Journal Club Treatment Planning Treatment Toxicity

Has SABR hit the safe spot?

SABR Constraints

Ian Pereira, MD and Sara Beltrán Ponce, MD

This weekend we’ll be discussing new guidelines for stereotactic ablative radiation treatment (SABR/SBRT) – from Saturday March 19 to Sunday March 20, 2022.

SABR, or very high doses of radiation per fraction over a smaller number of treatments, has gained immense popularity over the past decade. In the early 2000s, SABR was first used to treat early stage peripheral lung cancers.  Since then, its use expanded to include cancers of the liver (hepatocellular carcinoma or HCC), metastatic cancer that has spread to limited distant sites (‘oligometastases’), among others.

Possible benefits of SABR include decreased treatment time (including less visits for patients), increased potential for cure, and reduced toxicity – if used appropriately.

While landmark positive trials such as SABR-COMET1 have launched enthusiasm, negative trials such as the use in oligometastatic breast cancer2 and reports on its toxicities continue to grow.  Thankfully, the available data on SABR continues to increase, from a few studies at the turn of the century to over 2000 published papers by 2021 along with many ongoing clinical trials.

In an era of person-centered care, shared decision-making, and resource stewardship, do we now have enough data on SABR to offer patients, providers, and their health systems better choices to minimize toxicity while improving cancer-related outcomes?

This weekend, building on our previous HyTec #RadOnc #JC3 we’ll be discussing the new 2022 UK consensus on SABR constraints to shed more light:

Diez, P., et al., UK 2022 Consensus on Normal Tissue Dose-Volume Constraints for Oligometastatic, Primary Lung and Hepatocellular Carcinoma Stereotactic Ablative Radiotherapy. Clinical Oncology, 2022.

#Grateful to be joined by co-authors Drs. Patty Diez Hes (@PattyDiezH), Gerry Hanna (@GerryHanna), Katharine Aitken (@AitkenKatharine), Emma Dunne (@emmadunne), Alison Tree (@AlisonTree), and Louise Murray along with experts Jeff Ryckman (@jryckman3), Chris Estes (@EstesRadonc), and more.

Guiding topics:

T1. Background:
What are common uses of SABR for cancer and why? What are its benefits and risks? What constraints do radiation oncology practices currently use? Why do we need new guidelines, now?

T2. Methods:
How were these SABR guidelines developed? Who was involved, what evidence was considered, and how was consensus achieved?

T3. Results/Discussion:
What were the key findings? How do they compare to previous guidelines?  In what settings are these guidelines applicable?

T4. #PatientsIncluded: From a patient-perspective, what would patients like to know about SABR during each visit (consultation, treatment planning, on treatment, and on follow-up)?

T5. Conclusion/Next steps:
How could these guidelines change SABR clinical practice? Are there gaps that require further study?

Selected References

Open Access & Patient-Focused
1. What is Stereotactic Body Radiation Therapy (SBRT/SABR). Last Accessed March 12, 2022.

2. Oligometastatic Cancer: A More Treatable Kind of Metastatic Cancer? NCI Staff. October 5, 2020. Last Accessed March 12, 2022.

Academic Publications
1.         Palma DA, Olson R, Harrow S, et al. Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers: Long-Term Results of the SABR-COMET Phase II Randomized Trial. J Clin Oncol 2020; 38: 2830-2838. 2020/06/03. DOI: 10.1200/jco.20.00818.

2.         Chmura SJ, Winter KA, Al-Hallaq HA, et al. NRG-BR002: A phase IIR/III trial of standard of care therapy with or without stereotactic body radiotherapy (SBRT) and/or surgical ablation for newly oligometastatic breast cancer (NCT02364557). Journal of Clinical Oncology 2019; 37: TPS1117-TPS1117. DOI: 10.1200/JCO.2019.37.15_suppl.TPS1117.

3.         Katz MS. High Dose, HyTEC – Guidance for Stereotactic and Hypofractionated Radiation Treatment Planning, (2021, accessed August 17, 2021).

4.         Diez P, Hanna GG, Aitken KL, et al. UK 2022 Consensus on Normal Tissue Dose-Volume Constraints for Oligometastatic, Primary Lung and Hepatocellular Carcinoma Stereotactic Ablative Radiotherapy. Clinical Oncology 2022. DOI:

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