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| |  Highly-Focused, Potent Radiation Provides Targeted Tumour Control for Inoperable NSCLC WASHINGTON, DC -- March 16, 2010 -- Early findings suggest a radiation therapy that involves numerous highly-focused and potent radiation beams provides targeted tumour control in nearly all patients, reduces treatment-related illness, and may ultimately improve survival for patients with inoperable non-small cell lung cancer (NSCLC), according to a study published in the March 17 issue of JAMA, a theme issue on cancer. Robert Timmerman, MD, University of Texas Southwestern Medical Center, Dallas, Texas, presented the findings of the study at a JAMA media briefing today. Patients with inoperable early stage lung cancer are generally offered conventional radiation treatment (most commonly given during 20 to 30 outpatient treatments) or observed without specific cancer therapy. “Outcomes are not ideal with either approach,” the authors wrote. “Conventional radiotherapy fails to durably control the primary lung tumour in 60% to 70% of patients. More than half of patients ultimately die specifically from progressive lung cancer with observation, and 2-year survival is less than 40% with either approach.” Stereotactic body radiation therapy (SBRT) is a noninvasive cancer treatment in which numerous small, highly focused, and accurate radiation beams are used to deliver potent doses in 1 to 5 treatments to tumour targets. Dr. Timmerman and colleagues conducted the Radiation Therapy Oncology Group (RTOG) 0236 trial, the first North American multicentre, cooperative group study to test SBRT in treating medically inoperable patients with early stage NSCLC. The Phase 2 study included patients aged 18 years or older with biopsy-proven peripheral T1-T2N0M0 non-small cell tumours (measuring <5 cm. in diameter) and medical conditions that would not allow surgical treatment. Radiation treatment lasted between 1.5 and 2 weeks. The study opened May 2004 and closed October 2006, with data analysed through August 2009. The final study population included 55 patients (44 with T1 tumours and 11 patients with T2 tumours), with a median follow-up of 34.4 months. The primary outcome measured for the study was 2-year actuarial primary tumour control; secondary end points were disease-free survival (ie, primary tumor, involved lobe, regional, and disseminated recurrence), treatment-related toxicity and overall survival. Of all the patients in the study, only 1 experienced a documented tumour recurrence or progression at the primary site. The 3-year primary tumour control rate was 97.6%. Three patients had recurrence within the involved lobe; the 3-year primary tumour and involved lobe control rate was 90.6%. Combining local and regional failures, the 3-year local-regional control rate was 87.2%. Disseminated recurrence as some component of recurrence was reported in 11 patients. The 3-year rate of disseminated failure was 22.1% with 8 such failures occurring prior to 24 months. Disease-free survival and overall survival at 3 years were 48.3% and 55.8%, respectively. Median disease-free survival and overall survival for all patients were 34.4 months and 48.1 months, respectively. Seven patients (12.7%) and 2 patients (3.6%) were reported to experience protocol-specified treatment-related grade 3 and 4 adverse events, respectively. No grade 5 treatment-related adverse events were reported. Higher grades indicate greater severity of adverse event, with grade 5 indicating death. “The main finding in this prospective study was the high rate of primary tumour control (97.6% at 3 years). Primary tumor control is an essential requirement for the cure of lung cancer,” the authors wrote. “Stereotactic body radiation therapy as delivered in RTOG 0236 provided more than double the rate of primary tumour control than previous reports describing conventional radiotherapy.” “The RTOG 0236 trial demonstrated that technologically intensive treatments like SBRT can be performed in a cooperative group so long as the proper infrastructure and support are put in place,” the concluded. “The RTOG will be building on RTOG 0236 to (l) design a trial to address the rather high rate of disseminated failure observed after treatment, (2) complete a trial to determine a safe and effective dose for central lung tumors, and (3) complete a trial to refine the dose of SBRT for peripheral tumours.” SOURCE: JAMA
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