Top Line: Radiation is increasingly utilized in treating oligometastatic cancer. This study asks why stop at 5 sites of oligometastatic disease?
The Study: Oligometastatic cancer is classically thought of as a state of disease intermediate between purely localized disease and widespread systemic metastasis. We’re still learning how best to define this state, though, and it likely differs among cancer types. Currently, most definitions use an upper limit of 5 sites of disease to define the oligometastatic state. However, there are trials exploring the use of local therapy for an increasing number of metastatic sites. This phase 1 dose escalation trial explored the feasibility of using SABR to treat all disease in patients with >10 sites of disease. It was small and accrued 13 patients with 207 metastatic sites. Most had colorectal or breast primary tumors. The most common treatment sites were the lungs (26%), lymph nodes (22%), and bones (19%), and the number of treated sites ranged from 11 to 27. They received increasing total doses ranging from 12 Gy in 2 fractions to 30 Gy in 5 fractions. Toxicity was low with 15% experiencing grade 2 toxicity, 7.7% experiencing grade 3 toxicity, and none experiencing grade 4-5 toxicity. The study was designed to assess toxicity rather than efficacy, and most patients (62%) had disease progression with a median PFS of 3.6 months. The obvious next questions are whether such an approach improves outcomes and which patients or types of disease benefit most.
TBL: This small trial found relatively low toxicity when using low-dose SBRT to treat >10 sites of metastatic disease. | Nguyen, Int J Radiat Oncol Biol Phys 2024
The Study: Oligometastatic cancer is classically thought of as a state of disease intermediate between purely localized disease and widespread systemic metastasis. We’re still learning how best to define this state, though, and it likely differs among cancer types. Currently, most definitions use an upper limit of 5 sites of disease to define the oligometastatic state. However, there are trials exploring the use of local therapy for an increasing number of metastatic sites. This phase 1 dose escalation trial explored the feasibility of using SABR to treat all disease in patients with >10 sites of disease. It was small and accrued 13 patients with 207 metastatic sites. Most had colorectal or breast primary tumors. The most common treatment sites were the lungs (26%), lymph nodes (22%), and bones (19%), and the number of treated sites ranged from 11 to 27. They received increasing total doses ranging from 12 Gy in 2 fractions to 30 Gy in 5 fractions. Toxicity was low with 15% experiencing grade 2 toxicity, 7.7% experiencing grade 3 toxicity, and none experiencing grade 4-5 toxicity. The study was designed to assess toxicity rather than efficacy, and most patients (62%) had disease progression with a median PFS of 3.6 months. The obvious next questions are whether such an approach improves outcomes and which patients or types of disease benefit most.
TBL: This small trial found relatively low toxicity when using low-dose SBRT to treat >10 sites of metastatic disease. | Nguyen, Int J Radiat Oncol Biol Phys 2024