Predicting Severe Radiation Esophagitis in Patients With Locally Advanced Esophageal Squamous Cell Carcinoma Receiving Definitive Chemoradiotherapy: Construction and Validation of a Model Based in the Clinical and Dosimetric Parameters as Well as Inflammatory Indexes

A Dosimetric Comparative Study of Carbon-Ion Radiotherapy Versus X-ray Volumetric Modulated Arc Therapy for Stage III Non-Small-Cell Lung Cancer

BACKGROUND

Compared to photon beam, carbon-ion radiotherapy (CIRT) has both physical and biological advantages.

AIM

To examine whether two-dimensional (2D) CIRT is dosimetrically superior to photon beam volume-modulated arc therapy (VMAT) in protecting the normal tissues for stage III non-small-cell lung cancer (NSCLC).

SUBJECTS AND METHODS

A retrospective study was conducted. Thirteen patients with stage III NSCLC treated in our center with curative CIRT and a sham photon beam VMAT treatment planning with the same normal tissue dose constraints were included for analysis. Target dose distributions and the homogeneity index (HI) within the planning target volumes were compared.

RESULTS

Both CIRT and VMAT plans have good tumor coverage with no significant differences in D98, D95, and D50 of Planning target volume 1 (PTV1) between the two plans. The HIs between the two plans are similar. The HI of PTV2 is superior in the CIRT plan (CIRT vs. VMAT: 0.08 vs. 0.16, P < 0.05). In general, CIRT results in a lower dose of the organ-at-risk (OAR) than the photon plans. The V5, V10, V20, V30, V40, and Dmean of the contralateral lung in the CIRT plan are significantly lower than that of the photon VMAT. For the ipsilateral lung, the V5 of CIRT is significantly lower. The CIRT also had significantly lower spinal cord Dmax, esophageal Dmean and V50, V10 and V30 of bone, and V50 of the trachea and bronchial tree.

CONCLUSIONS

Compared with photon VMAT, 2D-CIRT using the passive beam scanning technique significantly reduces the radiation dose to the OARs in curative radiotherapy of stage III NSCLC, suggesting a better protection of the normal tissues.

Gut Microbiota Characteristics Are Associated With Severity of Acute Radiation-Induced Esophagitis

BACKGROUND

Acute radiation-induced esophagitis (ARIE) is one of the most debilitating complications in patients who receive thoracic radiotherapy, especially those with esophageal cancer (EC). There is little known about the impact of the characteristics of gut microbiota on the initiation and severity of ARIE.

MATERIALS AND METHODS

Gut microbiota samples of EC patients undergoing radiotherapy (n = 7) or concurrent chemoradiotherapy (n = 42) were collected at the start, middle, and end of the radiotherapy regimen. Assessment of patient-reported ARIE was also performed. Based on 16S rRNA gene sequencing, changes of the gut microbial community during the treatment regimen and correlations of the gut microbiota characteristics with the severity of ARIE were investigated.

RESULTS

There were significant associations of several properties of the gut microbiota with the severity of ARIE. The relative abundance of several genera in the phylum Proteobacteria increased significantly as mucositis severity increased. The predominant genera had characteristic changes during the treatment regimen, such as an increase of opportunistic pathogenic bacteria including Streptococcus. Patients with severe ARIE had significantly lower alpha diversity and a higher abundance of Fusobacterium before radiotherapy, but patients with mild ARIE were enriched in Klebsiella, Roseburia, Veillonella, Prevotella_9, Megasphaera, and Ruminococcus_2. A model combining these genera had the best performance in prediction of severe ARIE (area under the curve: 0.907).

CONCLUSION

The characteristics of gut microbiota before radiotherapy were associated with subsequent ARIE severity. Microbiota-based strategies have potential use for the early prediction of subsequent ARIE and for the selection of interventions that may prevent severe ARIE.