Purpose: Lymphocytes are central players in systemic anti-tumor immune responses. In this study, we aimed to identify the relationship between absolute lymphocyte count (ALC) nadir during definitive radiotherapy (RT) and survival outcomes in patients with esophageal squamous cell carcinoma (ESCC), as well as evaluate the effect of RT parameters on ALC during RT. Materials and methods: We retrospectively reviewed 189 patients with stage I-IVA ESCC, who were treated with definitive RT at a single institution between 2012 and 2015. ALC values were assessed before, weekly during RT, and 1 month after the end of RT. Kaplan-Meier and Cox regression analyses were used to evaluate the relationship between ALC nadir during RT and patient outcomes. Predictors of low ALC nadir were assessed using univariate and multivariate logistic regression analyses. Results: The median ALC before treatment was 1.73 × 10 3 cells/µL. Fifty-eight (58.2) percent of the patients exhibited low ALC nadir (≤0.38 × 10 3 cells/µL) during RT. A low ALC nadir during RT was significantly associated with poor OS, PFS, and LRFS. The planning target volume (PTV) was larger in patients with low ALC nadir compared with patients with high ALC nadir (418.5 vs. 347.7 cm 3 , P = 0.023). Multivariate logistic regression analysis revealed that tumor stage III-IVA (P = 0.002), low ALC before treatment (P = 0.028), large Log 10 (PTV) (P = 0.01), high heart V10 (P = 0.003), and high heart V20 (P = 0.028) were associated with low ALC nadir during RT. Conclusions: In ESCC patients who received definitive RT, a low ALC nadir during RT was associated with large PTVs, and it was an independent prognostic factor of outcomes.

Abstract-Particle Swarm Optimization algorithm (PSO) is a popular stochastic searching optimization algorithm to solve complicated optimization problems. The approach of retrieving duct parameters from the sea-surface reflected radar clutter is also known as Refractivity From Clutter (RFC) technique. RFC technique provides the near-real-time duct parameters to evaluate the radio system performance, without adding any hardware. Basic principles of PSO and its applications and RFC technique are introduced. Evaporation duct is retrieved based on RFC technique using PSO. The performance of PSO is validated using experiment data launched at East China Sea and compared with those of genetic algorithm (GA) and ant colony algorithm (ACA). The results indicate that PSO has the advantages of faster convergence and higher retrieval precision than the other two methods.

Radiotherapy is a frequently utilized therapeutic modality in the treatment of esophageal cancer (EC). Even though extensive studies are carried out in radiotherapy for EC, the design of the clinical target volume and the radiation dose is not satisfactorily uniform. Radiotherapy acts as a double-edged sword on the immune system; it has both an immunostimulatory effect and an immunosuppressive effect. Radiation-induced lymphopenia and its potential association with tumor control and survival outcomes remain to be understood. The advent of immunotherapy has renewed the focus on preserving a pool of functioning lymphocytes in the circulation. In this review, we summarize the potential impact mechanisms of radiotherapy on peripheral blood lymphocytes and the prognostic role of radiation-induced lymphopenia in patients with EC. We also propose the concept of organs-at-risk of lymphopenia and discuss potential strategies to mitigate its effects on patients with EC. From an immunological perspective, we put forward the hypothesis that optimizing radiation modalities, radiation target volume schemes, and radiation doses could help to reduce radiation-induced lymphopenia risks and maximize the immunomodulatory role of radiotherapy. An optimized radiotherapy plan may further enhance the feasibility and effectiveness of combining immunotherapy with radiotherapy for EC.