High-dose-rate brachytherapy boost for elderly patients with intermediate to high-risk prostate cancer: 5-year clinical outcome of the PROSTAGE cohort

Delphine Marotte; Jocelyn Gal; Renaud Schiappa; Mathieu Gautier; Rabia Boulahssass; Marie-Eve Chand-Fouche; Jean-Michel Hannoun-Levi

doi:10.1016/j.ctro.2022.05.001

High-dose-rate brachytherapy boost for elderly patients with intermediate to high-risk prostate cancer: 5-year clinical outcome of the PROSTAGE cohort

Clin Transl Radiat Oncol. 2022 May 21:35:104-109. doi: 10.1016/j.ctro.2022.05.001. eCollection 2022 Jul.

Authors

Delphine Marotte¹, Jocelyn Gal², Renaud Schiappa², Mathieu Gautier¹, Rabia Boulahssass³, Marie-Eve Chand-Fouche¹, Jean-Michel Hannoun-Levi¹

Affiliations

¹ Department of Radiation Oncology, Antoine Lacassagne Cancer Center, University of Côte d'Azur, 33 avenue Valombrose, 06189 Nice Cedex 2, Nice, France.
² Department of Statistics, Antoine Lacassagne Cancer Center, University of Côte d'Azur, Nice, France.
³ Geriatric Coordination Unit for Geriatric Oncology (UCOG) PACA Est, CHU de NICE, University of Cote d'Azur, Oncoage, Nice, France.

Abstract

Purpose: To analyze the oncological outcome in elderly (>70 years) prostate cancer after high-dose rate brachytherapy (HDB) boost.

Materials/methods: In this retrospective study, patients with intermediate (IR) and high-risk (HR) prostate cancer underwent external beam radiation therapy (EBRT) followed by HDB boost with/without androgen deprivation therapy (ADT). The impact of age (≤70y vs. > 70y) was investigated. Oncological outcome focused on biochemical relapse-free survival (bRFS), cause-specific (CSS) and overall survival (OS). Late genito-urinary (GU) and gastro-intestinal (GI) toxicities were investigated.

Results: From 07/08 to 01/22, 518 pts received a HDB boost, and 380 were analyzed (≤70y:177pts [46.6%] vs. > 70y:203pts [53.4%]). Regarding NCCN classification, 98 pts (≤70y: 53pts; >70y: 45pts; p = 0.107) and 282 pts (≤70y: 124pts; >70y: 158pts; p = NS) were IR and HR pts respectively. Median EBRT dose was 46 Gy [37.5-46] in 23 fractions [14-25]. HDB boost delivered a single fraction of 14/15 Gy (79%). ADT was used in 302 pts (≤70y: 130pts; >70y: 172pts; p = 0.01). With MFU of 72.6 months [67-83] for the whole cohort, 5-y bRFS, 5-y CSS and 5-y OS were 88% [85-92], 99% [97-100] and 94% [92-97] respectively; there was no statistical difference between the two age groups except for 5-y CSS (p = 0.05). Late GU and GI toxicity rates were 32.4% (G ≥ 3 7.3%) and 10.1% (no G3) respectively.

Conclusions: For IR and HR prostate cancers, HDB boost leads to high rates of disease control with few late G ≥ 3 GU/GI toxicities. For elderly pts, HDB boost remains warranted mainly in HR pts, while competing comorbidity factors influence OS.

Keywords: 3DRT, three-dimensional radiation therapy; ADT, androgen deprivation therapy; BT, brachytherapy; Boost; Brachytherapy; CSS, cancer specific survival; CT, computerized tomography; CTCAE, common terminology criteria for adverse events; CTV, clinical target volume; Comorbidity; D100, dose delivered to 100% of CTV; D2cc, dose delivered to 2cc of the organ at risk; D90, dose delivered to 90% of the clinical target volume; DFS, disease-free survival; DNR, dose non-homogeneity ratio; EBRT, external beam radiation therapy; EQD2, equivalent dose at 2 Gy per fraction; Eldery; GI, gastro-intestinal; GU, genito-urinary; HDB, high-dose rate brachytherapy; HR, high risk; High-risk; IMRT, intensity modulated radiation therapy; IR, intermediate risk; ISUP, International Society of Urological Pathology; LDR, low dose-rate; LR, low risk; MFU, median follow up; MRI, magnetic resonance imaging; NCCN, national comprehensive cancer network; OAR, organs at risks; OS, overall survival; Oncogeriatric assessment; PC, prostate cancer; PET, positron emission tomography; PSA, prostate specific antigen; Prostate cancer; QoL, quality of life; RCT, randomized clinical trial; TD, total dose; V100, percentage of the clinical target volume receiving 100% of the prescribed dose; V150, percentage of the clinical target volume receiving 150% of the prescribed dose; V200, percentage of the clinical target volume receiving 200% of the prescribed dose; Vr100, percentage of the rectum volume receiving 100% of the prescribed dose; Vr90, percentage of the rectum volume receiving 90% of the prescribed dose; Vu115, percentage of the urethra volume receiving 115% of the prescribed dose; Vu125, percentage of the urethra volume receiving 125% of the prescribed dose; bRFS, biochemical relapse free survival; lRFS, local relapse free survival; mRFS, metastatic relapse-free survival; pts, patients; rRFS, regional lymph-node relapse free survival.