Table 1.

Prospective trials evaluating the role of radiotherapy in (oligo)metastatic prostate cancer.

Study	Disease Type	Metastatic Burden	Study Type	N	Randomization (if applicable)	Primary Outcome	Result	Toxicity
STAMPEDE Arm H	De novo metastatic disease	Any metastatic burden	Phase III RCT	2,061	ADT (+/- docetaxel) vs. ADT (+/- docetaxel) with prostate RT	OS	OS difference not significant overall (HR 0.92, 95% CI 0.80-1.06). Subgroup analysis showed significant benefit in OS for those with low metastatic burden (HR 0.68, 95% CI 0.52-0.9; p=0.007)*	G3 or G4 in 5% of patients
HORRAD	De novo metastatic disease	Any metastatic burden	Phase III RCT	432	ADT alone vs. ADT with prostate RT	OS	OS difference not significant (HR=0.90, 95% CI 0.70-1.14)	Not reported
SABR-COMET	ORD	1-5 metastases	Phase II RCT	99**	MDT vs. Standard of care for their respective malignancies	OS	OS improved in MDT arm (5-year OS 42.3% vs. 17.7%, p=0.006)	G5 in 4.5% of patients
STOMP	ORD	≤ 3 metastases	Phase II RCT	62	MDT vs. Observation	ADT-free survival	Median ADT-free survival improved in MDT arm (5-year ADT-free survival 34% vs. 8%, p=0.06)	No G2 or higher
ORIOLE	ORD	≤ 3 metastases	Phase II RCT	54	MDT vs. Observation	Rate of disease progression at 6 months	Disease progression was improved in MDT cohort (Progression at 6 months 19% vs. 61%, p=0.005)	No G3 or higher toxicities
Glicksman et al.	ORD	No limit	Single-arm Phase II Trial	37	PSMA-PET-guided MDT with SBRT or surgery, without ADT	Biochemical response	60% overall response rate with 22% having complete response	No G3 or higher toxicities
Kneebone et al.	ORD	1-3 nodal or bone metastases	Single-arm Phase II Clinical Trial	57	SBRT to metastatic sites without ADT	Biochemical failure***	At median follow up of 16 months, median bDFS was 11 months, with 31.9% bDFS at 15 months	No G3 or higher
Siva et al.	ORD	1-3 nodal or bone metastases	Feasibility Study	33	One fraction of SBRT to each lesion	Feasibility and tolerability	All but one patient completed the prescribed dose to metastatic sites	One patient with G3
Pezzulla et al.	OPD	≤ 5 non-visceral, nodal metastases	Post hoc analysis of phase I clinical trials	38	SBRT to lesions (in addition to concurrent ADT)	Biochemical response and toxicity	2-year next line systemic therapy-free survival of 67.7%	One patient with > G1

*Defined as not having visceral metastases or ≥4 bone metastases with at least one outside of the spine/pelvis.

**N=16 with prostate cancer.

***PSA level of nadir +0.2ng/mL following MDT.

RCT, randomized controlled trial; ADT, androgen deprivation therapy; OS, overall survival; OMD, oligometastatic disease; RT, radiotherapy; ORD, oligorecurrent disease; MDT, metastasis-directed therapy; SBRT, stereotactic body radiotherapy; OPD, oligoprogressive disease; G#, grade #.