External beam irradiation of craniopharyngiomas: long-term analysis of tumor control and morbidity.

Abstract

To delineate the long-term control and morbidity with external beam radiotherapy (EBRT) of craniopharyngiomas. Between 1971 and 1992, 24 craniopharyngioma patients underwent EBRT at the University of Pittsburgh. Most (19 of 24) were treated within 1-3 months after subtotal resection. The other prior surgical procedures were biopsy (n = 2) and gross total resection (n = 1); 2 patients did not undergo any surgical procedure. The median follow-up was 12.1 years. The median patient age was 29 years (range 5-69). The total radiation doses varied from 36 to 70 Gy (median 59.75). The normalized total dose (NTD, biologically equivalent dose given in 2 Gy/fraction [alpha/beta ratio = 2]) varied from 28 to 83 Gy (median 55.35). The actuarial survival rate at 10 and 20 years was 100% and 92.3%, respectively. The actuarial local control rate at 10 and 20 years was 89.1% and 54.0%, respectively. No local failures occurred with doses >or=60 Gy (n = 12) or NTDs >or=55 Gy. The complication-free survival rate at 10 and 20 years was 80.1% and 72.1%, respectively. No complications were noted with an NTD of <or=55 Gy. The actuarial survival free from any adverse outcome (recurrence or complication) was 70.1% and 31.8% at 10 and 20 years, respectively. The adverse outcome-free survival appeared optimized (at 73%) with an NTD of 55-63 Gy. Multivariate analysis found that tumor control correlated significantly with the total dose (p = 0.02), treatment complications with NTD (p = 0.008), and adverse outcome with hypopituitarism on presentation (p = 0.03). We recommend treating craniopharyngioma with 1.6-1.7-Gy dose fractions to 60 Gy to optimize outcome from EBRT.