 consecutive days after HSCT). The survival rate at day 100 post-autologous HSCT was 100%. These data confirm the safety of IV thiotepa plus melphalan HDT prior to autologous HSCT for patients with pediatric CNS/non-CNS solid tumors. Trial registration: JapicCTI-173654.

Management of Nutritional Needs in Pediatric Oncology: A Consensus Statement

Simple Summary

Nutritional management is an underestimated issue in treating pediatric cancer, since a systematic approach is currently lacking. In this consensus statement, a cohort of 12 experts selected from four different tertiary pediatric oncology centers formulated 21 clinical questions regarding the identification and treatment of nutritional issues in children with cancer. These questions were discussed, and practical recommendations were provided. With this paper, we aimed to give consensus-based guidance for addressing the nutritional needs of children with cancer, filling a gap in the field.

Abstract

Malnutrition, intended as both overnutrition and undernutrition, is a common problem in children with cancer, impacting quality of life as well as survival. In addition, nutritional imbalances during childhood can significantly affect proper growth. Nevertheless, there is currently a lack of a systematic approach to this issue in the pediatric oncology population. To fill this gap, we aimed to provide practice recommendations for the uniform management of nutritional needs in children with cancer. Twenty-one clinical questions addressing evaluation and treatment of nutritional problems in children with cancer were formulated by selected members from four Italian Association of Pediatric Hematology and Oncology (AIEOP) centers and from the Survivorship Care and Nutritional Support Working Group of Alliance Against Cancer. A literature search in PubMed was performed; during two consensus meetings, all recommendations were discussed and finalized using the nominal group technique. Members representing every institution voted on each recommendation. Finally, recommendations were approved by all authors.

Pre-therapy fasting slows epithelial turnover and modulates the microbiota but fails to mitigate methotrexate-induced gastrointestinal mucositis

BACKGROUND

Recent findings by Tang et al. (2020) show dietary restriction (30%, 2 weeks) prevents methotrexate-induced mortality by modulation of the microbiota, specifically the expansion of Lactobacillus. While fundamentally insightful, upscaling this schedule is a major obstacle to clinical uptake. Here, we evaluate a safe and clinically achievable schedule of pre-therapy fasting for 48 h on microbiota composition, body composition and intestinal proliferation, and assess its impact on the severity of methotrexate-induced gastrointestinal mucositis using a validated preclinical rat model.

METHODS

Age- and weight-matched male Wistar rats were treated with a sublethal dose of 45 mg/kg methotrexate with or without pre-therapy fasting. The impact of acute fasting on epithelial proliferation, body composition and the microbiota was assessed using plasma citrulline, Ki67 immunohistochemistry, miniSpec and 16S rRNA sequencing. The severity of gastrointestinal mucositis was evaluated using plasma citrulline and body weight.

RESULTS

Whilst pre-therapy fasting slowed epithelial proliferation and increased microbial diversity and richness, it also induced significant weight loss and was unable to attenuate the severity of mucositis in both age- and weight-matched groups. In contrast to Tang et al., we saw no expansion of Lactobacillus following acute fasting.

CONCLUSIONS

Our findings suggest that the beneficial effects of acute fasting are masked by the detrimental effects on body weight and composition and lacking influence on Lactobacillus. Future studies should consider alternative fasting schedules or aim to induce comparable microbial and mucosal manipulation without compromising body composition using clinically feasible methods of dietary or microbial intervention.

Gut microbial composition difference between pediatric ALL survivors and siblings

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer with high cure rates leading to rising numbers of long-term survivors. Adult survivors of childhood ALL are at increased risk of obesity, cardiovascular disease, and other chronic illnesses. We hypothesize that ALL therapy is associated with long-term gut microbiome alterations that contribute to predisposition to chronic medical conditions. We conducted a pilot study to test whether differences can be detected between stool microbiota of pediatric ALL survivors and their siblings. Stool samples were collected from 38 individuals under age 19 who were at least 1 year after completion of therapy for ALL. Stool samples collected from 16 healthy siblings served as controls. 16S ribosomal RNA gene sequencing was performed on the stool samples. Comparing microbiota of survivors to sibling controls, no statistically significant differences were found in alpha or beta diversity. However, among the top 10 operational taxonomic units (OTUs) from component 1 in sparse partial least squares discriminant analysis (sPLS-DA) with different relative abundance in survivors versus siblings, OTUs mapping to the genus Faecalibacterium were depleted in survivors. Differences in gut microbial composition were found between pediatric survivors of childhood ALL and their siblings. Specifically, the protective Faecalibacterium is depleted in survivors, which is reminiscent of gut microbiota alteration found in adult survivors of childhood ALL and reported in obesity, suggesting that microbiota alterations in pediatric ALL survivors start in childhood and may play a role in predisposition to chronic illness in later years of survivorship.

Nutrition during childhood cancer treatment: current understanding and a path for future research

Proper nutritional status during cancer therapy has been recognised as being integral to a variety of health outcome measures, including overall survival, treatment tolerance, and quality of life. The prevalence of malnutrition, defined by WHO as either undernutrition or overnutrition, among children and adolescents with cancer is reported to be as high as 75%. Yet, over the past two decades there have been limited advances in elucidating the underlying pathophysiological drivers of malnutrition in this population. This effect has resulted in a paucity of research aimed at improving nutritional assessment and intervention among this group. This Review presents an in-depth discussion of the role of nutritional status in paediatric cancer care, as well as evolving avenues of investigation that might propel personalised nutrition into a viable reality. Thus, nutritional science might facilitate individualised intervention strategies, and thereby help to optimise clinical outcomes for patients and survivors of childhood cancer.