A recent study, entitled “Particle beam radiation therapy using carbon ions and protons for oligometastatic lung tumors” published in the August issue of Radiation Oncology, reports that particle beam radiation therapy (PBRT) is a promising, effective treatment against oligometastatic lung tumors.
Oligometastasis is a clinically significant term for metastases, since it stipulates a limited number and location of metastatic instances. Thus, local control of oligometastasis by utilizing localized therapies, such as resection or radiation therapy, is a promising approach.
Particle beam radiation therapy (PBRT), with proton and carbon ion beams, is presumed to deliver a superior dose of treatment to the target location without increasing toxicity to the surrounding non cancerous tissues and organs.
In the present study, the team of scientists analyzed a group of 47 patients with oligometastatic lung tumors (59 lesions) to evaluate the feasibility, efficacy, and toxicity of PBRT against these tumors. The patients were treated with PBRT and followed through 17 months.
The patients’ primary tumors had different locations — colorectum (for 23.4% of the patients), lung (21.3%), and other sites (55.3%). Around 60% of the patients received chemotherapy prior to PBRT.
The authors found that both carbon ion therapy and proton therapy were effective and with tolerable side effects when treating oligometastatic lung tumors. Specifically, at two years, local control rates were 79%, overall survival 54%, and progression-free survival rates of 27%. However, higher rates of overall survival and local control can be achievable with higher PBRT doses (BED10 ≥ 110 GyE10).
These findings are especially relevant because PBRT has the advantage of sparing normal lung tissues and can thus be an alternative to patients with impaired lung functions that cannot undergo surgery.