Severe Treatment-Related Lymphopenia in Patients with Newly Diagnosed Rectal Cancer

Background: Although treatment-related lymphopenia (TRL) is common in many cancers no data exists in rectal cancer. Methods: Serial lymphocyte counts were analyzed retrospectively in patients with newly diagnosed rectal cancer, serial blood counts, and complete records at Johns Hopkins Hospital. Results: Fifty-seven patients with normal pretreatment lymphocyte counts were studied. Two months after beginning chemoradiation, 35% of these patients developed grade III-IV lymphopenia [median lymphocyte counts fell from 1590 to 490 cell/mm³ (p < 0.001)] which persisted throughout one year of observation. Conclusion: Severe and prolonged TRL is common in rectal cancer. Further studies are required to determine TRL’s relationship to survival.