Abstract
Background: Recent studies reported increased risk of Pneumocystis pneumonia (PCP) in patients treated with rituximab-containing chemotherapy and its incidence ranged from 2% up to 13%. However, there are no standard guidelines for PCP prophylaxis in patients with diffuse large B-cell lymphoma (DLBCL). Herein, we investigated the efficacy and safety of trimethoprim/sulfamethoxazole (TMP/SMX) as primary prophylaxis for PCP in patients with DLBCL treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP).
Method: We retrospectively review the patients with DLBCL who received R-CHOP every 21 days (R-CHOP-21) and received PCP prophylaxis with daily single-strength TMP/SMX (80mg/400mg) in Asan Medical Cencer, Seoul, Korea. We included patients only who completed at least 4 cycles of R-CHOP-21 and PCP prophylaxis. At first, we searched for patients with a positive test result for an immunofluorescence assay for PCP using bronchoalveolar lavage (BAL) samples. As a confirmative test of PCP, a direct immunofluorescence assay to detect P.jirovecii was performed with a commercially available kit (Light Diagnostics TM Pneumocystisjirovecii DFA Kit, Millipore, Billerica, MA, USA). Secondly, we searched for patients who received therapeutic doses of TMP/SMX for following clinical conditions; 1) symptoms such as fever, cough, or dyspnea, 2) radiologic findings compatible to PCP on chest X-ray or chest computed tomography, 3) no other definite cause of pneumonia.
Result: We identified 176 patients with DLBCL who received at least 4 cycles of R-CHOP-21 and concurrent PCP prophylaxis between June 2016 and December 2017. The median age was 59 (range, 22-84), 79 patients (44.8%) had advanced stage (stage III/IV) and 163 patients (92.6%) received 6 or 8 cycles of R-CHOP. The median follow-up duration of 13.6 months (range, 4.4 - 24), and TMP/SMX prophylaxis median cycles was 6 (range, 4-8). Among 176 patient, we identified 2 patients who had undergone bronchoscopy and the immunofluorescence assay for PCP using BAL samples in suspicious of PCP but no patients revealed positivity for the test. We also found that no patients received therapeutic doses of TMP/SMX during the chemotherapy. Grade 3/4 neutropenia and thrombocytopenia occurred in 30.6% and 8.1% of patients, respectively.
Conclusion: There was no PCP event in patients with DLBCL treated with R-CHOP-21 and TMP/SMX prophylaxis with daily single-strength TMP/SMX (80mg/400mg). Side effect profiles seems to be comparable with R-CHOP-21 alone.
No relevant conflicts of interest to declare.
