Patient Characteristics and Distribution of IDRF
Among the 72 patients included in the analysis, 37 were female and 35 were male before treatment. Patient characteristics are shown in Table 1. The distribution of the INRG stages was 10 L1 (13.9.0%), 25 L2 (34.7%), and 37 M/MS (51.4%). A total of 182 IDRF at diagnosis were found in 57/72 (79.2%) patients, and the maximum number of IDRF in a single patient was 9 (n = 1) and the median number of IDRF was 2 [1–4 ]. Of the 25 patients in stage L2, 17 (68.0%) had IDRF numbers ranged one to three and 17 (32.0%) had greater than four number of IDRF. Among the 37 patients with stage M/MS, 5 (13.5%) patients (8%) had no IDRF, 17 (46.0%) had an IDRF number ranged one to three, and 15 (40.5%) had greater than four IDRF (Table 2).
Table 1
Clinical and biological features according to INRG stages in patients with neuroblastoma.
Feature | All Patients No. (%) | Stage L1 No. (%) | Stage L2 No. (%) | Stage M/MS No. (%) | P-value |
Clinical features | | | | | |
Male Female | 35(48.6) 37(51.4) | 5(50) 5(50) | 15(60) 10(40) | 15(40.5) 22(59.5) | 0.319 |
Age ≥ 18 mo at diagnosis Age < 18 mo at diagnosis | 49(68.1) 23(31.9) | 4(40) 6(60) | 15(60) 10(40) | 30(81.1) 7(18.9) | 0.026 0.017* |
Tumor volume (cm3 = ml) | 127.2 [44.4,326.2] | 22.8 [13.6,164.4] | 119.8 [56.1,301.8] | 195.8 [63.4,481.6] | 0.025 0.042* |
IDRF number | 2[1, 4] | - | 2[1, 4] | 3[1, 4] | 0.023 |
With calcification No calcification | 59(81.9) 13(18.1) | 7(70) 3(30) | 20(80) 5(20) | 32(86.5) 5(13.5) | 0.399 |
High risk Low/intermediate risk | 40(68.8) 28(41.2) | 3(30.0) 7(70) | 5(23.8) 16(76.2) | 32(86.5) 5(13.5) | < 0.001 0.001* < 0.001& |
High LDH (≥ 750 U/l) Normal LDH (< 750 U/L) | 40(55.6) 32(44.4) | 2(20) 8(80) | 12(48) 13(52) | 26(70.3) 11(29.7) | 0.014 0.009* |
High ferritin (≥ 120ng/mL) Normal ferritin (< 120ng/mL) | 35(54.7) 29(45.3) | 3(37.5) 5(62.5) | 7(31.8) 15(68.2) | 25(73.5) 9(26.5) | 0.005 0.003& |
Direct resection Surgery after neoadjuvant | 29(40.3) 43(59.7) | 9(90) 1(10) | 11(44) 14(56) | 9(24.3) 28(75.7) | 0.001 0.022# < 0.001* |
Biological features | | | | | |
Unfavorable histology Favorable histology | 36(62.1) 22(37.9) | 6(75) 2(25) | 9(45) 11(55) | 21(70) 9(30) | 0.149 |
Undifferentiated/poorlyDifferentiated Differentiating | 32(71.1) 13(28.9) | 4(80) 1(20) | 9(60) 6(40) | 19(76.0) 6(24.0) | 0.506 |
MYCN amplified MYCN non-amplified | 11(15.9) 58(84.1) | 0(0) 10(100) | 2(8.0) 23(92) | 9(26.5) 25(73.5) | 0.06 |
*, Stage L1 vs. Stage M/Ms; &, Stage L2 vs. Stage M/Ms; #, Stage L1 vs. Stage L2; INRG, International Neuroblastoma Risk Group; IDRF, image defined risk factors; LDH, lactate dehydrogenase. |
Table 2
Distribution of IDRF number and type in patients with neuroblastoma.
IDRF number | All Patients No. (%) | Stage L1 No. (%) | Stage L2 No. (%) | Stage M/MS No. (%) |
0 | 15(20.8) | 10(100) | - | 5(13.5) |
1–3 | 34(47.2) | - | 17(68) | 17(45.9) |
≥ 4 | 23(32.0) | - | 8(32) | 15(40.5) |
IDRF type | | | | |
Vascular IDRF | 53(73.6) | - | 22(88.0) | 31(83.8) |
Infiltrative IDRF | 26(36.1) | - | 8(32.0) | 18(48.6) |
Extensive IDRF | 15(20.8) | - | 8(32.0) | 7(18.9) |
Neurological IDRF | 12(16.7) | - | 8(32.0) | 4(10.8) |
Airway compression | 1(1.4) | - | 1(4.0) | 0(0.0) |
IDRF, image defined risk factors. |
Data on IDRF type showed that 53 (73.6%) patients had a total of 123 vascular IDRF, 26 (36.1%) patients had a total of 31 infiltrative IDRF, 15 (20.8%) patients had extensive IDRF, 12 (16.7%) patients had neurological IDRF, and only one patient had airway compression. The distribution of the IDRF type in the INRG stages is shown in Table 2.
Clinical And Biological Features Related To Inrg Stages
Clinical features were found to be significantly associated with INRG stages in the full cohort (Table 1). We observed significant trends for an increasing percentage of patients with unfavorable clinical features with increasing tumor stage. Patients with stage M/Ms had larger tumor volume (P = 0.025), a higher percentage of patients aged ≥ 18 months ( 81.1% for stage M/Ms, 60.0% for stage L2, and 40.0% for stage L1; P = 0.026), elevated LDH levels (70.3% for stage M/Ms, 48.0% for stage L2, and 20.0% for stage L1; P = 0.026), and elevated ferritin levels (73.5% for stage M/Ms, 31.8% for stage L2, and 37.5% for stage L1; P = 0.005) compared with stage L1 and L2 patients. In addition, a prominent difference in the COG high risk between stage M/Ms disease and other stages (86.5% for stage M/Ms VS 23.8% for stage L2, P < 0.001; 86.5% for stage M/Ms VS 30.0% for stage L1, P = 0.001) was observed. As for the treatment modality, tumors without IDRF and stage L1 patients achieved more direct surgical resection compared with other stage patients (90.0% for stage L1 vs 44.0% for stage L2, P = 0.022; 90% for stage L1 vs 24.3% for stage M/Ms, P < 0.001).
Fewer associations between unfavorable biological features and INRG stages were detected in the full cohort, including unfavorable histology, undifferentiated/poorly differentiated grades, and MYCN amplification (Table 1). We observed an increase in the percentage of MYCN amplified in stage M/Ms compared with non-stage M/Ms patients (26.5% for stage M/Ms, 8.0% for stage L2, and 0% for stage L1, P = 0.06).
Clinical Outcomes Related To Inrg Stage
During the study period, 27 children (37.5% of 72) experienced an event and 19 children (26.4% of 72) died. Kaplan-Meier analysis revealed that the EFS and OS were similar for stage L1 and L2 tumors but were significantly poorer for metastatic disease (Fig. 1). Specifically, in 37 patients with stage M/M, EFS and OS were significantly lower than patients in stage L2 (EFS: X2 = 10.88, P = 0.001; OS: X2 = 12.78, P < 0.001) and patients in stage L21 (EFS: X2 = 9.033, P = 0.003; OS: X2 = 6.88, P = 0.01).
In the full cohort, IDRF-negative patients remained prognostic of higher EFS (X2 = 3.45, P = 0.06) and OS (X2 = 3.07, P = 0.07) than IDRF-positive patients, but the difference was not significant (X2 = 5.743, P = 0.017). Similarly, IDRF-negative patients also did not have significantly better EFS (X2 = 0.184, P = 0.668) and OS (X2 = 0.826, P = 0.363) than IDRF-positive in M/Ms patients. Therefore, a subgroup analysis of the outcomes between IDRF-positive tumors with and without metastatic disease was conducted. Patients with stage M/Ms with IDRF-positive had poorer EFS (X2 = 11.242, P = 0.001) and OS (X2 = 14.003, P < 0.001) than patients with stage L2 disease (Fig. 2).
Clinical Outcomes Related To Idrf Number And Type
In the full cohort, we observed that patients with IDRF ≥ 4 had poorer EFS (X2 = 5.743, P = 0.017) and OS (X2 = 6.478, P = 0.011) than patients with IDRF < 4 (Fig. 3). However, in both stage L2 and M/Ms patients, no significant differences in EFS and OS were identified between IDRF ≥ 4 and IDRF < 4 (all P > 0.05).
Regarding specific IDRF type, tumors with vascular IDRF had lower EFS (X2 = 6.666, P = 0.010) and OS (X2 = 5.180, P = 0.023) compared to tumors without vascular IDRF; tumors with infiltrative IDRF had lower EFS (X2 = 7.527, P = 0.006) compared to tumors without infiltrative IDRF; similar results were also found in OS but were not significant (X2 = 3.034, P = 0.082) (Fig. 3); However, other IDRF types, including neurological IDRF, extensive IDRF, and airway compression, were not associated with EFS and OS (all P > 0.05).