Dose escalation and quality of life in patients with localized prostate cancer treated with radiotherapy: long-term results of the Dutch randomized dose-escalation trial (CKTO 96-10 trial)

Purpose: To assess the impact of dose escalation of radiotherapy on quality of life (QoL) in prostate cancer patients.

Patients and methods: Three hundred prostate cancer patients participating in the Dutch randomized trial (CKTO 69-10) comparing 68 Gy with 78 Gy were the subject of this analysis. These patients filled out the SF-36 QoL questionnaire before radiotherapy (baseline) and 6, 12, 24, and 36 months thereafter. Changes in QoL over time of ≥10 points were considered clinically relevant. Repeated-measures regression analyses were applied to estimate and test the QoL changes over time, the differences between the two arms, and for association with a number of covariates.

Results: At 3-year follow-up, the summary score physical health was 73.2 for the 68-Gy arm vs. 71.6 for the 78-Gy arm (p = 0.81), and the summary score mental health was 76.7 for the 68-Gy arm vs. 76.1 for the 78-Gy arm (p = 0.97). Statistically significant (p < 0.01) deterioration in QoL scores over time was registered in both arms in six scales. The deterioration over time was more pronounced in the high-dose arm for most scales. However, clinically relevant deterioration (>10 points) was seen for only two scales. None of the tested covariates were significantly correlated with QoL scores.

Conclusion: Dose escalation did not result in significant deterioration of QoL in prostate cancer patients. In both randomization arms, statistically significant decreases in QoL scores over time were seen in six scales. The deterioration of QoL was more pronounced in the physical than in the mental health domain and in some scales more in the high- than in the low-dose arm, but the differences between arms were not statistically significant.