Factors involved in maintaining prolonged functional independence following supratentorial glioblastoma resection. Clinical article

Abstract

Object: The median survival duration for patients with glioblastoma is approximately 12 months. Maximizing quality of life (QOL) for patients with glioblastoma is a priority. An important, yet understudied, QOL component is functional independence. The aims of this study were to evaluate functional outcomes over time for patients with glioblastoma, as well as identify factors associated with prolonged functional independence.

Methods: All patients who underwent first-time resection of either a primary (de novo) or secondary (prior lower grade glioma) glioblastoma at a single institution from 1996 to 2006 were retrospectively reviewed. Patients with a Karnofsky Performance Scale (KPS) score ≥ 80 were included. Kaplan-Meier, log-rank, and multivariate proportional hazards regression analyses were used to identify associations (p < 0.05) with functional independence (KPS score ≥ 60) following glioblastoma resection.

Results: The median follow-up duration time was 10 months (interquartile range [IQR] 5.6-17.0 months). A patient's preoperative (p = 0.02) and immediate postoperative (within 2 months) functional status was associated with prolonged survival (p < 0.0001). Of the 544 patients in this series, 302 (56%) lost their functional independence at a median of 10 months (IQR 6-16 months). Factors independently associated with prolonged functional independence were: preoperative KPS score ≥ 90 (p = 0.004), preoperative seizures (p = 0.002), primary glioblastoma (p < 0.0001), gross-total resection (p < 0.0001), and temozolomide chemotherapy (p < 0.0001). Factors independently associated with decreased functional independence were: older age (p < 0.0001), coexistent coronary artery disease (p = 0.009), and incurring a new postoperative motor deficit (p = 0.009). Furthermore, a decline in functional status was independently associated with tumor recurrence (p = 0.01).

Conclusions: The identification and consideration of these factors associated with prolonged functional outcome (preoperative KPS score ≥ 90, seizures, primary glioblastoma, gross-total resection, temozolomide) and decreased functional outcome (older age, coronary artery disease, new postoperative motor deficit) may help guide treatment strategies aimed at improving QOL for patients with glioblastoma.

Fig 1

Kaplan-Meier plot of maintaining functional independence for all patients with glioblastoma in this study. The median time for maintaining functional independence was 10 months, whereas the 6-, 12-, and 18-month functional independence rates were 68%, 41%, and 27%, respectively.

Fig. 2

Graph of maintaining functional independence for patients with glioblastoma comparing those patients with a preoperative KPS score > 80 versus 80. The median time for maintaining functional independence for patients with a preoperative KPS score > 80 was 11 months, whereas the 6-, 12-, and 18-month functional independence rates were 74%, 45%, and 30%, respectively. The median time for maintaining functional independence for patients with a preoperative KPS score of 80 was 9 months, whereas the 6-, 12-, and 18-month functional independence rates were 62%, 38%, and 23%, respectively. These groups were significantly different (p = 0.006).

Fig. 3

Graph of maintaining functional independence in patients with a primary (de novo) versus secondary (from lower grade glioma [LGG]) glioblastoma resection. The median duration for maintaining functional independence for patients with primary glioblastoma was 12 months, whereas the 6-, 12-, and 18-month functional independence rates were 74%, 48%, and 35%, respectively. The median time for maintaining functional independence for patients with secondary glioblastoma was 8 months, whereas the 6-, 12-, and 18-month functional independence rates were 58%, 31%, and 12%, respectively. These groups were statistically different (p < 0.0001).