Pneumocystis infection during first-line chemotherapy for solid tumours: Increased virulence or better diagnosis?

Abstract

e18277 Background: Pneumocystis Jirovecii (PJP, previously Pneumocystis Carinii) infection is typically seen in those with advanced immunodeficiency such as Acquired Immunodeficiency Syndrome, haematological malignancies, sustained chemotherapy with temozolomide or patients heavily pretreated with multiple lines of chemotherapy. PJP rarely presents early in the natural history of solid tumour malignancy. We observed a cluster of cases of PJP at our institution in patients undergoing first-line chemotherapy for solid tumours. Methods: An electronic database search was conducted to identify occurrences of PJP over a 3 month period. 4 patients were identified who developed Pneumocystis Jirovecii. The patients’ records, laboratory, radiology and pathology results were examined. Results: All 4 patients identified had developed PJP during first line chemotherapy for GI malignancy. In each case, the patient presented with dyspnoea, fever and hypoxia. All were noted to be lymphopenic with lymphocyte counts of 0.2 to 0.9 x10^9/L. All were HIV negative. Chest CT revealed new bilateral ground-glass changes associated with cyst formation. All cases were found to have positive PJP PCR on testing of induced sputum. On the basis of clinical presentation, positive PCR sputum cultures and CT findings, the patients were diagnosed with PJP and treated with high-dose sulphamethoxazole and trimethoprim. 3 patients recovered and 1 died despite best ICU management. Conclusions: The relatively high number of cases of PJP early in treatment is noteworthy. It raises the question as to whether PJP is becoming more potent or that better awareness leads to earlier and more accurate diagnosis. Coincidental clustering is also a possibility. Clinicians should be aware that pneumocystis infection can occur during first-line therapy in solid tumour malignancy. It should be considered as a differential in any patient on chemotherapy (regardless of line of therapy) presenting with acute respiratory illness.