Table 1
(a) Risk (hazard) of dying in leukemia patients (1973–2006 SEER dataset) by age at diagnosis

Age at diagnosis (yrs)Alive No. (%)Dead No. (%)Incidence rate of dying per 1000 person-month

0375 (48.6)396 (51.4)9.86
1834 (71.0)340 (29.0)3.33
21468 (81.1)341 (18.9)1.77
31430 (82.7)300 (17.3)1.60
41099 (81.5)249 (18.5)1.87
5762 (78.4)210 (21.6)2.04
6544 (74.7)184 (25.3)2.44
7477 (72.9)177 (27.1)2.94
8406 (72.4)155 (27.6)2.86
10349 (69.0)157 (31.0)3.61
10320 (65.7)167 (34.3)4.05
11312 (64.9)169 (35.1)4.92
12325 (62.6)194 (37.4)5.12
13299 (57.9)217 (42.1)5.70
14330 (61.0)211 (39.0)5.82
15268 (51.6)251 (48.4)7.20
16293 (55.6)234 (44.4)6.20
17230 (48.7)242 (51.3)8.81
18196 (42.2)269 (57.8)10.22
19187 (43.0)248 (57.0)10.77

Abbreviation. SEER: Surveillance Epidemiology and End Results.
(b) Demographics and other study variables characterization by age group at diagnosis of pediatric patients with leukemia, SEER registry 1973–2006

CovariatesAge group at diagnosis (yrs)χ 2 (df) 𝑃 value
>11–45–910–1415–19

Sex49.7 (4)<0.0001
 Male386 (50.1)3411 (56.3)1871 (54.7)1450 (57.0)1504 (62.2)
 Female385 (49.9)2649 (43.7)1550 (45.3)1094 (43.0)914 (37.8)
Race52.2 (12)<0.0001
 White623 (80.8)5000 (82.5)2776 (81.1)2048 (80.5)1988 (82.2)
 Black71 (9.2)389 (6.4)283 (8.3)261 (10.3)208 (8.6)
 Others75 (9.7)651 (10.7)345 (10.1)223 (8.8)212 (8.8)
 Unknown2 (0.3)21 (0.3)17 (0.5)12 (0.5)10 (0.4)
No. of primaries57.9 (4)<0.0001
 1.0769 (99.7)6004 (99.1)3361 (98.2)2494 (98.0)2346 (97.0)
 ≥ 2.02 (0.3)57 (0.9)60 (1.8)50 (2.0)72 (3.0)
Cell type321.3 (4)<0.0001
 T-cell13 (7.3)168 (6.5)293 (19.6)244 (25.5)199 (25.3)
 B-cell, B-precursor166 (92.7)2407 (93.5)1199 (80.4)711 (74.5)588 (74.7)
Radiation 190.5 (4)<0.0001
 Yes90 (11.7)846 (14.0)581 (17.0)631 (24.8)517 (21.4)
 No681 (88.3)5215 (86.0)2840 (83.0)1913 (75.2)1901 (78.6)
Year of diagnosis61.8 (24)<0.0001
 1973–7747 (6.1)442 (7.3)268 (7.8)201 (7.9)213 (8.8)
 1978–8261 (7.9)430 (7.1)248 (7.2)206 (8.1)212 (8.8)
 1983–8768 (8.8)506 (8.3)271 (7.9)223 (8.8)193 (8.0)
 1988–9271 (9.2)649 (10.7)382 (11.2)213 (8.4)211 (8.7)
 1993–97109 (14.1)994 (16.4)519 (15.2)357 (14.0)316 (13.1)
 1998–02203 (23.3)1501 (24.8)903 (26.4)657 (25.8)623 (25.8)
 2003–06212 (27.5)1539 (25.4)830 (24.3)687 (27.0)650 (26.9)
Survival time (months)<0.0001
 Median33.0398.0307.044.0
 Mean (Sd)160.6 (7.8)308.0 (2.6)279.9 (3.7)224.9 (4.7)167.3 (4.5)
Mortality status1043.3 (4)<0.0001
 Alive375 (48.6)4831 (79.7)2538 (74.2)1586 (62.3)1174 (48.6)
 Dead396 (51.4)1230 (20.3)883 (25.8)958 (37.7)1244 (51.4)

Notes and Abbreviations. The significance level is 0.01, CI: confidence interval, df: degrees of freedom. The median survival time for age group 1–4 years was not estimated as 50% of patients did not die in this group at any point of time (that is the KM estimator for 1–4 age group never reaches a probability of dying greater than 0.5).
(c) Five-year interval survival percentage of pediatric leukemia patients overall and by age group at diagnosis

Survival time interval (months)Overall survival (%) Survival percentage by age group (years) at diagnosis
<11–45–910–1415–19

0–6067.943.379.875.360.444.8
60–12063.040.175.569.154.939.8
120–18061.039.573.566.852.438.1
180–24059.637.672.264.951.037.6
240–30058.936.771.563.949.737.6
300–36057.136.770.362.848.035.8
360–42055.636.769.160.544.832.4