To examine the superiority of PBT to photon-based RT in treating esophageal cancer patients, this systematic review included 23 original studies (1 randomized control study, 2 propensity matched analyses, and 20 cohort studies) for qualitative analysis. Overall survival and progression-free survival were better after PBT than after photon-based RT, but the difference was significant in only one of seven studies. The rate of grade 3 cardiopulmonary toxicities was lower after PBT (0-13%) than after photon-based RT (7.1-30.3%). Three of four reports evaluating the absolute lymphocyte counts (ALC) showed a significantly higher ALC after PBT than after photon-based RT.