Five is alive.
Top Line: Five-fraction radiation is coming to soft tissue sarcoma.
The Studies: Here we have a report on the long-term outcomes of 16 patients treated on two phase 2 trials of pre-operative radiation of 35-40 Gy delivered over 5 fractions to soft tissue sarcomas of the leg (n=12), arm (n=3) and trunk (n=1). Treatments were delivered every other day, and most received 35 Gy with the exception of deep targets where skin dose wasn’t much of an issue. All patients had fiducials, but they could be external if the tumor was palpable. Of note, the clinical target volume margins were quite small, ranging from 0.2-0.5 cm radially and 2.5-3 cm along tissue planes, and 0.5 cm bolus was used at the discretion of the physician. Median tumor size was 6.7 cm (range 2.4-14 cm). 15 of 16 patients proceeded to surgery, with one grade 3+ toxicity—a grade 4 flap necrosis and tendon contracture requiring surgical revision. At a median of nearly 5 years, there has been one local recurrence and five distant recurrences, on par with historical control rates.
TBL: This data supports larger studies of ultra-hypofractionation of pre-op radiation for soft tissue sarcoma to determine if outcomes are equivalent to more protracted courses but with an obvious convenience factor. | Kubicek, Adv Radiat Oncol 2021