This one time.
Liver mets can sometimes make for that unpleasant conundrum that calls for escalated doses in the setting of sensitive (and mobile) real estate. A bold phase 1 study evaluated escalating doses for liver SBRT in a single, yes single, fraction. The highest established dose was 40 Gy! And here we have long-term results (for 17 liver mets) pooled with a subsequent cohort all receiving 40 Gy x 1 (22 mets). Median lesion size was 2.0 cm, and at least 700 cc of normal liver had to be spared more than 9.1 Gy with 95% of target receiving 100% of prescription and 99% of target 90% prescription. A 4D scan was obtained at sim and target motion limited to less than 1 cm via breath hold, or abdominal compression if needed. A diagnostic MRI for fusion was recommended with a CT at treatment for alignment—fiducials were not required. No grade 3+ toxicities were observed and only 3 of 33 patients had a grade 2 toxicity. What’s more, local control was a whopping 97% at 2 years. TBL: In select patients with liver metastasis, 40 Gy in 1 fraction appears to be a safe and highly effective (and ablative) treatment option. | Folkert, Int J Radiat Oncol Biol Phys 2020