Stereotactic ablative radiotherapy (SABR) is a form of external beam radiotherapy that accurately delivers a high dose of irradiation in one or few fractions to extracranial tumors. Studies have shown SABR to be safe and effective for treating oligometastatic prostate cancer lesions, with low toxicity and good local tumor control. However, larger trials like STOMP and ORIOLE that compared SABR to surveillance found no reduction in metastatic progression, possibly due to limitations in accounting for disease aggressiveness between treatment groups. SABR remains a promising option for select oligometastatic prostate cancer patients.

1. Oligometastatic Prostate Cancer-targeting
with radiation

2. Contents
 Oligometastatic Cancer –definition
 Rationale for metastatic directed therapy
 SABR –studies
 Trials

3. Definition
 No thoughtful/formal staging-UICC 8th edition doesn’t have a
an assigned prognostic group
 <=3 lesions outside pelvis
 <=5 lesions limited to lymph nodes/bones
 <=10 lesions with no visceral involvement
 Select studies defining the same
 Imaging also need to be standardized Tc99>>>PSMA PET-CT
 Synchronous vs Metachronous ?

7. Stereotactic Ablative Radiotherapy (SABR)
 5 studies –retrospective small number
 Most of the targets bones >>some visceral, nodes
 Only take away message is that it’s safe
 No G-III toxicity
 Even G-II quite low
 Local control pretty good –ablative
 Freedom from androgen deprivation 2 studies managed for 2-3 years

8. 2 Trials
 STOMP (Surveillance or metastasis-directed Therapy for
OligoMetastatic Prostate cancer recurrence)
 ORIOLE trial (Observation Versus Stereotactic Ablative
RadiatIOn for OLigometastatic Prostate CancEr)

11. Note
 The STOMP trial showed a trend towards delayed ADT, but
failed to show a reduction in metastatic progression.
An important limitation of both the STOMP
and ORIOLE studies is that the investigators
were unable to account for length-bias and may
well have included metastatic patients with
slower growing disease.

14. (1) a method of external
beam radiotherapy
(EBRT) that
(2) accurately delivers a
(3) high dose of
irradiation in
(4) one or few treatment
fractions to an
(5) extracranial target.
 AAPM Task
Group 101
 ASTRO and ACR
SBRT DEFINITION

16. SBRT spine-mets
 67 yr old male case of Ca Prostate post-op with spine recurrence
(cord compression)-D5-D6 level
 Post tumor decompression/spine stabilization patient planned for
SBRT to D5-D6 level
 RT dose 30 Gy/ 5fx @iso (80 % peripheral dose)