Ten-Year Results From a Phase II Study on Image Guided, Intensity Modulated Radiation Therapy With Simultaneous Integrated Boost in High-Risk Prostate Cancer

Christian Ekanger; Svein Inge Helle; Daniel Heinrich; Dag Clement Johannessen; Ása Karlsdóttir; Yngve Nygård; Ole Johan Halvorsen; Lars Reisæter; Rune Kvåle; Liv Bolstad Hysing; Olav Dahl

doi:10.1016/j.adro.2019.11.007

Ten-Year Results From a Phase II Study on Image Guided, Intensity Modulated Radiation Therapy With Simultaneous Integrated Boost in High-Risk Prostate Cancer

Adv Radiat Oncol. 2019 Dec 9;5(3):396-403. doi: 10.1016/j.adro.2019.11.007. eCollection 2020 May-Jun.

Authors

Christian Ekanger¹, Svein Inge Helle¹, Daniel Heinrich¹, Dag Clement Johannessen¹, Ása Karlsdóttir¹, Yngve Nygård², Ole Johan Halvorsen^{3

4}, Lars Reisæter^{5

6}, Rune Kvåle¹, Liv Bolstad Hysing^{7

8}, Olav Dahl^{1

9}

Affiliations

¹ Department of Oncology and Institute of Clinical Science, Haukeland University Hospital, Bergen, Norway.
² Department of Urology, Haukeland University Hospital, Bergen, Norway.
³ Centre for Cancer Biomarkers CCBIO, Department of Clinical Medicine, University of Bergen, Norway.
⁴ Department of Patohology, Haukeland University Hospital, Bergen, Norway.
⁵ Department of Radiology, Haukeland University Hospital, Bergen, Norway.
⁶ Department of Clinical Medicine, University of Bergen, Bergen, Norway.
⁷ Institute of Physics and Technology, University of Bergen, Bergen, Norway.
⁸ Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway.
⁹ Department of Clinical Science Faculty of Medicine, University of Bergen, Norway.

Abstract

Purpose: There is no consensus on how to treat high-risk prostate cancer, and long-term results from hypofractionated radiation therapy are lacking. We report 10-year results after image guided, intensity modulated radiation therapy with hypofractionated simultaneous integrated boost and elective pelvic field.

Methods and materials: Between 2007 and 2009, 97 consecutive patients with high-risk prostate cancer were included, treated with 2.7 to 2.0 Gy × 25 Gy to the prostate, seminal vesicles, and elective pelvic field. Toxicity was scored according to Radiation Therapy Oncology Group criteria and biochemical disease-free survival (BFS) defined by the Phoenix definition. Patients were subsequently divided into 3 groups: high risk (HR; n = 32), very high risk (VHR; n = 50), and N+/s-prostate-specific antigen (PSA) ≥100 (n = 15). Differences in outcomes were examined using Kaplan-Meier analyses.

Results: BFS in the patients at HR and VHR was 64%, metastasis-free survival 80%, prostate cancer-specific survival 90%, and overall survival (OS) 72%. VHR versus HR subgroups demonstrated significantly different BFS, 54% versus 79% (P = .01). Metastasis-free survival and prostate cancer-specific survival in the VHR group versus HR group were 76% versus 87% (P = .108) and 74% versus 100% (P = .157). Patients reaching nadir PSA <0.1 (n = 80) had significantly better outcomes than the rest (n = 17), with BFS 70% versus 7% (P < .001). Acute grade 2 gastrointestinal tract (GI) and genitourinary tract (GU) toxicity occurred in 27% and 40%, grade 3 GI and GU toxicity in 1% and 3%. Late GI and GU grade 2 toxicity occurred in 1% and 8%.

Conclusions: High-risk prostate cancer patients obtained favorable 10-year outcomes with low toxicity. There were significantly better results in the HR versus the VHR group, both better than the N+/PSA ≥100 group. A nadir PSA value < 0.1 predicted good prognosis.