Abstract
Dear Editor,
We would like to congratulate Liu and colleagues 1 on their recent study, which aimed to investigate the longitudinal changes in oral mucositis (OM), a dose-limiting complication of radiotherapy (RT), and its influencing factors in 160 patients with head and neck cancers (HNCs). The prevalence and severity of OM was assessed before RT and first, second, third, fourth, fifth, and sixth weeks during RT. The prevalence of grade 3 to 4 OM was 0%, 0%, 2.5%, 9.4%, 26.9%, 24.4%, and 26.9% from the beginning until the sixth week of RT, respectively, indicating that severe OM peaks during the fourth week of RT and remains almost constant until the end of RT. The duration of diagnosis, clinical stage, N-stage, M-stage, surgery, diabetes, RT dose, oral hygiene, oral infection, oral pain, feeding route, and lymphocyte counts were identified as the factors significantly influencing OM in the multivariate analysis. These findings highlight the importance of adopting a comprehensive and multidisciplinary approach to preventing and treating OM due to its complex etiology and pathogenesis. The present study’s findings are of immense value to the scientific community. However, we would like to express 2 critical concerns essential for a comprehensive understanding of the study outcomes.
First, contrary to the existing literature, the authors could not demonstrate a significant link between the T-stage and OM prevalence in their multivariate analysis.2,3 However, a higher T-stage indicates a larger tumor size or neighboring tissue invasion, determining gross tumor volume and associated planning tumor volume (PTV). Consequently, a higher T-stage will result in larger low-, intermediate-, and high-risk PTV sizes, increasing the probability of overall and severe OM incidence due to exposure of larger mucosal volumes to 54 to 70 Gy.2-4 The similar assertion is also pertinent for the impact of use of concurrent chemotherapy based on the meta-analysis results reported by He and colleagues. 5 However, the apparent heterogeneities observed in cancer primaries, tumor stage, surgical status, and concurrent chemotherapy may have negated the significance of these factors in the study of Liu and colleagues. Consequently, a more comprehensive study with well-balanced tumor and treatment characteristics must be conducted to verify the validity of results and draw definitive conclusions on these issues.
And second, the authors claimed that “Also, N-stage and M-stage of cancer were equally used as risk factors for OM, possibly because cancers with lymph node involvement or metastases usually require a higher dose of radiation.” The lymph node involvement status, involved lymphatic levels, and the size of involved lymph nodes may determine the prescribed RT dosages and irradiated oral mucosa volume, all playing a role in determining the risk for OM.4,6 But, it is worth noting that irradiating metastatic HNC patients with curative doses is a rare practice and lacks solid evidence. Therefore, it is more likely that a higher OM risk in metastatic HNCs is associated with a hyperinflammatory and deprived immune state rather than higher RT doses.7,8 Therefore, the assertion of authors should not be considered a factual basis for using curative RT doses in metastatic HNC patients.
