Oncologic Outcomes of Surgery Versus SBRT for Non-Small-Cell Lung Carcinoma: A Systematic Review and Meta-analysis.

BACKGROUND: The optimal treatment of stage I non-small-cell lung carcinoma is subject to debate. The aim of this study was to compare overall survival and oncologic outcomes of lobar resection (LR), sublobar resection (SR), and stereotactic body radiotherapy (SBRT). METHODS: A systematic review and meta-analysis of oncologic outcomes of propensity matched comparative and noncomparative cohort studies was performed. Outcomes of interest were overall survival and disease-free survival. The inverse variance method and the random-effects method for meta-analysis were utilized to assess the pooled estimates. RESULTS: A total of 100 studies with patients treated for clinical stage I non-small-cell lung carcinoma were included. Long-term overall and disease-free survival after LR was superior over SBRT in all comparisons, and for most comparisons, SR was superior to SBRT. Noncomparative studies showed superior long-term overall and disease-free survival for both LR and SR over SBRT. Although the papers were heterogeneous and of low quality, results remained essentially the same throughout a large number of stratifications and sensitivity analyses. CONCLUSION: Results of this systematic review and meta-analysis showed that LR has superior outcomes compared to SBRT for cI non-small-cell lung carcinoma. New trials are underway evaluating long-term results of SBRT in potentially operable patients.

[Biologic effects of high doses per fraction]. / Effets biologiques des hautes doses par fraction.

The radiobiological concepts described for conventional doses per fraction (1.8 to 2Gy) seem difficult to translate to high doses per fraction radiobiology. In fact, specific mechanisms are involved during high dose per fraction irradiation, involving vascular microenvironment damage and anti tumor immune response. The "5R's" of "classical" radiobiology (factors influencing the response of healthy or cancer cells to irradiation) seem to play a less important role in case of high doses per fraction. In addition, applicability of the linear quadratic model in this context is debated. It is therefore difficult to obtain reliable equivalent doses, hence the importance of including our patients in clinical trials, especially in case of concomitant systemic treatments. In addition to stereotactic radiotherapy, flash irradiations defined by a dose rate approximately 2000 times faster than "conventional" irradiation can also deliver high doses per fraction, with a much better tolerance for normal tissue without loss of anti tumor efficacy. Finally, availability of robust prospective data is a prerequisite to answer the question of short and long-term risk/benefit ratio of these different irradiation techniques.

Impact of the American Tax Payer Relief Act on stereotactic radiosurgery utilization in the United States.

INTRODUCTION: Single-fraction stereotactic radiosurgery (SRS) is delivered predominantly via two modalities: Gamma Knife, and linear accelerator (LINAC). Implementation of the American Tax Payer Relief Act (ATRA) in 2013 represented the first time limitations specifically targeting SRS reimbursement were introduced into federal law. The subsequent impact of the ATRA on SRS utilization in the United States (US) has yet to be examined. METHODS: The National Cancer Database from 2010-2016 identified brain metastases patients from non-small cell lung cancer throughout the US having undergone SRS. Utilization between GKRS and LINAC was assessed before (2010-2012), during (2013-2014) and after (2015-2016) ATRA implementation. RESULTS: In 2013, there was a substantial decrease of LINAC SRS in favor of GKRS in non-academic centers. Over the 3-year span immediately preceding ATRA implementation, 39% of all eligible SRS cases received LINAC. There was a modest decrease in LINAC utilization over the 2 years immediately following ATRA implementation (35%), followed by an increase over the next two years (40%). SRS modality showed differences over the three time periods (unadjusted, p = 0.043), primarily in non-academic centers (unadjusted, p = 0.003). CONCLUSIONS: ATRA implementation in 2013 caused an initial spike in Gamma Knife SRS utilization, followed by a decline to rates similar to the years before implementation. These findings indicate that the ATRA provision mandating Medicare reduction of outpatient payment rates for Gamma Knife to be equivalent with those of LINAC SRS had a significant short-term impact on the radiosurgical treatment of metastatic brain disease throughout the US, serving as a reminder of the importance/impact of public policy on treatment modality utilization by physicians and hospitals.