Dental anomalies among childhood cancer survivors

a systematic review

Abstract

Introduction/Justification: Childhood cancer corresponds to a disordered proliferation of abnormal cells, resulting in malignant lesions that can manifest in any part of the body in individuals aged 0–19 years (INCA, 2022). In recent decades, the prognosis of pediatric cancer has improved due to significant increases in survival rates and life expectancy. This improvement is attributed to the higher efficacy of antineoplastic treatment protocols, typically involving multi-agent chemotherapy, radiotherapy, or their combination to achieve optimal therapeutic outcomes (Siegel, 2021). However, multimodal treatments present a high risk of severe late effects, with oral manifestations occurring either early or late. Patients younger than 5 years are at increased risk for dental abnormalities, likely due to the intense activity of stem cells during odontogenesis, when permanent teeth are still developing (Çetiner et al., 2019). During treatment, acute oral effects include mucositis, periodontal alterations, taste disturbances, secondary infections, salivary gland dysfunction, and radio- or chemo-induced osteonecrosis. Late effects encompass caries and dental anomalies in number, shape, and structure, as well as disturbances in eruption, root development, and craniofacial growth (Mittal et al., 2017). Although not life-threatening, these alterations can significantly impact the quality of life of children and adolescents, compromising both aesthetic and functional aspects. Consequently, the clinical preparation of dentists and the conduct of longitudinal studies to assess functional outcomes are essential (Kang et al., 2018). Objective: To evaluate the prevalence of major dental anomalies in survivors of childhood cancer and their association with age at antineoplastic treatment. Methodology: This study is a systematic literature review aimed at analyzing and synthesizing the frequency of dental anomalies in childhood cancer survivors. The research steps included developing a thematic approach, formulating a search strategy in databases, collecting and analyzing selected primary studies, and organizing the results. The PICo strategy (Population, Interest, Context) was applied, where (P) comprised childhood cancer survivors, (I) dental malformations, and (Co) evaluated whether age at treatment represented a higher risk. Primary studies were searched in PubMed, Scopus, and the Virtual Health Library (BVS). Keywords were obtained from the DeCS/MeSH databases, combined with the Boolean operator AND: (cancer survivor) AND (tooth abnormalities). Inclusion criteria included cohort, case-control, and cross-sectional studies, published in English, with no date restriction. Exclusion criteria comprised studies that did not address dental developmental anomalies in children undergoing antineoplastic therapy, case reports, literature reviews, letters to the editor, and book chapters. Data collection was performed using the Rayyan tool, analyzing variables such as author, year of publication, sample size (n), age, sex, agenesis, microdontia, incomplete root formation, and taurodontism. Data were organized in Excel 2021, and study selection was conducted independently by two researchers based on title and abstract reading and application of inclusion criteria. Results/Discussion: The search, conducted in September 2024, identified 138 articles (PubMed: 41; BVS: 47; Scopus: 50). After applying inclusion and exclusion criteria, 46 studies were selected and 92 excluded (65 duplicates and the remainder for not addressing the topic, including literature reviews and case reports). The age of childhood cancer survivors ranged from 0 to 25 years, with no gender predilection. Microdontia was the most frequently reported anomaly (37 articles), followed by agenesis (31 articles), incomplete root formation (22 articles), and taurodontism (6 articles). A single study could report multiple anomalies. Microdontia showed high prevalence in some studies, such as Kim et al. (2022), with 94.8% (n=153), and Kaste et al. (2009), with 785 cases (n=9,308), whereas agenesis ranged from 5% (n=120) (Atif et al., 2021) to 80% (n=18) (Holtta et al., 2002). Incomplete root formation also showed variable frequency, with high values such as 99.3% (n=153) (Kim et al., 2022), 72% (n=88) (Defabianis et al., 2023), and 464 cases (n=9,308) (Kaste et al., 2009), while other studies reported low occurrence, such as 0.5% (n=196) (Kang et al., 2018). Taurodontism prevalence included 34% (n=208) (Quispe et al., 2019) and 17.4% (n=109) (Blanco et al., 2022). Data presentation was heterogeneous, including percentages, number of teeth, dental groups, and case counts, with some studies lacking quantitative information. These findings suggest that these anomalies result from the toxic effects induced by treatment and vary according to the stage of dental development during therapy. Microdontia likely results from dental organ atrophy, whereas agenesis indicates complete organ compromise, predominantly in younger patients. In cases of incomplete root formation and taurodontism, root development is impaired, ranging from root absence or shortening to enlargement of the pulp chamber. Thus, the severity of dental disturbances is closely related to the stage of tooth development and, consequently, to the child’s age at diagnosis and treatment. Consistently, microdontia and dental agenesis were more frequent in patients treated before 5 years of age, as pathogenic events during this period affect teeth at a very early developmental stage. Conclusion: Microdontia, agenesis, incomplete root formation, and taurodontism are the main dental anomalies observed in childhood cancer survivors, with their occurrence and severity influenced by age at treatment. These findings reinforce the importance of early and continuous dental follow-up, as well as the need for longitudinal studies.