Long-Term Follow-Up on NRG Oncology RTOG 0915 (NCCTG N0927): A Randomized Phase 2 Study Comparing 2 Stereotactic Body Radiation Therapy Schedules for Medically Inoperable Patients with Stage I Peripheral Non–small Cell Lung Cancer

Abstract

Materials/Methods: Forty-two EC patients were enrolled in this ongoing prospective imaging study. For this report, we report on the 20 patients who had surgery after neoadjuvant CRT. Outcome was assessed pathologically based on tumor regression grade (TRG, 1 Z pathologic complete response, 2 Z near complete response, and 3 Z more than minimal residual). FDG PET imaging was acquired before treatment (baseline, BL), approximately 2 weeks after starting chemoradiation (interim, IM), and at first follow-up (FU) 4-6 weeks after completing CRT. The 3D tumor was contoured on the PET images using gradient edge technique using MIM software (MIM Software Inc. Cleveland, OH). Summary statistics for SUVmax, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were determined from the contoured volume at each time point. Relative changes in each tumor PET parameter from BL to IM and FU scan were calculated and compared by outcome status defined as TRG1 vs. TRG2/TRG3 using Wilcoxon rank-sum test. Multiple logistic regression was used to evaluate receiver operating curve (ROC) characteristics for predicting pathologic response status based on analysis of DSUVmax, DSUVmean, DMTV, and DTLG values. Results: TRG 1, 2, and 3 after CRT and surgery were seen in 5 (29%), 9 (43%), and 6 pts (29%), respectively. Tumors that had a complete pathologic response exhibited significantly greater change in TLG (P Z 0.0117) from the baseline to interim scan, with a threshold of 59% decrease. Change in SUVmax (P Z 0.232, P Z 0.832), SUVmean (P Z 0.086, P Z 0.550), and MTV from BL to IM or BL to FU scans were not predictive of pathologic CR, respectively. Predicting outcome status based on change in TLG at the IM scan yielded AUROC of 0.888 (95% CI: 0.742-1.000). Youden's optimal sensitivity (specificity) were 1.000 (0.813) for DTLG at the IM scan. Conclusion: Our results indicate that DTLG on PET imaging after 2 weeks of CRT may predict pathologic complete response in esophageal cancer. Early response assessment with FDG-PET is potentially useful for stratification of EC pts to treatment intensification or non-surgical management.

FFF‐VMAT for SBRT of lung lesions: Improves dose coverage at tumor‐lung interface compared to flattened beams

“…Due to the recent technological advances in lung stereotactic body radiation therapy (SBRT) treatments and reported comparable tumor local‐control rates,single‐dose lung SBRT has become a viable treatment option for peripherally located lung lesions for medically inoperable early‐stage nonsmall‐cell lung cancer (NSCLC) patients . Additionally, there has been growing interest in the clinical use of flattening filter‐free (FFF) beams to deliver lung SBRT treatment .…”

Flattening filter free VMAT for a stereotactic, single‐dose of 30 Gy to lung lesion in a 15‐min treatment slot

“…The use of single‐fraction lung SBRT treatments has been previously studied . For instance, Siva et al reported comparable local control rates, overall survival and toxicity profiles between single dose of 26 Gy for peripheral tumors and 18 Gy for centrally located tumors compared to 48 Gy in 4 fractions for peripheral tumors and 50 Gy in 5 fractions for the central tumors for patients with FDG‐PET staged pulmonary oligometastases.…”

“…SBRT protocol RTOG‐0915 (Arm 1) allowed a single dose of 34 Gy treatment for early stage I peripheral NSCLC patients when dosimetric criteria were achieved . Videtic et al reported long‐term follow‐up data, which revealed no excess late toxicity in either arm (34 Gy in 1 fraction and 48 Gy in 4 fractions), coupled with consistent high rates of local control. The median overall survival of 4 yr for each arm suggests similar efficacy.…”

A simple, yet novel hybrid‐dynamic conformal arc therapy planning via flattening filter‐free beam for lung stereotactic body radiotherapy

“…[1][2][3][4][5] For the selected peripherally located NSCLC patients; single-dose of SBRT has become a curative treatment option as shown by the randomized trials. [6][7][8][9][10][11][12][13] For instance, Videtic and colleagues 7 compared 2 single-fraction SBRT dosing schemes of 30 and 34 Gy for 80 medically inoperable early stage-I NSCLC patients. Both treatment schedules provided similar tumor local-control and overall survival rates with minimal pulmonary toxicity.…”