A large study by UCLA researchers looking at current practice patterns among doctors treating people with three or more brain metastases — cancer cells that have spread from a primary tumor located in a different part of the body — found significant variation in treatment strategies, bringing to light the need for further research to guide physicians’ decision making.

They also found that there is not enough data to determine which of the two main approaches for treating people that have between three and 10 brain metastases – stereotactic radiosurgery and whole brain radiotherapy – is more effective, although more doctors in an international survey said that stereotactic radiosurgery is their preferred treatment method.

Stereotactic radiosurgery is radiation therapy that precisely targets small brain tumors without damaging healthy tissue. Whole brain radiotherapy involves radiating the entire brain but can cause serious side effects such as decreased cognitive function.

The researchers sent an email survey with questions about patient scenarios and treatment options to more than 5,000 radiation oncologists around the world, and 711 responded. The study determined that whether people received stereotactic radiosurgery or whole brain radiotherapy depended largely upon the institution where they were treated. The authors also determined that further research is needed to determine which treatment method is most beneficial for patients, depending on the number of metastases, they have and once that is known, new guidelines should be written and more visible outreach efforts are needed to inform oncologists about the updated recommendations.

The study was led by Dr. Percy Lee, director of UCLA’s Stereotactic Body Radiation Therapy program. Co–author Dr. Michael Steinberg is a UCLA professor of radiation oncology at the David Geffen School of Medicine at UCLA. Dr. Kiri Sandler and Dr. Narek Shaverdian, co–lead authors, are resident physicians in radiation oncology at UCLA. Co–authors are Dr. Isaac Yang, assistant professor of neurosurgery, Dr. Christopher King, professor of radiation oncology and Dr. Amar Kishan, chief resident in radiation oncology, all of UCLA. Lee, Steinberg, Yang and King are also members of UCLA’s Jonsson Comprehensive Cancer Center.

The study was published online by the journal Cancer.