Lymphopenia after Radiotherapy and Risk of Infection. (4th October 2017)

• Record Type: Journal Article
• Authors: Terrones, Cynthia; Specht, Lena; Maraldo, Maja V; Lundgren, Jens; Helleberg, Marie
• Is Part Of: Open forum infectious diseases. Volume 4(2017)Supplement 1
• Page Start: S702
• Page End: S702
• Publication Date: 2017-10-04
• Subjects: Communicable diseases -- Periodicals; Medical microbiology -- Periodicals; Infection -- Periodicals; 616.9
• DOI: 10.1093/ofid/ofx163.1882
• Languages: English
• ISSNs: 2328-8957

Abstract

Abstract: Background: Radiotherapy may cause lymphocyte depletion; although extent, duration, and possible associated excess risk of infection from lymphopenia are unknown. These questions were addressed in a recently established cohort of consecutive cancer patients undergoing radiotherapy and with complete long-term nation-wide follow-up. Methods: The cohort constitutes patients who received first course of radiotherapy in the period 2005–2016 at Copenhagen University Hospital. Lymphocyte counts at radiotherapy start and at 1, 6, 12 and 24 months thereafter allowed for classifying those with lymphopenia (<1.0 × 10 3 cells/µL). Whether this condition was associated with excess risk of subsequent first hospital admission with a diagnosis of infection was assessed by Poisson regression analysis, adjusted for age, sex, and calendar year. Results: During the study period 22, 151 patients had a first course of radiotherapy, of whom 14, 823 had a lymphocyte count, measured in at least one of the pre-defined time points. Median duration of radiotherapy was 28 days (IQR, 12–39). Lymphocyte counts declined in the first month after initiation of radiotherapy then increased gradually during follow-up. At month 24, 28.6% of cohort in follow-up had lymphopenia (Figure 1). During 39, 620 per 1, 000 person-years of follow-up, 3, 644 (24.6%) patients had a hospital admission with an infection; most frequently a respiratory infection (48.2%), followed by urinary tract (13.8%) and gastrointestinal infections (8.5%). Lymphopenia at 0, 6, 12 and 24 months after radiotherapy start, but not at month 1, was associated with increased risk of subsequent admission with infection (Table 1). Conclusion: The majority of cancer patients develop lymphopenia after radiotherapy, which persist in a fraction of the population for several months. Radiotherapy-associated lymphopenia was associated with increased risk of subsequent hospital admission with an infection, suggesting clinically relevant impairment of immune function in a subgroup of the treated population. Disclosures: All authors: No reported disclosures.