Large Prostate Volume Does Not Negatively Impact Health-Related Quality of Life in Patients with Prostate Cancer Treated with Ultrahypofractionated Stereotactic Body Radiotherapy

Background: Survival outcomes after primary radiotherapy for localized prostate cancer (PCa) are excellent, regardless of the specific treatment modality. For this reason, health-related quality of life (HRQOL) has come to play an ever more important role in treatment selection. Stereotactic body radiation therapy (SBRT) is increasingly used to treat patients with PCa. However, the impact of prostate volume on HRQOL is not clear. In this study, we aimed to determine whether a large prostate volume negatively influences HRQOL outcomes in patients undergoing ultrahypofractionated SBRT. Material and Methods: We conducted a prospective study of 530 men with low- and intermediate-risk localized PCa. All patients were treated from 2013 to 2017 with SBRT (Cyberknife system). HRQOL data were collected at baseline (pre-treatment), immediately after treatment, and at 12 and 24 months. QOL variables were assessed with the European Organization for Research and Treatment of Cancer QLQ-C30 and PR-25 module. Differences in the QLQ-C30 scales were considered clinically relevant when the change was >10 points. For the analysis, patients were classified into two groups according to prostate volume (≤60 vs. >60 cm(3)). Results: The prostate volume was ≤60 cm(3) in 415 patients (78.3%) and >60 cm(3) in 115 (21.7%). No between-group differences were observed at baseline for any of the following variables: clinical stage; hormonal therapy; marital status; educational level; or employment status. No clinically-significant deterioration (functional and symptom scales) was observed in either group between the baseline and 24-month assessment. There were no clinically-relevant differences between the groups on any of the HRQOL variables, regardless of the prostate volume. Conclusions: This study shows that a large prostate volume (>60 cm(3)) does not appear to negatively impact HRQOL outcomes at two years in patients with localized prostate cancer treated with ultrahypofractionated SBRT administered with the CyberKnife system.