Air Transfer of Patients with Newly Diagnosed Acute Myeloid Leukemia: The Experience of French Polynesia

Introduction Acute myeloid leukemia (AML) is a rare and rapidly life-threatening disease without treatment. Patients require rapid and complex treatment. French Polynesia is a French archipelago in the South Pacific, 16,000 km (or 10,000 miles) from mainland France, comprising 118 islands. Since 2010, Polynesian AML patients eligible for intensive treatment have been flown to Saint-Antoine Hospital in Paris immediately after diagnosis. The commercial flight takes around 18 hours, with a two-hour technical stopover in North America. An on-site hematologist selects patients based on age, comorbidities, performance status and disease characteristics. The transfer is supervised by a physician traveling with the patient and able to assist him/her. This study aims to describe patient characteristics and evaluate the safety and outcomes of this singular process.

Patients & Methods In this retrospective study, we consecutively included all patients over 18 years of age with newly diagnosed AML at the Centre Hospitalier de la Polynésie Française in Tahiti (French Polynesia) between 01/01/2010 and 04/30/2021, who were then transferred to Paris for intensive treatment. Patients with acute promyelocytic leukemia or in relapse were not included. Clinical information, treatment regimen and response, as well as clinical outcome data were collected.

Results During the study period, 52 newly diagnosed and transferred patients were identified from a total of 142 AML diagnoses during this period (Table 1). The median age at diagnosis was 51.8 years (range, 18-74.4), and 37% were women. Forty-four patients had de novo AML and 8 (15%) had secondary AML. The white blood cell (WBC) count at diagnosis was 121 G/L (range, 0.8-352), and the WBC count on arrival in Paris was 28.5 G/L (range, 0.7-106). Forty-one patients (79%) received hydroxyurea-based cytoreductive therapy during the transfer. During the flight 27 patients (53%, data missing for one patient) received broad-spectrum antibiotic therapy and 5 patients received nasal cannula oxygen during transfer (10%, data missing for 2 patients). One patient aged 35 years could not be transferred due to uncontrolled hyperleukocytosis and received induction therapy on site prior to transfer. Four patients (7.7%) were admitted to intensive care on arrival in Paris. The median time from diagnosis to arrival in Paris was 7 days (range, 2-60), and the median time from diagnosis to induction therapy was 11.5 days (range, 2-66). One patient died within 30 days of induction. According to European LeukemiaNet (ELN) 2022, the genetic risk was distributed as follows: favorable n=15 (29%), intermediate n=16 (31%) and adverse n=17 (33%); data were missing for 4 patients. All patients received intensive treatment with cytarabine and anthracycline, except for three who received hypomethylating agents (6%). Thirty-four patients (65%) achieved complete remission after the first treatment cycle. Eighteen patients (35%) underwent allogeneic stem cell transplantation. The median duration of the first stay in France was 8 months (range, 2-40.3). The 2-year survival rate was 68% (95% CI, 59.3-83.9) and the 5-year survival rate was 50% (95% CI, 35.2-63.2). The median follow-up was 56.1 months (range, 0.3-146.6).

Conclusions This study confirms the feasibility of transferring selected adult patients with AML diagnosed in French Polynesia by air to a specialized center. The long duration of transfer in these patients does not appear to negatively affect prognosis, with early mortality, 2-year and 5-year survival comparable to that observed in historical cohorts. Our approach could be extended to other isolated areas where there is no highly specialized center for the treatment of AML patients.