paediatrics Brussels 17

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Volume 92 Number 5 2015

Cognitive performance in the PNET4 study

However, nonparticipants tended to be older at diagnosis (mean Z 11.89 vs 9.31, P < .01), suggesting that older participants had a lower probability of receiving a cognitive assessment.

(65.83 versus 81), and extra ocular movements deficits were associated with lower mean VIQ (90.37 versus 98.27, P < .05 in all cases). The presence of any perioperative complications, including cerebellar mutism, was also associated with lower mean scores of PSI (68.75 versus 81.14, P Z .04). No other differences were observed for the remaining postoperative characteristics. Due to these as- sociations, the effects of perioperative complications (or alternatively, cerebellar mutism) were controlled for in the regression analyses described below. Country by treatment interactions were not significant. In univariate analyses, all cognitive outcomes were similar between HFRT and STRT arms ( Table 2 ). However, PSI tended to be higher in the HFRT arm (difference of 7.9 [95% confidence interval [CI]: 0.14 to 15.9], P Z .05). In younger participants ( < 8 years of age at diagnosis), VIQ tended to be higher in the HFRT arm (difference of 12.02 [95% CI: 2.4-21.7], P Z .02). For the remaining measure- ments, no other differences were observed between arms when age at diagnosis was considered. The results of regression analyses paralleled those of univariate analyses described above. In the full sample, allocation to HFRT showed a marginally significant trend to higher PSI scores ( F Z 4.74, P Z .03), and in participants whose age at diagnosis was < 8 years, it showed a marginally significant association with higher VIQ scores ( F Z 7.1, P Z .01). No other significant effect or strong trend associated with treatment allocation was found on the remaining cognitive outcomes, either for the total sample or for the subgroup of participants whose age at diagnosis was > 8 years. These same analyses were redone after exclusion Effects of treatment on cognitive outcomes

Demographic and baseline characteristics for participants

Participants who received HFRT and STRT were similar regarding sex, age at diagnosis, age at assessment, and in- terval between diagnosis and assessment ( Table 1 ). Regarding pre- and postoperative characteristics, the 2 groups were also similar except that a slightly higher rate of postoperative complications and extraocular movement deficits were observed in participants receiving HFRT compared to those receiving STRT.

Cognitive outcomes at posttreatment evaluation for the whole group of participants

Distribution of the 5 cognitive outcomes indicated consid- erable variability, with scores ranging from 40 to 145. Using a cutoff point of 2 SD, 12.4% of the FSIQ, 8% of VIQ, 12.5% of PIQ, 7% of WMI, and 33.7% of PSI scores were in the lower extreme range. Cognitive outcomes were similar according to sex, country, age at diagnosis, age at assessment, and interval between diagnosis and assessment. Mean scores tended to be lower ( P < .05 in all cases) in the presence of post- operative ataxia: FSIQ (85.01 versus 94.52), VIQ (89.76 versus 99.4), WMI (89.34 versus 95.29) and PSI (73.82 versus 85.54). Postoperative cerebellar mutism was asso- ciated with lower mean PIQ (79.33 versus 89.09) and PSI

Descriptive statistics of the study’s participants according to treatment allocation HFRT

Table 1

STRT

N M SD Range

N M SD Range

Demographic characteristic (ref) Age at diagnosis (y) * Age at diagnosis ( < 8 y) (%) y

71 9.1

3.23

4-17.6

66 9.5

3.14

4.3-17.3

31 (43.7) 71 14.3

-

-

25 (37.9)

-

-

Age at assessment *

4.48 2.81

6.2-24.9 66 14.9 0.08-9.9 66 5.4

4.11

6.1-24.7

Interval from diagnosis (y) *

71 5.2

2.53 0.58-10.5

No. of males (%) y

46 (64.8)

- -

- -

41 (62.1)

- -

- -

No. of premorbid developmental impairments (%) y

2 (2.8)

4 (6.1)

Postoperative status No. of postoperative complications (%) y No. with impaired consciousness (%) y

10 (14.1)

- - - - -

- - - - -

3 (4.6) 2 (3.1)

- - - - -

- - - -

0 (0)

No. with impaired nerve III (%) y

35 (53) 34 (58.6)

23 (37.7) 36 (64.3)

No. with ataxia (%) y

No. with cerebellar mutism (%) y - Abbreviations: HFRT Z hyperfractionated radiation therapy; M Z mean; SD Z standard deviation; STRT Z standard radiation therapy. * Student t test. y Khi-2 de Mantel-Haenszel. 6 (8.5) 3 (4.6)