Top Line: Does prophylactic radiation reduce the risk of skeletal events in patients with high risk, but asymptomatic bone metastases?
The Study: At ASTRO 2022, this trial made headlines by showing prophylactic radiation for high risk bone metastases. Now we have the full manuscript. The trial enrolled 78 patients with metastatic cancer, more than 5 sites of metastasis, and at least one asymptomatic, high risk bone metastasis. High risk bone metastases were defined using 4 criteria: 1) any bulky (≥2 cm) metastasis, 2) a metastasis involving the hip, shoulder, or SI joint, 3) a metastasis in a long bone occupying ⅓ or more of the cortical thickness, or 4) metastasis to junction spine or the posterior elements of any part of the spine. This included 122 total treated sites. The most common types of high risk lesions were hip/SI joint (42%), junctional spine (32%), and bulky (20%). Most had lung (27%), breast (24%), or prostate cancer (22%). Patients were randomized to continue standard treatment with or without prophylactic palliative radiation to high risk lesions. Any technique was allowed, and the most frequently used regimens were 27 Gy in 3 fractions, 20 Gy in 5 fractions, 8 Gy in 1 fraction, and 30 Gy in 10 fractions. At 1 year, prophylactic radiation significantly reduced the rate of skeletal related events (1.6% v 29%). SREs were defined as pain requiring palliative radiation, pathologic fracture, spinal cord compression, or surgery. Even when ignoring palliative RT as a SRE, the rate was still lower with prophylactic RT (0% v 12%). There was also a reduction in hospitalizations due to SREs (0% v 11%). The most provocative secondary outcome was significantly longer median OS in the prophylactic arm (1.7 v 1.0 years). But maybe that’s not so provocative. Billions are spent per year on medical therapy to prevent skeletal events and improve survival. Larger trials will determine if reducing SREs with prophylactic radiation truly improves survival.
TBL: In this randomized, phase 2 trial, prophylactic radiation to asymptomatic, high risk bone metastases significantly reduced skeletal events compared to observation and symptomatic treatment. | Gillespie, J Clin Oncol 2023
The Study: At ASTRO 2022, this trial made headlines by showing prophylactic radiation for high risk bone metastases. Now we have the full manuscript. The trial enrolled 78 patients with metastatic cancer, more than 5 sites of metastasis, and at least one asymptomatic, high risk bone metastasis. High risk bone metastases were defined using 4 criteria: 1) any bulky (≥2 cm) metastasis, 2) a metastasis involving the hip, shoulder, or SI joint, 3) a metastasis in a long bone occupying ⅓ or more of the cortical thickness, or 4) metastasis to junction spine or the posterior elements of any part of the spine. This included 122 total treated sites. The most common types of high risk lesions were hip/SI joint (42%), junctional spine (32%), and bulky (20%). Most had lung (27%), breast (24%), or prostate cancer (22%). Patients were randomized to continue standard treatment with or without prophylactic palliative radiation to high risk lesions. Any technique was allowed, and the most frequently used regimens were 27 Gy in 3 fractions, 20 Gy in 5 fractions, 8 Gy in 1 fraction, and 30 Gy in 10 fractions. At 1 year, prophylactic radiation significantly reduced the rate of skeletal related events (1.6% v 29%). SREs were defined as pain requiring palliative radiation, pathologic fracture, spinal cord compression, or surgery. Even when ignoring palliative RT as a SRE, the rate was still lower with prophylactic RT (0% v 12%). There was also a reduction in hospitalizations due to SREs (0% v 11%). The most provocative secondary outcome was significantly longer median OS in the prophylactic arm (1.7 v 1.0 years). But maybe that’s not so provocative. Billions are spent per year on medical therapy to prevent skeletal events and improve survival. Larger trials will determine if reducing SREs with prophylactic radiation truly improves survival.
TBL: In this randomized, phase 2 trial, prophylactic radiation to asymptomatic, high risk bone metastases significantly reduced skeletal events compared to observation and symptomatic treatment. | Gillespie, J Clin Oncol 2023