Lung SBRT credentialing in the Canadian OCOG-LUSTRE randomized trial.

Purpose: To report on the Stereotactic Body Radiation Therapy (SBRT) credentialing experience during the Phase III Ontario Clinical Oncology Group (OCOG) LUSTRE trial for stage I non-small cell lung cancer. Methods: Three credentialing requirements were required in this process: (a) An institutional technical survey; (b) IROC (Imaging and Radiation Oncology Core) thoracic phantom end-to-end test; and (c) Contouring and completion of standardized test cases using SBRT for one central and one peripheral lung cancer, compared against the host institution as the standard. The main hypotheses were that unacceptable variation would exist particularly in OAR definition across all centres, and that institutions with limited experience in SBRT would be more likely to violate per-protocol guidelines. Results: Fifteen Canadian centres participated of which 8 were new, and 7 were previously established (≥2 years SBRT experience), and all successfully completed surveys and IROC phantom testing. Of 30 SBRT test plans, 10 required replanning due to major deviations, with no differences in violations between new and established centres (p = 0.61). Mean contouring errors were highest for brachial plexus in the central (C) case (12.55 ± 6.62 mm), and vessels in the peripheral (P) case (13.01 ± 12.55 mm), with the proximal bronchial tree (PBT) (2.82 ± 0.78 C, 3.27 ± 1.06 P) as another variable structure. Mean dice coefficients were lowest for plexus (0.37 ± 0.2 C, 0.37 ± 0.14 P), PBT (0.77 ± 0.06 C, 0.75 ± 0.09 P), vessels (0.69 ± 0.29 C, 0.64 ± 0.31 P), and esophagus (0.74 ± 0.04 C, 0.76 ± 0.04 P). All plans passed per-protocol planning target volume (PTV) coverage and maximum/volumetric organs-at-risk constraints, although variations existed in dose gradients within and outside the target. Conclusions: Clear differences exist in both contouring and planning with lung SBRT, regardless of centre experience. Such an exercise is important for studies that rely on high precision radiotherapy, and to ensure that implications on trial quality and outcomes are as optimal as possible.

Canadian Phase III Randomized Trial of Stereotactic Body Radiotherapy Versus Conventionally Hypofractionated Radiotherapy for Stage I, Medically Inoperable Non-Small-Cell Lung Cancer - Rationale and Protocol Design for the Ontario Clinical Oncology Group (OCOG)-LUSTRE Trial.

We describe a Canadian phase III randomized controlled trial of stereotactic body radiotherapy (SBRT) versus conventionally hypofractionated radiotherapy (CRT) for the treatment of stage I medically inoperable non-small-cell lung cancer (OCOG-LUSTRE Trial). Eligible patients are randomized in a 2:1 fashion to either SBRT (48 Gy in 4 fractions for peripherally located lesions; 60 Gy in 8 fractions for centrally located lesions) or CRT (60 Gy in 15 fractions). The primary outcome of the study is 3-year local control, which we hypothesize will improve from 75% with CRT to 87.5% with SBRT. With 85% power to detect a difference of this magnitude (hazard ratio = 0.46), a 2-sided α = 0.05 and a 2:1 randomization, we require a sample size of 324 patients (216 SBRT, 108 CRT). Important secondary outcomes include overall survival, disease-free survival, toxicity, radiation-related treatment death, quality of life, and cost-effectiveness. A robust radiation therapy quality assurance program has been established to assure consistent and high quality SBRT and CRT delivery. Despite widespread interest and adoption of SBRT, there still remains a concern regarding long-term control and risks of toxicity (particularly in patients with centrally located lesions). The OCOG-LUSTRE study is the only randomized phase III trial testing SBRT in a medically inoperable population, and the results of this trial will attempt to prove that the benefits of SBRT outweigh the potential risks.

A Phase II Trial of Erlotinib and Concurrent Palliative Thoracic Radiation for Patients With Non-Small-Cell Lung Cancer.

BACKGROUND: The downstream signaling pathways of the epidermal growth factor receptor might influence radiation resistance. Data from preclinical work support the hypothesis that erlotinib concurrent with radiation therapy (RT) might increase cancer cell killing. The present trial was designed to examine the efficacy and toxicity of combined erlotinib and palliative chest thoracic RT in non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: Patients with newly diagnosed stage III-IV (American Joint Committee on Cancer, version 6) or recurrent NSCLC received 3 weeks of erlotinib at a dose of 150 mg daily, starting 1 week before palliative thoracic RT to 30 Gy in 10 fractions within 2 weeks. The primary outcome was a change in the quality of life, as measured by the Lung Cancer Symptom Scale (LCSS) question on the "symptoms of lung cancer" from baseline to 4 weeks after treatment. RESULTS: A total of 40 patients were recruited from 2 institutions. Of the 40 patients, 22 (55%) were men, with an average age of 71 years, and 60% had stage IV disease. A total of 26 patients (65%) completed the full course of erlotinib, and 35 (88%) completed the planned RT. Twenty-five patients (62.5%) reported LCSS scores at 4 weeks after treatment, with an average change (improvement) of -12.5 U (95% confidence interval, -23.0 to -1.9; 2P = .023). This was less than the a priori hypothesis of a change of -17.5 U. The median overall and progression-free survival was 5.2 and 3.2 months, respectively. CONCLUSION: The present single-arm, phase II trial did not demonstrate additional symptomatic benefit from concurrent erlotinib therapy with standard palliative thoracic RT for patients with locally advanced or metastatic NSCLC.