Definitive Upfront Stereotactic Ablative Radiotherapy Combined with Image-Guided, Intensity Modulated Radiotherapy (IG-IMRT) or IG-IMRT Alone for Locally Advanced Non-Small Cell Lung Cancer

Abstract

BackgroundImage-guided (IG) intensity-modulated radiotherapy (IMRT) enables maximal tumor margin reduction for the sparing of organs at risk (OARs) when used to treat locally advanced non-small cell lung cancer (NSCLC) with definitive chemo-radiation. It also allows for the incorporation of stereotactic ablative radiotherapy (SABR) into the treatment regimen. Here, we describe our initial experience in combining definitive upfront SABR to the primary lesion with chemo-radiation delivered with conventionally fractionated IG-IMRT to the remaining regional disease; along with clinical outcome following chemo-radiation with conventionally fractionated IG-IMRT alone in the treatment of locally advanced NSCLC.MethodsThe clinical outcome of 29 patients with locally advanced NSCLC who underwent conventionally fractionated IG-IMRT, or definitive upfront SABR followed by IG-IMRT combined with chemotherapy (induction, concurrent, or both) was retrospectively reviewed.ResultsAfter a median follow up of 23.7 months, the median overall survival (OS) and progression-free survival (PFS) were 19.8 and 11.3 months, respectively. The 2 year local, regional, and distant control was 60%, 62%, and 38%, respectively. No local failure was observed in 3 patients following SABR + IG-IMRT while 6/26 patients failed locally following IG-IMRT alone. SABR + IG-IMRT was well tolerated. No ≥ grade 3 radiation-related toxicity was observed.ConclusionDefinitive upfront SABR followed by IG-IMRT in selected patients with locally advanced NSCLC warrants further investigation in future clinical trials, while chemo-radiation with IG-IMRT alone was well tolerated.

Pattern of Local Failure and its Risk Factors of Locally Advanced Non-small Cell Lung Cancer Treated With Concurrent Chemo-radiotherapy

“…If the high radiation doses would be focused only on the exact location of the primary tumor using intensity-modulated or stereotactic ablative radiotherapy (SABR) with image guidance, the extra dosing to organs at risk, such as the heart or mediastinum, could be minimized. For example, Alexander et al have reported the feasibility of definitive image-guided intensity modulated radiotherapy (IMRT) combined with SABR in LA-NSCLC patients to increase the dose to the primary tumor (18). In their report, 40-50 Gy in 4 fractions of SABR were delivered to the primary tumor and 63 Gy in 35 fractions of IMRT were delivered to lymph node target volume.…”

Stereotactic body radiation therapy in unresectable stage III non-small cell lung cancer: A systematic review

“…On the other hand, two retrospective studies reported an inverted sequence associating 4-fraction primary tumor SBRT followed by nodal NFRT. In 3 patients of their larger NSCLC cohort, Chi et al observed neither local failure or death at 2 years, nor G≥3 AE [22]. In patients with small, isolated lesion (GTV, median 6.4cc) distant from the nodal involvement, Kim et al…”

“…All titles and abstracts were retrieved and screened. Among the 28 records selected for full-text eligibility assessment, 18 met inclusion criteria [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] (Figure 1). The characteristics of included studies are summarized in Table 1.…”