Esophageal cancer is the seventh most common type of cancer in the world, with the World Cancer Research Fund estimating 572,000+ cases diagnosed in 2018.1 Half of these cases occur in a region stretching from Central Asia to China known as the “esophageal cancer belt.”2 Immunotherapy research relating to potential treatment to improve survival is of great interest in China.
Researchers at Tianjin Medical University Cancer Institute and Hospital, the oldest and largest cancer treatment center in China, recently reported in the February issue of Frontiers in Oncology that concurrent immune therapy and radiation therapy may promote anti-tumor immune response in patients with esophageal squamous cell carcinoma. They measured radiation-therapy induced changes in peripheral blood lymphocyte (PBL) subpopulations and evaluated the prognostic value of lymphocyte alterations.3
The study included 64 patients who received either neoadjuvant chemoradiotherapy followed by radical surgery or definitive chemoradiotherapy. The 54 patients who did not have surgery were prescribed a dose of 60 Gy in 30 fractions; for those who had surgery, a dose of 40 Gy in 20 fractions was prescribed. The patients were predominantly male (88%), had a smoking history (70%), and all but 8 percent had advanced disease (stage III = 70%; stage IVa = 22%). Sixty-one patients completed the prescribed radiation therapy regimen.
The researchers collected blood samples at baseline and during treatment. Chemoradiotherapy-induced alterations were identified for all cases of circulating lymphocyte subpopulations. They determined that the proportion of CD19+B cells decreased the most markedly following radiation, from 7.5% to 2.9%, and that the mean absolute lymphocyte counts decreased from a baseline of 3,081 to 2,445. Patients with both increased CD4+ and CD8+ ratios experienced superior progression-free survival and overall survival during a median follow-up of nearly a year.
“Our study showed that concurrent chemoradiotherapy can activate the immune system and that CD4+ and CD8+ T-cells are positively associated with the superior progression-free survival and prolonged survival,” wrote lead author Xi Chen, of the Department of Radiation Oncology. The progression-free survival rate at one year was 63% for patients with increased CD4+ and CD8+ ratios compared to 25% for the other patients; one-year overall survival was 80% vs 62%, respectively.
The research showed that chemoradiotherapy-induced increases in peripheral CD4+ and CD8+ T-cell levels are a surrogate marker for immunostimulation, according to the authors. They wrote that patients who had both increased CD4+ and CD8+ ratios had a remarkably better prognosis, which was consistent with the “well-established cooperative role of CD4+ and CD8+ T-cells in tumor eradication.”
Based on their research, the authors believe that immune therapy may promote anti-tumor immune response and confer a survival benefit to patients with esophageal squamous cell carcinoma.
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Study: Radioimmunotherapy for esophageal cancer may boost anti-tumor immune response and survival benefit . Appl Rad Oncol.