2025 Southeastern Residency Conference

Title: A Review of the Incidence of Pneumocystis Pneumonia Infection with or without Pneumocystis Pneumonia Prophylaxis in Patients with Brain Tumors 


Authors: Gabrielle McCammack, Marley Watson, Danielle Rustem, Brooke Rowling, Benjamin Albrecht, Kimberly Hoang, Manali Rupji, Xiyuan Ji, Jeffrey Switchenko


Background: Temozolomide is an oral alkylating agent administered with radiation for high-grade gliomas. According to the temozolomide drug monograph, patients should receive prophylaxis against Pneumocystis pneumonia (PCP) while receiving concurrent chemotherapy and radiation treatment. However, the Infectious Diseases Society of America recommends prophylactic antibiotics in chemotherapy regimens with less than 3.5% risk of contracting PCP. There are many suspected risks factors for development of PCP, yet recent studies have shown the incidence of PCP infection in this patient population is low, less than 1%. In addition, prophylactic antibiotics for PCP are associated with side effects and additional costs for patients. The decision to prescribe PCP prophylaxis for patients at Emory Healthcare is provider specific. The purpose of this study is to determine the incidence of PCP development with or without PCP prophylaxis and evaluate possible risk factors correlating with PCP development. 

Methods: This is a retrospective chart review of adult patients with brain tumors treated with concurrent phase temozolomide with radiation therapy at Emory Healthcare. Patients with high grade gliomas on concurrent temozolomide with radiation therapy will be included and will be categorized based on use of prophylactic antibiotics for PCP. Patients will be excluded for use of prophylactic antibiotics with activity against PCP for another indication, having reduced radiation courses, starting PCP prophylaxis after one week of chemotherapy treatment, or having insufficient documentation to confirm chemotherapy cycles. The primary outcome is to determine the incidence of PCP development with or without PCP prophylaxis, with safety as a secondary outcome. Descriptive statistics using mean and standard deviations for numerical variables and frequency and percentages for categorical clinicopathological variables. 

Results: A total of 67 patients were included in the study, 20 received PCP prophylaxis, 47 did not receive PCP prophylaxis. The mean age of patients was 54 years old in the prophylaxis group, and 55 in the without prophylaxis group. Most patients were on high dose steroids (prednisone equivalents > 20mg daily) for 1 month prior to treatment; 15 (75%) in the with prophylaxis group and 38 (80.9%) in the without prophylaxis group. Three patients in the without prophylaxis group had an immunocompromising condition at baseline; with 2 (4.3%) patients on hydroxychloroquine and 1 (2.1%) patient on infliximab. For patients on PCP prophylaxis, 9 (45%) were on trimethoprim/sulfamethoxazole, 10 (50%) inhaled pentamidine, and 1 (5%) on atovaquone. No patients developed a PCP infection; therefore, an analysis was not performed.

Conclusion: No cases of PCP were found for patients on treatment or 90 days post treatment in either the with or without prophylaxis groups. No events occurred despite 79.1% and 4.5% of the patient population being on high dose steroids or immunocompromising medications, respectively. Though some patients had a reduction in ALC while on treatment, more data is needed to determine if this is a true risk factor for development of PCP infection. Larger studies are needed to further assess and define risk factors for developing PCP infection while on concurrent temozolomide and radiation treatment and ultimately create a risk stratification tool that can better identify patients requiring PCP prophylaxis to minimize additional medication use and side effects.