Patients’ characteristics
From 2013 to 2022, 24 patients diagnosed with de novo Acute Promyelocytic Leukemia (APL) were enrolled in our center of the Oncohematology Department of the National Cancer Institute Bratislava, Slovakia. The demographic and clinical characteristics of the patients are summarized in Table 1. Ten patients (41.67%) were male and 14 (58.33%) were female. The ages of the patients ranged from 27 to 77 years, with a median age of 50 years. The median age of male patients was 36 years (range, 29–74 years), while that of female patients was 61 years (range, 27–77 years). Of the total patient cohort, 5 individuals (20.83%) were identified as having secondary APL. Regarding risk stratification, five patients (20.83%) were classified as high risk, while the remaining 19 patients (79.17%) were categorized as standard risk.
Table 1
Patient’s characteristics
Parameter (N = 24) | No (min-max) or (%) |
Age | 50 (27–77) |
Median age men 36 (29–74), women 61 (27–77) |
Sex | |
M | 10 (41.67%) |
F | 14 (58.33%) |
Secondary APL | 5 (20.83%) |
Risk stratification | |
High risk | 5 (20.83%) |
Standard risk | 19 (79.17%) |
Induction therapy | |
Group 1 ATRA/ATO standard risk | 16 (66.67%) |
Group 2 ATRA/CHT high risk | 5 (20.83%) |
Group 3 ATRA/CHT standard risk | 3 (12.50%) |
For induction therapy, patients were divided into three groups based on the treatment protocols:
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Group 1 (ATRA/ATO standard risk): 16 patients (66.67%).
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Group 2 (ATRA/CHT high-risk): 5 patients (20.83%)
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Group 3 (ATRA/CHT standard risk): 3 patients (12.50%)
Notably, Groups 2 and 3 served as control cohorts.
All patients with standard-risk APL achieved molecular remission after induction; in the high-risk group, 1 patient died of cardiac failure within the differentiation syndrome. The incidence of DS did not significantly differ among the treatment groups (7, 2 and 1 patients), with rates of 33.3%, 40.0%, and 43.8% in ATRA/CHT SR, ATRA/CHT HR, and ATRA/ATO SR groups respectively (p = 0.7697), however, there was trend towards higher incidence in ATRA/ATO SR group. Leukocyte peak values showed a trend towards significance, with ATRA/ATO SR group having higher peak levels of 34.5 (6.0-113.4) G/L compared to ATRA/CHT SR - peak of leukocytes 7.8 (4.4–13.3) and ATRA/CHT HR - peak of leukocytes 33.6 (25.6–47.1) G/L groups (p = 0.0809). The time taken to achieve differentiation syndrome (DS) varied slightly across the groups. ATRA/CHT SR had a median time of 4 days (p = 0.3520), ATRA/CHT HR had a median time of 3 days, and ATRA/ATO SR had a median time of 4 days from ATRA initiation and 2 days from ATO initiation. Most ATRA/ATO patients started to differentiate 1–2 days after ATO initiation.
The examination of DS symptoms, as outlined by the Montesinos criteria, was performed in the context of different treatment modalities. Within the groups, patients undergoing ATRA/ATO SR treatment displayed a notably higher occurrence of weight gain exceeding 5 kg (9 patients, 56.3%), peripheral edema (8 patients, 50.0%), dyspnea (9 patients, 56.3%), and fever (4 patients, 25.0%). However, these results were not statistically significant.
Table 2 summarizes the alanine aminotransferase (ALT) values at D1-10 time points during induction across the three groups. Patients in the ATRA/ATO group exhibited higher ALT levels on day 7 (D7), although the difference was not statistically significant. However, by Day 10 (D10), the difference was statistically significant (p = 0.0373), indicating an association between treatment modality and hepatic impairment, especially at later time points. ALT elevation was significantly more prevalent in the ATRA/ATO SR group (15 patients, 93.75%) than in the ATRA/CHT SR (3 patients, 66.7%) and ATRA/CHT HR (3 patients, 60.0%) groups (p = 0.0129). This number was higher than that reported in previous studies. Notably, eleven (68.75%) of ATRA/ATO SR patients experienced grade 3–4 ALT elevation compared to none in the ATRA/CHT SR and ATRA/CHT HR groups (p = 0.0094). We also observed that some patients in the chemotherapy group exhibited elevated ALT levels during the induction phase, albeit to a lesser degree. All 15 patients with ALT elevation had elevated ALT during episodes of DS symptoms or leukocytosis (15/15, 100%), and all had ALT levels approximately normal (≤ 2N) during consequent consolidation therapies.
Table 2
ALT values during induction vs group
| ATRA/ATO SR | ATRA/CHT HR | ATRA/CHT SR | p |
ALT D1+ | 0.74 (0.17–1.78) | 1.06 (0.36–2.12) | 0.54 (0.56–0.80) | 0.2409 |
ALT D5+ | 1.23 (0.23–6.06) | 1.26 (0.36–2.52) | 0.77 (0.80–1.01) | 0.6242 |
ALT D7+ | 2.32 (0.26–7.99) | 1.25 (0.36–2.71) | 0.77 (0.80–1.01) | 0.2207 |
ALT D10+ | 3.59 (0.38–13.30) | 0.94 (0.27–1.52) | 1.15 (0.66–1.80) | 0.0373* |
ALT elevated | 15 (93.75%) | 3 (60.0%) | 2 (66.7%) | 0.0129* |
G3-4 | 11 (68.75%) | 0 | 0 | 0.0094* |
Table 3 compares the initial values of ALT, Le, and LDH with respect to the severity of hepatic impairment (graded as G3-4 and G0-2) during induction in the ATO/ATRA group. Higher initial values of ALT (0.81 vs. 0.26) and LDH (5.25 vs. 3.31) were associated with a greater severity of hepatic impairment (G3-4) and the results were statistically significant (p = 0.0108 and p = 0.0474, respectively).
Table 3
Initial values (D1) of ALT, Le, LDH, vs hepatic impairment (ALT elevated) during induction in ATO/ATRA group
| ALT elevated G3-4 | ALT elevated G0-2 | P |
ALT D1 | 0.81 (0.37–1.78) | 0.26 (0.17–0.8) | 0.0108* |
Le D1 | 2.25 (0.66–7.99) | 0.47 (0.42–7.01) | 0.0790 |
LDH D1 | 5.25 (3.7–6.96) | 3.31 (3.04–5.92) | 0.0474* |
The graphical representation in Fig. 1 illustrates the Group 1–3 mean values of leukocyte (Le), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels across different time points. Notably, the ATO/ATRA group exhibited distinctive patterns, particularly in comparison with their standard-risk chemotherapy counterparts. The ATO/ATRA group demonstrated a higher peak in leukocyte count, indicating a notable variation from their chemotherapy SR counterparts. In the ATO/ATRA group, ALT levels exhibited a peak around D8-11, showing a distinct temporal behavior, and the LDH levels in the ATO/ATRA group were consistently higher, suggesting a sustained difference from their chemotherapy SR counterparts. These observations underscored the unique dynamics of the ATO/ATRA group.
Figure 2 illustrates the diverse response patterns observed in patients undergoing ATRA/ATO treatment, categorizing them into three distinct groups based on the concurrent dynamics of leukocytes and ALT. LDH level indicates the amount of leukocyte turnover. A, B, C represent the laboratory parameters of a typical patient in each group.