Single Fraction SBRT Appropriate for Long-Term Use in Inoperable Early Stage NSCLC

A long-term follow-up study to a clinical trial that compared single treatment versus multiple treatment stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC) patients with potentially curable but inoperable tumors has found that patients continue to do well with either regimen.

“After four years, cancer control is still excellent in each group and treatment-related side effects remain very low in both,” says Gregory Videtic, MD, Director of Thoracic Radiation Oncology at Cleveland Clinic Cancer Center. Dr. Videtic led the clinical trial RTOG 0915 that is now the subject of this follow-up study. Dr. Videtic will present the results of his follow-up study at the ASTRO 2017 annual meeting.

Trial compared 1 vs. 4 treatments

For the original trial, Dr. Videtic and colleagues enrolled medically inoperable patients with Stage I peripheral NSCLC. The patients were randomly assigned so that half the group was treated with 34 Gy in one session and half had lung SBRT as 48 Gy in four fractions over four days.

The initial trial results had shown that although both treatments were equally effective and safe after one year, the single treatment group had a somewhat lower rate of minor side effects. It also indicated that physicians could now recommend just one treatment for patients who fit the trial demographics.

Since that single “shot” approach to lung SBRT was based on a short-term follow-up study, some physicians might have hesitated to apply it to their own patients, says Dr. Videtic. “People will often say, ‘Those are great results, but one year is a relatively short time to understand how treatments work. What about five years or six years out, will you still see the same cure rate? And just as important, are you going to see the same complication rates?’”

The patient population in the trial and follow-up is a complex group to treat, says Dr. Videtic. “Although we want to cure all of their cancer, these patients have other significant medical issues affecting their longevity. So after five years of follow-up, the number of patients remaining alive is rather small. What remains reassuring is they’re not dying primarily of cancer but more likely of conditions such as emphysema or COPD.”

With the current follow-up results, he says, “Single-fraction lung SBRT has now been shown to be as safe and effective as initially reported and therefore appropriate to offer routine patients with tumors similar to those in the study. The long-term results should reassure physicians that if they’re presented with a patient similar to those in the trial, they can make the recommendation for a single session regimen based on mature data.”

SBRT research young but growing

Dr. Videtic says SBRT is still a young discipline and long-term, prospective studies like this one are just now being published. “We’re feeling more comfortable about using different regimens because we’re testing them in a forward-looking way.”

Photo Credit:©Russell Lee