Brain Metastasis Radiation Options
Radiation Options to Treat Brain Metastasis: Quick Review of WBR, SRS, and SFRT
Nieder et. al. wrote an easy to understand paper on the management of patients with brain metastases from non-small cell lung cancer and adverse prognostic features: multi-national radiation treatment recommendations are heterogeneous. The authors used data from 17 real patients to request recommendations for treatment from seven different institutions and their tumor boards. The tumor boards were able to recommend one of three options: WBR (whole-brain radiation), SRS (stereotactic single-fraction radiation), SFRT (stereotactic fractionated radiotherapy), or supportive care (nothing). From the study, WBR was not recommended frequently. In contrast, SRS/SFRT were the treatments most often recommended.
So, what is WBR? Whole-brain radiation is when the entire brain is subjected to radiation, usually requiring 10 to 15 treatments over two to three weeks. Some side effects may be fatigue, nausea, hair loss, and decline of cognitive functions. The main problem of cognitive function disruption is very real and severe for patients. There are several strategies such as use of supplemental medication or regional sparing (hippocampus sparing).
SRS and SFRT are very similar to WBR with the difference that they entail a directed combination of beams at a specific location in the brain. The side effects are similar to WBR, except the cognitive function disruption is less than WBR. In SFRT, the radiation beams are fractionated or cut to smaller packets to direct the beam toward the cancer. It is very similar to SRS in that sense.
A more recent paper written by Singh et. al, compiled studies of brain metastases from NSCLC with EGFR or ALK mutations from multiple institutions. They looked at 2649 patients with NSCLC that had brain progression. The patients with EGFR or ALK did well when compared to other non-EFGF or non-ALK patients. They measured the success rate by the OS (overall survival) or PFS (progression-free survival). The OS of a patient was not determined by whether the patient had TKI plus radiation therapy or radiation therapy alone. In addition, the PFS was not affected by whether the treatment was WBR, WBR + TKI, SRS, or SRS + TKI. WBR had a PFS of 24 months and SRS was about 15 months. This paper was published Feb. 2020 but the data was collected from before 2019.
https://www.sciencedirect.com/science/article/pii/S0167814019334760
Does that mean WBR is obsolete? No. There is a real value to using WBR such as in the case of small cell lung cancer. It is still one of the treatments recommended for SCLC patients. It is now called prophylactic cranial irradiation (PCI).
However, WBR is no longer recommended by the American Cancer Society for NSCLC patients.
More information at:
https://www.cancer.org/cancer/lung-cancer/treating-small-cell.html
https://www.cancer.org/cancer/lung-cancer/treating-non-small-cell/radiation-therapy.html
This is what the machine may look like.
https://www.mayoclinic.org/diseases-conditions/brain-metastases/diagnosis-treatment/drc-20350140