Stereotactic body radiation controlled inoperable lung cancer tumors

WASHINGTON — A two-week course of stereotactic body radiation therapy — a type of potent, highly focused radiation — produced high rates of tumor control and may improve survival for patients with inoperable early-stage non–small cell lung cancer.

Robert Timmerman, MD, professor of radiation oncology with the University of Texas Southwestern Medical Center in Dallas, presented results from the RTOG 0236 trial during a press conference at the National Press Center. Full study results were published as part of a Journal of the American Medical Association theme issue on cancer.

In RTOG 0236, 55 patients with T1-T2N0M0 NSCLC and medical conditions that would not allow surgery were assigned up to two weeks of radiotherapy. Patients received 54 Gy of radiation administered in three 18 Gy doses.

“With technology allowing us to localize the dose just to the tumor with little exposure to surrounding tissue, we’re able to give big daily doses,” Timmerman told HemOnc Today. “That turns out to be much more tumoricidal than conventional radiation.”

At three years, the primary tumor control rate was 98% (95% CI, 84%-100%), with a 90.7% local control rate and an 87.2% locoregional control rate. Eleven patients had disseminated recurrence with a three-year disseminated failure rate of 22.1% (95% CI, 12%-38%).

DFS was 48% (95% CI, 34%-61%) and OS was 56% (95% CI, 42%-68%) with median survival of 48.1 months.

Two patients experienced treatment-related grade-4 adverse events, and seven patients had grade-3 treatment-related adverse events. Timmerman said research suggests that patients recovered from this type of injury more quickly than they did with conventional radiation therapy.

“The fear would be that we would injure the patient with these big daily doses. In somewhat of a surprise to us, the treatment was fairly well-tolerated,” he said. “What it means is that patients are able to heal damage if the injury is confined to a small area. It is more difficult for patients to recover from more diffuse injury. Again, somewhat to our surprise, so long as the injury is confined to a small shell around the tumor, patients lose some organ reserve but often recover after three to six months, implying that they’re recovering from that damage.”

Timmerman said RTOG is considering follow-up studies to explain the high rate of disseminated failure observed after treatment, determine a safe and effective dose for central lung tumors and refine the dose of stereotactic body radiation therapy for peripheral tumors. – by Jason Harris

The question that remains to be answered is whether this should be standard of care, or are there patients for whom this treatment is inappropriate. That has to be answered by a trial comparing this sort of care in patients who have a different category of tumor and see if it makes a difference. I can’t answer that question right now. I don’t think anyone can.

– Catherine D. DeAngelis, MD, MPH

Editor-in-Chief, Journal of the American Medical Association, Chicago

Timmerman R. JAMA. 2010;303:1070-1076.

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