2485 - Daily vs. Every-Other-Day Stereotactic Body Radiotherapy for Treatment of Ultra-Central and Central Non-Small Cell Lung Cancer
Presenter(s)
T. Skelly1, B. Elgohari2, F. Li3, J. Park4, N. Mail5, R. J. Lalonde6, M. S. S. Huq6, and T. J. Wilhite7; 1University of Pittsburgh School of Medicine, Pittsburgh, PA, 2MD Anderson Cancer Center, Houston, PA, 3Department of Radiation Oncology, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, 4Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 5upmc, PITTSBURGH, PA, 6Department of Radiation Oncology, UPMC Hillman Cancer Center, Pittsburgh, PA, 7Department of Radiation Oncology, Mayo Clinic, Rochester, MN
Purpose/Objective(s): Stereotactic body radiation therapy (SBRT) is used for treatment of early-stage non-small lung cancer (NSCLC) with comparable results to surgery. Central & ultra-central lesions pose a significant challenge for radiation delivery. We aimed to evaluate safety & efficacy of daily versus every other day SBRT treatment of early-stage NSCLC in terms of oncological & toxicity outcomes.
Materials/Methods: A retrospective chart review was conducted of patients treated for central & ultra-central lung cancer. Two groups were identified: 1) every other day (QoD) SBRT from 2017-2020 with no internal target volume (ITV) generated but gross target volume (GTV) was allowed to receive a boost up to 125% while ensure organ at risk constraints were achieved, and 2) daily (QD) SBRT from 2020-2022 with an ITV generated which received a boost up to 120% of prescribed dose. Demographics, pathology, toxicities, radiotherapy, & outcomes data such as local control (LC), regional control (RC), distant control (DC), & overall survival (OS) were collected.
Results: A total of 120 patients (58 in QoD & 62 in QD group) were included, with a median age at diagnosis of 74 years old (IQR: 68-82). There were 73 females, 36 adenocarcinoma histology, 77 T1 & 41 T2 tumors, 111 had PET/CT, 84 underwent biopsy, median RT dose received was 48 gray, & median number of fractions was 5. The median follow-up for the whole cohort was 27.1 months (IQR: 17.0-39.5). The GTV boost was 114% for QD vs 102% of dose prescription for QoD, (P=0.00). For entire cohort, 2-year OS was 77.1% (95% CI, 69-85), 2-year LC was 83.5% (95% CI 75-93), 2-year RC was 76.6% (95% CI, 58-92), & 2-year DC was 84.8% (95% CI 78-92). For QoD group, 2-year OS was 68.8% (95% CI, 57-81) vs. 82.7% (95% CI, 73 – 93) for QD, (p=0.11), & 2-year LC was 71.7% (95% CI, 52 -91) vs. 84.6% (95% CI 70- 99) for QD, (p=0.28). A significant difference in 2-year RC was found: 68.2% (95% CI, 49 –87) for QoD vs. 94.9% (95% CI, 89 -100) for QD, (p=0.008). No significant difference was observed for DC. An exploratory analysis controlling follow-up to <50 months, a statistically significant difference in 2-year OS was found: 63.1% (95% CI. 48-78) for QoD vs. 84.1% (95% CI. 75-94) for QD, (p= 0.003). A chi-square analysis of toxicities showed no difference between 2 groups. The grade 1 chest wall tenderness (6 QoD vs. 2 QD, p=0.12), grade 1 radiation pneumonitis (5 QoD vs. 2 QD, p=0.19), grade 1 esophagitis (2 QoD, p=0.23), grade 1 bronchopulmonary hemorrhage (2 QoD, p=0.23), grade 1 airway injury (2 QoD, p=0.23), & grade 1 cardiac toxicity (2 QoD, p=0.23). No grade 2 or higher toxicities were observed.
Conclusion: QD treatment showed numerically better clinical outcomes & lower incidence of toxicity than QoD treatment. There is a trend for a better overall survival in patients treated with ITV & received daily treatment with minimal toxicities but longer follow up is needed to confirm this observation. Our data suggest that QD treatment is safe and effective compared to QoD for treatment of ultra-central & central early-stage NSCLC.