Effects of radiation and chemotherapy on cognitive function in patients with high-grade glioma

The effect of radiotherapy on the long-term cognitive performance of patients treated for intracranial neoplasm is a major concern to clinicians and patients, particularly as long-term survival or cure is possible for a small minority of patients. To assess the effects of cranial radiotherapy and chemotherapy on the cognitive performance of high-grade glioma patients, we analyzed cognitive performance data collected in a series of prospective clinical trials.

We studied 701 high-grade brain tumor patients entered onto two consecutive North Central Cancer Treatment Group (NCCTG) randomized treatment trials designed to compare radiotherapy and carmustine (BCNU) versus radiotherapy and 1-(2-chloroethyl)-3(2,6 dioxo-l-piperidyl)-1-nitrosource a (PCNU) (first trial) and radiotherapy and BCNU and interferon alfa (IFN) versus radiotherapy and BCNU (second trial). Folstein Mini-Mental Status Exam (MMSE) score and Eastern Cooperative Oncology Group (ECOG) performance score (PS) recorded at baseline and 6, 12, 18, and 24 months were analyzed to assess cognitive and physical function over time. Patients who did not demonstrate tumor progression within 60 days of the assessment time were considered nonprogressors at that evaluation. A loss of greater than 3 points on the MMSE was considered significant deterioration.

The number of patients who experienced a greater than 3-point decrease in MMSE from baseline was 13 of 119 nonprogressors (10.9%; 95% confidence interval [CI], 6.3% to 18.9%) at 6 months, three of 54 nonprogressors (5.5%; 95% CI, 0.5% to 12.8%) at 12 months, three of 30 nonprogressors (10%; 95% CI, 2.1% to 26.5%) at 18 months, and four of 22 nonprogressors (18.2%; 95% CI, 5.2% to 40.3%) at 24 months. The CIs at all times overlapped, which indicates no statistically significant increase in the percentage of patients who experienced a significant decrease in their MMSE score. Patients who demonstrated a significant decrease in their MMSE score were significantly older than those who did not (P = .0017) at 6 months and remained so throughout follow-up; moreover, they had a significantly shorter time to progression and death. ECOG PS was strongly negatively correlated with MMSE score throughout the study, and MMSE score at all time intervals was correlated with baseline PS.

In this population of glioma patients who received radiotherapy, there is no clear trend to cognitive worsening. Factors such as older age, poorer PS, and subclinical tumor progression may be more significant factors in those patients who did demonstrate a significant cognitive decline.