PHILADELPHIA (May 6, 2020)—A study by researchers at Fox Chase Cancer Center has investigated which tumor factors increase the risk of a patient’s cancer spreading to other areas of the body following treatment with stereotactic body radiation therapy (SBRT) alone in patients with lung cancer.
SBRT is localized high-dose radiation that is administered to a tumor in a few treatments. According to Sameera Kumar, MD, an assistant professor in the Department of Radiation Oncology at Fox Chase and one of the study’s authors, data from other studies has shown that decreases in tumor size using SBRT rival that of surgery, with local control rates of over 90 percent.
“However, if you look at the data, there were still patients who would fail with this treatment, either in the lymph nodes or distantly. This study is looking at our patients that have received stereotactic body radiation and looking at predictors of why they fail,” said Kumar.
The retrospective study focused on 174 patients with stage I non-small cell lung cancer who underwent SBRT without another therapy between 2005 and 2016. The median age of the patients was 75.
The results of the analysis showed that patients who experienced cancer in other parts of the body—known as distant metastasis—following SBRT had worse overall survival versus patients developing a regional recurrence. Additionally, patients with larger tumors and tumors in the middle or lower lobes had an increased risk of distant metastasis following SBRT.
“There are other studies that have similar findings. They’ve been done in the stereotactic body radiation therapy and surgical populations. This finding of middle and lower lobe is less common. We don’t know why that is the case, but it is an interesting finding,” said Kumar.
She added that the results provide a clearer picture of which patients could benefit from therapy after radiation by providing a better assessment of who is most at risk for recurrence.
“When you’re looking at another therapy you have to think about the side effects or costs. That’s why we wanted to pick those people who would benefit the most,” said Kumar. “It highlights a population that may need adjuvant treatment such as chemotherapy, immunotherapy, or a targeted agent after they receive SBRT.”
Although the study provides more insight into the risks for patients after SBRT, randomized controlled trials are still needed to further identify patients who may benefit from these therapies, said Kumar.
The study, "Predictors of Distant Recurrence Following Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer"