A multicenter study of pandemic influenza A (H1N1) infection in patients with solid tumors in 3 countries: early therapy improves outcomes.

Background: Pandemic influenza A (hereafter 2009/H1N1) caused significant morbidity and mortality during the 2009 pandemia. Patients with chronic medical conditions and immunosuppressive diseases had a greater risk of complications. However, data regarding the characteristics and outcome of 2009/H1N1 infection in patients with solid tumors are nonexistent. Herein, the authors describe a series of influenza 2009/H1N1 in patients with solid malignancies at 3 major cancer hospitals worldwide.

Methods: The authors retrospectively reviewed the records of patients with solid organ malignancies and 2009/H1N1 from The University of Texas M. D. Anderson Cancer Center in Houston, Texas; the Mexican National Cancer Institute, Federal District of Mexico; and King Hussein Cancer Center in Amman, Jordan from the period of the 2009 H1N1 pandemia. Data on demographics, disease characteristics, and outcome were extracted.

Results: In total, 115 cases were identified during the pandemic influenza among the 3 institutions. High rates of hospitalization (50%), pneumonia (23%), and death (9.5%) were reported. Patients who developed pneumonia and those who died were moderately to severely immunocompromised (P = .001 and P = .006, respectively). A multivariate competing risk analysis demonstrated that a delay >48 hours in starting antiviral therapy was associated significantly with an increased risk of developing pneumonia (P = .013).

Conclusions: The 2009/H1N1 pandemic caused severe illness in immunocompromised patients with cancer who had solid tumors, and heavily immunosuppressed patients were at greater risk of developing pneumonia and death. Early initiation of antiviral therapy is crucial in this patient population to decrease morbidity and probably mortality.