Silvia Johansson1*, Mia Emanuelsson1, Petra Witt Nyström1, Ingrida Verbiené1, Ulf Isacsson2# and Ingela Turesson1#
1Department of Immunology, Genetics and Pathology, Divison of Oncology, Uppsala University Hospital, Uppsala, Sweden 2Department of Medical Physics, Uppsala University Hospital, Uppsala, Sweden #Authors have contributed equallyFulltext PDF
Purpose: Evaluation of hypofractionated photon boost combined with 2-Gy fractions to 50 Gy locally or including the pelvic lymph nodes, in prostate cancer with high-risk features. Patients and Methods: 20 Gy in 4 daily fractions was delivered to prostate using a rectal retraction rod, increasing the distance to rectum, on average 3 mm. Another 50 Gy was given locally or including the pelvic nodes. Advanced imaging was used for primary staging and localization of biochemical relapse. Endpoints were biochemical, local and regional relapse-free, distant metastasisfree survival, and progression-free, prostate cancer-specific and overall survival. Results: 255 patients with N0M0 disease were treated: 160 (63%) stage T3/T4 and 119 (47%) ISUP group 4-5. The majority, 184 (96%) patients, in the high- and very high-risk groups received longterm Androgen Deprivation Therapy (ADT). Of the 93 high- and 98 very high-risk patients, 47 (51%) and 72 (73%) received pelvic node irradiation, included at the doctor’s discretion. Median follow-up was 51 months (IQR 24 to 84). The 5-year PSA relapse-free survival was 90%, 88%, and 71% for intermediate, high, and very high-risk patients, respectively. Pelvic lymph node irradiation improved and ISUP group 4 to 5 impaired all tumor efficacy measures. Worsening of symptoms from the urinary and gastrointestinal tract evaluated in 135 patients was mild to acceptable. Conclusion: Use of a rectal retractor rod for a hypofractionated photon boost was effective and appropriate for selected patients. Elective pelvic node irradiation improved all tumor efficacy measures in very high-risk patients being on long-term ADT, probably explained by the low sensitivity to ADT experienced by the far majority of this cohort having Gleason score 9 to 10. Radiation-induced genitourinary and gastrointestinal side effects were moderate.
Prostate cancer; Hypofractionated radiotherapy; Rectal retraction rod; Photon boost; Clinical outcome
Johansson S, Emanuelsson M, Nyström PW, Verbiené I, Isacsson U, Turesson I. Hypofractionated Photon Boost with 4 Fractions of 5 Gy Using a Rectal Retraction Rod Prior to 50 Gy Locally or Including Pelvic Lymph Nodes in High- and Very High-Risk Prostate Cancer. Ann Radiat Ther Oncol. 2022; 3(1): 1021..