The Role of Stereo-tActic BoDy RadIotherApy iN Oligo-Progressive MalignanT Disease

Inclusion criteria

• Adult patients ≥18 years accrued at the Princess Margaret Cancer Centre
• 5 or less sites of intra or extra-cranial oligo-progressive, de novo oligo-metastatic, induced oligo-metastatic and repeat oligo-metastatic breast disease amenable to ablative treatment (including but not limited to radiotherapy, surgery, radio-frequency ablation);

o at least one lesion should be planned for SBRT

• OR 5 or less sites of intra or extra-cranial oligo-progressive prostate, bladder and renal cell carcinomas
• Tumor mass amenable to SABR (≤6cm in size)
• Confirmation of diagnosis:

• Known/documented prior histological (for all excluding HCC) or radiological diagnosis (for HCC) of:
• Pathologically confirmed breast cancer OR,
• Pathologically confirmed GU cancer (such as prostate cancer, bladder cancer, or radiologically or pathologically confirmed RCC).
• For prostate patients only: Known metastatic disease treated with ADT (patients who received other ST as first line treatment of mCSPC would be eligible; eg Docetaxel, Abiraterone…)
• For prostate patients only: Known metastatic CRPC progressing on ST (Docetaxel, Abiraterone, Enzalutamide…)
• For oligo-progressive disease: receiving any form of ST for at least 3 months with (ST breaks are permitted):

• Radiographic evidence of ≤3 intra or extra-cranial lesions progressing (including nodal or distant). At least one lesion is suitable for SBRT. Each progressing lesion should fulfill at least 1 of the 3 following criteria for oligo-progression:

• Progression of a metastasis according to RECIST 1.1 criteria7
• Unambiguous development of a new lesion from the time of scan taken prior to starting ST
• Progressive enlargement of a known metastasis on 2 consecutive imaging (CT or MRI) 2-3 months apart, while on ST, with a minimum 5 mm increase in size from baseline.
• Remainder of metastatic disease stable or regressing, as per RECIST v1.1, evidenced by >2 consecutive images within the past 4-6 months.
• Able to provide written consent
• ECOG performance status 0-3

Exclusion criteria

• ≥6 progressive metastases
• Evidence of spinal cord compression or acute event requiring urgent/emergency radiotherapy
• Prior radiotherapy, with fields overlapping, resulting in excessive doses to organs at risk
• Previous radical RT in the area of OP
• Inability to safely treat all sites of progressing metastases
• Patient cannot tolerate physical set-up required for SBRT
• Treatment plan respecting normal tissue tolerances using dose fractionation specified within the protocol cannot be achieved
• Active bowel obstruction, if treating abdominal/pelvic site
• Neuroendocrine, lymphoma, myeloma or germ cell malignancies
• Familial syndromes: Von Hippel-Lindau disease, Polycystic Kidney Disease, Hereditary Papillary RCC or Tuberous Sclerosis