Summary of randomised controlled trials examining the effect of PCI on NCF and SRS versus WBRT+SRS
| Reference | Patients | Primary end point | Dose | Baseline | Main results | Statistical significance |
|---|---|---|---|---|---|---|
| PCI: Arriagada et al76 | n=294, SCLC | Survival | 24 Gy | Baseline for ‘higher functions’ unpublished. Entire neuropsychological examination: #free from any abnormalities Control: 44 PCI: 50 | % With cognitive impairment assessed by ‘cumulative incidence of changes in neuropsychological assessment’ (higher functions)* Control: 36% PCI: 30% | N |
| PCI: Gregor et al63 | n=314, SCLC | Survival | 8–36 Gy | PASAT Control: 24% PCI: 24% CFT Control: 41% PCI: 42% AVLT learning Control: 31% PCI: 38% AVLT retention Control: 27% PCI: 24% | % With cognitive impairment assessed by PASAT (1 year) Control: 17% PCI: 31% CFT (1 year) Control: 17% PCI: 15% AVLT learning (1 year) Control: 40% PCI: 69% AVLT retention (1 year) Control: 38% PCI: 0% | N |
| PCI: Wolfson et al74 | n=264, SCLC | NCF | 25 versus 36 Gy | Statistically significant differences for the COWAT (p=0.03) and TMT-A (adjusted p=0.03) at baseline among the three treatment groups | % With cognitive impairment as defined by significant decrease in at least one NCF measure (HVLT, COWAT, TMT-A or TMT-B) 25 Gy: 62%; 36 Gy: 85% | Y |
| PCI: Le Pechoux et al77 | n=720, SCLC | Survival | 25 versus 36 Gy | % Of patients with abnormal QoL-cognitive functioning (scale <75) 25 Gy: 23%; 36 Gy: 25% | % With cognitive impairment at 36 months as assessed by a physician using a scale of 1–4 at 2 years† 25 Gy: 35%; 36 Gy: 47% | N |
| PCI: Sun et al75 | n=340, NSCLC | Survival | 30 Gy | Unavailable. Baseline used for measurement of decline | % With cognitive impairment at 1 year as assessed by HVLT Control: 12% PCI: 41% | Y |
| SRS versus WBRT+SRS: Aoyama et al26 78 | n=132, misc. metastases | Survival | 30 Gy WBRT | Insignificant SRS: 27 WBRT+SRS: 27 p=0.86 | Median MMSE score at 12 months SRS: 28 SRS+WBRT: 27 % With cognitive impairment assessed at 12 months as assessed by MMSE* SRS: 32.5% SRS+WBRT: 48.1% % With cognitive impairment assessed at 36 months as assessed by MMSE1 SRS: 48.1% SRS+WBRT: 85.3% | N |
| SRS versus WBRT+SRS: Chang et al27 | n=58, misc. metastases | NCF | 30 Gy WBRT | HVLT (total recall) SRS: –0.80 (1.53) SRS+WBRT: –1.12 (1.50) HVLT (delayed recall) SRS: –0.73 (1.31) SRS+WBRT: –1.32 (1.74) | % With cognitive impairment assessed at 3 months by HVLT (total recall) SRS: 24% SRS+WBRT: 52% HVLT (delayed recall) SRS: 6% SRS+WBRT: 22% | Y |
*Assessment described as temporo-spatial orientation, memory, judgment (critique of an absurd story), language (spontaneous, dictated sentence and object names), praxis (drawing, dressing and ideomoter praxis) and mood status. Details of how these assessments were made were absent in the manuscript.
†Patients could either be rated as normal or have a grade 1 (minor loss of memory, reason and/or judgment), grade 2 (moderate loss of memory, reason and/or judgment), grade 3 (major intellectual impairment) or grade 4 (complete memory loss/incapable of rational thought) cognitive impairment.
AVLT, Auditory Verbal Learning Test; CFT, Complex Figure Test; COWAT, Controlled Oral Word Association; HVLT, Hopkins Verbal Learning Test; MMSE, Mini-Mental State Exam; NCF, neurocognitive function; NSCLC, non-small cell lung cancer; PASAT, Paced Auditory Serial Addition Test; PCI, prophylactic cranial irradiation; QoL, quality of life; SCLC, small cell lung cancer; SRS, stereotactic radiosurgery; TMT, Trail-Making Test; WBRT, whole brain radiation therapy.