Does the Occurrence of Invasive Fungal Infection in Acute Leukemia Patients, Impact on the Chemotherapy Schedule and Event-Free Survival? a Case-Control Study

Background: In acute leukemia (AL) patients, mortality rates of the most common IFI (i.e., aspergillosis and candidiasis) are well illustrated in the literature from the IFI diagnosis, as well as the rate of fungal relapse during subsequent periods at risk, such as neutropenic phases, or transplant. However, few data are available about the impact of IFI on the subsequent chemotherapy schedule and the indirect impact of IFI on the relapse-free and overall survival. Clinicians are usually reluctant to give the full chemotherapy doses on time, due to the risk of life-threatening fungal relapse during the subsequent courses. Even with secondary prophylaxis, they often delay or decrease the doses of chemotherapy. This may impact on the leukemia outcome. The aim of this case-control study was to assess the potential impact of proven or probable IFI onset on the application of the chemotherapy schedule in AL patients, and its consequences on the leukemia outcome, by comparing patients with and without IFI in a single institution. Delays and changes in chemotherapy doses and drug choices were evaluated and compared to the planned schedule in the protocol.

Methods: All consecutive AL patients with a first episode of proven or probable IFI according to the EORTC-MSG criteria between 2000–2006 were reviewed. All patients have been treated in, or according to, clinical research protocols where timing and doses of chemotherapy were predefined. Patients who were planned for allogeneic transplant were excluded as those who were at their last consolidation course when they got IFI or in a palliative phase of the leukemia. Any delay, dose decrease, or dose change were defined as any difference compared to the planned schedule. We planned to include 3 control patients for each case, selected among AL patients without IFI, and matched for age, sex, type of AL, chemotherapy protocol, and year of treatment. 27 case and 76 control patients were finally included. The event-free survival (EFS) was defined as survival without evidence of relapse or progression, or death of any cause.

Results: The mean age of the 27 case patients (26 myeloid and 1 lymphoblastic AL) was 52 y (± 13), the M/F ratio was 14/13 IFI (7 candidiasis, 19 aspergillosis, 1 zygomycosis) was proven for 10 patients (37%), and probable for 17 (63%). Twenty (71%) of these IFI occurred during the first induction phase. All patients were treated for their IFI with ≥ 1 antifungal, and 4 of them had a surgical resection of the main fungal lesion(s). These 27 patients were compared to 76 controls (73 myeloid and 3 lymphoblastic AL) without IFI. A delay of the next course of chemotherapy according to the planned protocol was significantly more frequent in the IFI group (16/27, 59%) than in the control group (16/76, 21%) (p=.001). Similarly, the dose or choice of the drugs was modified more frequently in the IFI group (7/27, 26%) than in the control group (6/76, 8%) (p=.037). Only 9 (33%) patients got their next chemotherapy course without any modification in time, dose, or choice of drug, vs. 19/76 (75%) in the control group (p<.0001). The EFS of the IFI group was lower than that of the control group, although this difference was not significant.

Conclusion: In this single-institution case-control study, the occurrence of IFI significantly modified the application of chemotherapy courses, both on timing of the courses, and dose and choice of the drugs when compared to patients without IFI. Although the difference was not significant, there was a tendency for a lower EFS in the IFI group when compared to the control group.⁻