Clinical Outcomes of Patients With Newly Diagnosed Acute Lymphoblastic Leukemia in a County Hospital System

Abstract

Background: Major advances in the treatment of acute lymphoblastic leukemia (ALL) over the past decade have resulted in 5-year overall survival (OS) rates of 80% in mature B cell ALL, 50% in precursor B cell ALL, 50% to 60% in T cell ALL, and 60% to 70% in Philadelphia chromosome-positive (Ph+) ALL, as reported in studies from large, specialized centers. However, many patients treated in the community have limited access to novel therapies and stem cell transplantation (HSCT).

Patients and methods: The purpose of this retrospective cohort analysis was to evaluate the clinical outcomes of patients ≥ 16 years with newly diagnosed ALL treated from October 2007 to June 2019 in the Harris County Health System, Houston, TX.

Results: One hundred forty-six patients were included, with newly diagnosed pre-B-ALL (n = 127), T-ALL (n = 18), and chronic myeloid leukemia and/or lymphoid blast crisis (n = 1). Median age was 35 years (16-82) at diagnosis, and 81(55%) were male. The majority of patients with pre-B ALL identified as Hispanic (n = 118, or 92%). Ninety-eight (67%) of patients were uninsured or indigent, receiving care under the county's financial assistance programs. Hyper-CVAD-based induction chemotherapy was administered in 134 (92%) of patients, while 9 (6%) were treated on different protocols, and 3 (2%) were not treated due to early death, or patient refusal. Imatinib was the most common TKI used in 17 of 30 or 57% of patients with Ph+ disease. Out of 137 evaluable for response patients, 117 (85%) achieved complete remission (CR + CRi), 19 (14%) had refractory disease, and 1 (1%) died within 4 weeks of diagnosis. Median follow-up time was 50 months (1.5-135). For the entire study cohort, the median duration of CR/CRi was 15.4 months. Out of 62 patients who were eligible for consolidative HSCT at first CR, 52 (89%) did not receive it, with lack of insurance being the most common reason (n = 29, or 56%). Barriers to utilization of novel therapies such as blinatumomab or CAR-T were also observed. Patient-caused delays in administration of chemotherapy and treatment interruptions of at least 30 days were seen in 31(23%) patients. At 1, 2, and 5 years, relapse rates were 37%, 56%, and 70%. Recurrent and/or refractory disease was the cause of death in most patients (n = 69 [85%]). Five-year EFS and OS rates were 22% and 38% for patients with pre-B ALL, 24% and 44% for patients with T ALL, and 13% and 27% for patients with Ph+ ALL. Median OS was significantly increased (not reached [NR] vs. 24 months; P = .00088) in patients with an indication for HSCT in first CR due to high-risk features who underwent HSCT, versus those who did not.

Conclusion: Addressing barriers raised by socioeconomic disparities, increasing access to effective therapies, and including patients with ALL treated in the community in clinical trials may improve survival for underserved populations.

Keywords: Acute Lymphoblastic Leukemia; County Hospital System; Health Disparities; Retrospective study; Safety-net Hospital System.