BOSTON—There were several presentations at this year's American Society for Radiation Oncology Annual Meeting on the topic of lung cancer that are of interest to the larger community, particularly on the topic of stereotactic body radiation therapy (SBRT) for patients with early-stage non-small-cell lung cancer (NSCLC). I will summarize a few that stood out for me, followed by comments as to why I think they are important.
* Nagata et al from the Japanese Cooperative Oncology Group (JCOG) reported initial results of their Phase II study for patients with inoperable T1N0 NSCLC (JCOG 0403). Between 2004 and 2008, 100 prospectively enrolled patients underwent SBRT across 15 institutions using 48 Gy in four fractions. The three-year overall survival for this inoperable group was 59.9 percent. The three-year local-regional progression-free survival rate was 52.8 percent. Grade 3 or 4 toxicity occurred in 11 (10.6%) and two (1.9%) patients, respectively. There were no Grade 5 events. They compared JCOG 0403 results with published series of conventionally fractionated schedules and estimated an improvement of 20 percent of more in overall survival with SBRT techniques.
These study results are further evidence that the treatment of choice for inoperable peripherally located Stage I lung cancer is SBRT, not conventionally fractionated radiation therapy.
* Senan et al from VU University in The Netherlands presented data from a propensity score-matched analysis comparing use of SBRT with video-assisted thoracoscopic lobectomy (VATS) in Stage I-II NSCLC. Patients undergoing each procedure were matched using clinical TNM staging, gender, Charlson co-morbidity index, lung function, and performance status. A total of 64 patients were matched for each group and compared. SBRT had better local-regional control at one and three years (96.8% and 93.3% vs. 86.9% and 82.6%, respectively, p=0.03). The three-year progression-free survival rate did not differ between groups (79.3% and 63.2%, respectively, P=0.09). Distant recurrence rates and overall survival did not differ between groups.
These results show findings similar to those of other published studies comparing SBRT with surgery, meaning that SBRT is at least comparable and may have some advantages. There are two ongoing randomized trials that are attempting to compare SBRT and surgery more scientifically. The results of this trial lend strong support to the current Phase III trials that are accruing slowly within ACOSOG/RTOG and Accuray, Inc.
* Stanic et al presented a secondary analysis from RTOG 0236, the initial study from RTOG showing a 94% lobar local control rate with SBRT. This study looked at the prospectively collected pulmonary function tests (PFTs) obtained pre- and post-SBRT with follow up exams out to two years. PFTs at six months showed mean percentage predicted changes of -0.3%, -6%, and -3.4% in FVC, FEV1, and DLCO, respectively. Similar patterns were seen at three months and two years.
These results are fairly indicative of what would be expected without radiation therapy in the natural history of this population with moderate to severe chronic obstructive pulmonary disease.
* Onishi et al from Japan presented data on 95 patients with lung cancers composed of ≥50% ground-glass opacities (GGOs) treated with SBRT. These patients have been previously excluded from prospective SBRT trials, predominantly due to concern about the difficulty in delineating the lateral extent of these GGOs and the rapid radiation dose-falloff inherent within SBRT techniques. These authors showed that the local control rate at three years was 98.8 percent. The distant failure rate was only 2.6 percent at three years, reflecting the longer localized natural history of these tumors.
Nevertheless, this is one of the first reports to indicate that SBRT is effective for tumors that are predominantly GGOs.
* Finally, Nishimura et al presented the results of a Phase II study using the EGFR monoclonal antibody nimotuzumab in combination with chemoradiation in locally advanced unresectable NSCLC. Nimotuzumab is not available in the United States, but agents with similar mechanisms of action certainly are available. A total of 39 patients received treatment on this single-arm study. These patients were not selected by EGFR-mutation status, though one would expect more patients with EGFR mutations in Japan. The drug was well-tolerated. The two-year overall survival rate was 76 percent. The median PFS was 16.7 months.
The results of this study heighten curiosity about the pending results of RTOG 0617 study, which randomized patients receiving chemoradiation to another EGFR antibody, cetuximab. We may learn more about the results of this important Phase III study in 2013.
© 2013 Lippincott Williams & Wilkins, Inc.