ESTRO 2024 - Abstract Book

S1578

Clinical - Lung

ESTRO 2024

Analysis of 30- and 90-day mortality after lung SBRT as an indicator for its appropriateness.

Gregory Videtic, Chandana Reddy, Kevin Stephans

Cleveland Clinic, Radiation Oncology, Cleveland, USA

Purpose/Objective:

Lung stereotactic body radiotherapy [SBRT] is the standard of care for curative management of medically inoperable early-stage lung cancer [LUNG-CA] due to its excellent local control and minimal treatment-related toxicity. Competing and/or active patient (pt) co-morbidities at the time of cancer diagnosis may influence decision making regarding SBRT appropriateness. We analyzed 30- and 90-day causes of death (CODs) after SBRT to look for factors which would suggest that the cancer-control benefits of SBRT were lost due to early mortality.

Material/Methods:

We surveyed our institutional review board-approved prospective lung SBRT data registry from 2003 to 2023 for medically inoperable early-stage lung cancer pts to study their CODs within 30 days and 90 days following SBRT. Pts refusing surgical resection or deemed operable, with oligometastases, or treated for salvage were excluded. Selected pre-treatment patient and tumor factors were analyzed using logistic regression analysis to identify factors associated with 90-day mortality.

Results:

For the 20-year interval, 1819 pts met study criteria, with 30.6% alive at analysis. Median follow up was 27.2 months. Patient characteristics included: female (52.9%), median age 74.2 years, median KPS 80. Among causes for pre treatment inoperability, pulmonary [PULM] and cardiovascular [CV] made up 57.8% and 14.5% of the total, respectively. Tumor characteristics included: median size 2.1 cm, median PET SUVmax 7.6, 67% with biopsy proven cancer, 24.4% central. The two most common SBRT schedules employed were 50 Gy/5 fractions (39.7%) and 34 Gy/1 fraction (26.1%). Fifty-four (3.0%) pts died within 90 days of lung SBRT, of which 8 (0.44%) were within 30 days. No deaths were attributable to SBRT. When CODs were grouped by categories, CODs for 30-day and 90-day cohorts (in %) were CV (37.5; 38.9), PULM (12.5; 13.0), LUNG-CA (12.5; 13.0), infectious (25.0; 13.0) and other (12.5; 22.2), respectively. On multivariate analysis, male gender (p= 0.023), lower body-mass index (p=0.0117), higher Charlson score (0.0161), and KPS <80 (p=0.0006) were associated with an increased risk of < 90-day mortality.

Conclusion:

Early deaths after lung SBRT were rare and not associated with the form of treatment or its delivery. CV co morbidities pre-treatment made a minority of early-stage patients medically inoperable. The present analysis suggests CV diagnoses are the most common cause of deaths within 90 days of lung SBRT. Notwithstanding the efficacy and safety of lung SBRT with respect to cancer outcomes, these results suggest attention should be paid to competing CV risk factors when assessing lung SBRT appropriateness.

Keywords: Lung SBRT, mortality, appropriateness