Comparison and Prognostic Analysis of Adjuvant Radiotherapy versus Salvage Radiotherapy for Treatment of Radically Resected Locally Advanced Esophageal Squamous Cell Carcinoma

Genetic variant of ADH1C for predicting survival in esophageal squamous cell cancer patients who underwent postoperative radiotherapy

Background: Single nucleotide polymorphisms (SNPs) of essential enzymes for alcohol metabolism ADH1B, ADH1C, and ALDH2 are commonly regarded as genetic biomarkers for esophageal squamous cell carcinoma (ESCC) susceptibility. However, there have not been any reports on relations between SNPs of these genes and the prognosis of postoperative radiotherapy in ESCC. The current study aimed to understand the associations between gene variants of alcohol metabolism and adjuvant radiotherapy’s prognosis in ESCC.

Methods: This study retrospectively analyzed 110 ESCC patients from our institution who received adjuvant radiotherapy after surgery. The SNPs of ADH1B rs1229984, ADH1C rs1789924, and ALDH2 rs671 were detected by Sanger sequencing using formalin-fixed paraffin-embedded tumor samples. A nomogram was drawn based on prognostic factors associated with overall survival (OS).

Results: ADH1C rs1789924 (C>T) was associated with poor DFS and OS in ESCC patients undergoing adjuvant radiotherapy. Multivariate analysis showed that ADH1C rs1789924 (C>T) was one of the independent prognosis factors of DFS and OS. However, the genotypes of ADH1B SNP rs1229984 and ALDH2 rs671 were not associated with differences in the PFS and OS of these patients. Compared with the AJCC staging system, the nomogram containing the ADH1C genotype can more effectively and accurately predict the survival time of ESCC after surgery and adjuvant radiotherapy.

Conclusion: ADH1C rs1789924 might be a prognostic genetic biomarker for ESCC patients undergoing surgery and postoperative radiotherapy.

mTOR-Mediated Antioxidant Activation in Solid Tumor Radioresistance

Radiotherapy is widely used for the treatment of cancer patients, but tumor radioresistance presents serious therapy challenges. Tumor radioresistance is closely related to high levels of mTOR signaling in tumor tissues. Therefore, targeting the mTOR pathway might be a strategy to promote solid tumor sensitivity to ionizing radiation. Radioresistance is associated with enhanced antioxidant mechanisms in cancer cells. Therefore, examination of the relationship between mTOR signaling and antioxidant mechanism-linked radioresistance is required for effective radiotherapy. In particular, the effect of mTOR signaling on antioxidant glutathione induction by the Keap1-NRF2-xCT pathway is described in this review. This review is expected to assist in the identification of therapeutic adjuvants to increase the efficacy of radiotherapy.

Dosimetric Predictors of Radiation Gastritis Due to Postoperative Intensity Modulated Irradiation Therapy in Patients with Esophageal Squamous Cell Carcinoma After Radical Esophagectomy

Objective: To explore the association between the incidence of acute radiation gastritis attributed to postoperative intensity modulated irradiation therapy (IMRT) and the dose volume of intrathoracic stomach of patients with esophageal squamous cell carcinoma (ESCC) after radical esophagectomy. Methods: The authors retrospectively collected the data of 49 ESCC patients who participated in postoperative IMRT treatment after radical esophagectomy, and analyzed the incidence of acute radiation gastritis during the treatment. Results: Among all the 49 patients, acute grade ≥2 radiation gastritis was observed in 19 patients (39%). Receiver operating characteristic (ROC) curve analysis showed that the physical variables, such as stomach D_max, D_mean, length of the whole stomach received 5-40 Gy (LSTT₅-LSTT₄₀), and V₁₀-V₅₀, were associated with acute radiation gastritis. Patients were grouped according to cutoff values in physical indicators obtained from the ROC curve. Other than V₅, the incidence of acute grade ≥2 radiation gastritis was significantly higher in the group with indicators above cutoff values than that below cutoff values, and the between-group difference was statistically significant in terms of physical indicators. Multivariate analysis suggested that LSTT₅ and V₄₀ could be acted as indicators to predict the incidence of acute grade ≥2 radiation gastritis. Conclusions: In the postoperative IMRT treatment for ESCC patients, protection of intrathoracic stomach is strongly recommended. Dose-volume histogram is a preferable predictive indicator for the occurrence of acute radiation gastritis, especially for the stomach LSTT₅ and V₄₀. Nevertheless, a larger sample size is needed to provide insight into the relevant study.

A retrospective study of pattern of recurrence after radical surgery for thoracic esophageal carcinoma with or without postoperative radiotherapy

The present study aimed to investigate the recurrence pattern of thoracic esophageal cancer (TEC) following radical surgery for guiding postoperative radiotherapy (PRT). Patterns of recurrence were analyzed in patients with recurrence for the first time after radical surgery at the First Affiliated Hospital of Anhui Medical University (Anhui, China) from January 2012 to December 2015. A total of 244 patients were reviewed in the study. The mean recurrence time for patients with PRT was >1 month longer than that for patients without PRT. The lymphatic, anastomotic and hematological recurrence ratios were 87.9 vs. 69.2%, 4.0 vs. 11.5% and 8.0 vs. 17.2%, respectively for patients without and with PRT. The most common recurrence regions were staion1 and station 2-4 (30.0 vs. 36.5% and 37.2% vs. 23.1%, respectively, for patients without and with PRT). The lymphatic recurrence of upper TEC was almost in station1 and station 2-4 (infield). The middle and lower TEC also had a high probability of lymphatic recurrence in station 1 and station 2-4 (totally 76.3 vs. 57.6% and 61.9 vs. 61.1%, respectively). The recurrence ratio significantly decreased in station 2-4 (infield) for middle TEC patients with PRT compared with patients without PRT (P=0.03), while no significant differences in the lymphatic recurrence ratios were observed in other regions (P>0.05). The differences of recurrence ratios in station 7, station 8 and celiac regions (infield) for lower TEC patients without and with PRT also demonstrated no statistical significance (P>0.05). The results of the present study indicated that the lower neck, supraclavicular regions and upper mediastinal regions (station 1, 2 and 4) should be included in the clinic target volume (CTV) for PRT, while lower mediastinal regions, celiac regions and anastomotic may not be included in CTV.