Table 1: (a) Study variables characterized by sex of pediatric patients diagnosed with leukemia, 1973–2006. (b) Five-year interval survival percentage of pediatric leukemia patients overall and by sex.
(a)

CovariatesBoysGirls 𝜒 2 (df) 𝑃 value
n (%)n (%)

Race3.81 (3)0.28
 White7087 (88.2)5348 (81.1)
 Black657 (7.6)555 (8.4)
 Others843 (9.8)663 (10.1)
 Unknown35 (0.4)27 (0.4)
Age at diagnosis (yrs)49.76 (4)<0.0001
 <1.0386 (4.5)385 (5.8)
 1.0−4.03411 (39.6)2650 (40.2)
 5.0–9.01871 (21.7)1550 (23.5)
 10.0–14.01450 (16.8)1094 (16.5)
 15.0−19.01504 (17.4)914 (13.9)
Year of diagnosis5.72 (6)0.46
 1973–1977683 (7.9)488 (7.4)
 1978–1982641 (7.4)516 (7.8)
 1983–1987711 (8.2)550 (8.3)
 1988–1992865 (10.0)661 (10.0)
 1993–19981290 (15.0)1005 (15.2)
 1999–20022167 (25.1)1720 (26.1)
 2003–20062265 (26.3)1653 (25.1)
Number of primaries3.16 (1)0.07
 1.08499 (98.6)6475 (98.2)
 ≥ 2.0123 (1.4)118 (1.8)
Survival time (months)<0.0001
 Median45.051.0
 Mean (sd)79.32 (88.4)85.87 (93.06)
Mortality status23.6 (1)<0.0001
 Alive5815 (67.4)4689 (71.1)
 Dead2807 (32.6)1904 (28.9)
Radiation23.2 (1)<0.0001
 Yes1622 (18.8)1043 (15.8)
 No7000 (81.2)5550 (84.2)

Abbreviations and notes: sd = standard deviation. The significance level is 0.01 (1% type 1 error tolerance).
(b)

Survival percentage by sex
Survival time interval (months)Overall survival (%)Boys (%)Girls (%)

0–6067.966.370.1
60–12063.060.965.7
120–18061.058.863.8
180–24059.657.362.6
240–30058.956.661.8
300–36057.155.760.1
360–42055.653.958.0

Notes: the maximum followup time was 408 months. The survival interval for the last row is 360–408 months but presented as 360–420 to meet the five-year survival cutoff point.