Continued erlotinib maintenance and salvage radiation for solitary areas of disease progression: a useful strategy in selected non-small cell lung cancers?

PURPOSE: Advanced non-small cell lung cancer (NSCLC) is a common and lethal malignancy that has rarely benefited from chemotherapy. Erlotinib is highly effective in NSCLC patients selected by clinical characteristics and/or the presence of epidermal growth factor receptor-sensitizing mutations. However, the way to delay or bypass erlotinib resistance is not systematically addressed. Different erlotinib-failure modes have been reported in NSCLC, and strategies to prolong erlotinib efficacy are perhaps adaptable to them. We report the feasibility and efficacy of continued erlotinib maintenance and local salvage radiation to overcome erlotinib resistances in selected NSCLC patients. PATIENTS AND METHODS: Thirty of 52 consecutive erlotinib-treated advanced NSCLC from the NYU Langone Medical Center and the Arnau de Vilanova Hospital of Lleida responded initially to erlotinib. Twenty-six patients eventually showed a generalized-progression to erlotinib, and four progressed in solitary tumor sites. These four patients were treated with continued erlotinib maintenance and local salvage radiation. RESULTS: The progression-free survival (PFS) was statistically similar in patients with oligo or generalized-progression to erlotinib. However, all four cases with solitary-progression did benefit from continued erlotinib maintenance and salvage radiation with 41-140 % prolongation of PFS. It was reflected in an improved overall survival when they were compared with patients with generalized-progression (76.4 vs. 19.9 months; p = 0.018). CONCLUSION: Continued erlotinib maintenance and local salvage radiation is feasible and could contribute to a better outcome in selected NSCLC patients with solitary-progression to erlotinib. Prospective randomized trials of this strategy are warranted.