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Fractionated stereotactic body radiotherapy for up to five prostate cancer oligometastases: Interim outcomes of a prospective clinical trial
Author(s) -
Bowden Patrick,
See Andrew W.,
Frydenberg Mark,
Haxhimolla Hodo,
Costello Anthony J.,
Moon Daniel,
Ruljancich Paul,
Grummet Jeremy,
Crosthwaite Alan,
Pranavan Ganes,
Peters Justin S.,
So Kevin,
Gwini Stella M.,
McKenzie Dean P.,
Nolan Skye,
Smyth Lloyd M.L.,
Everitt Craig
Publication year - 2019
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.32509
Subject(s) - medicine , prostate cancer , interim analysis , prospective cohort study , androgen deprivation therapy , radiation therapy , radiosurgery , interim , prostate , surgery , clinical trial , urology , oncology , cancer , history , archaeology
Stereotactic body radiotherapy (SBRT) can delay escalation to systemic treatment in men with oligometastatic prostate cancer (PCa). However, large, prospective studies are still required to evaluate the efficacy of this approach in different patient groups. This is the interim analysis of a prospective, single institution study of men relapsing with up to five synchronous lesions following definitive local treatment for primary PCa. Our aim was to determine the proportion of patients not requiring treatment escalation following SBRT. In total, 199 patients were enrolled to receive fractionated SBRT (50 Gray in 10 fractions) to each visible lesion. Fourteen patients were castration resistant at enrolment. The proportion of patients not requiring treatment escalation 2 years following SBRT was 51.7% (95% CI: 44.1–59.3%). The median length of treatment escalation‐free survival over the entire follow‐up period was 27.1 months (95% CI; 21.8–29.4 months). Prior androgen deprivation therapy (ADT) predicted a significantly lower rate of freedom from treatment escalation at 2 years compared to no prior ADT (odds ratio = 0.21, 95% CI: 0.08–0.54, p = 0.001). There was no difference in the efficacy of SBRT when treating 4–5 vs . 1–3 initial lesions. A prostate‐specific antigen (PSA) decline was induced in 75% of patients, with PSA readings falling to an undetectable level in six patients. No late grade three toxicities were observed. These interim results suggest that SBRT can be used to treat up to five synchronous PCa oligometastases to delay treatment escalation.