Lung Cancer

SS 02 - Lung 1 - SBRT

19 - Systemic Therapy With Stereotactic Body Radiation Therapy (SBRT) for Early-Stage Non-Small Cell Lung Carcinoma (NSCLC): A Multi-institutional Analysis

Sunday, October 21
2:05 PM - 2:15 PM
Location: Room 004

Systemic Therapy With Stereotactic Body Radiation Therapy (SBRT) for Early-Stage Non-Small Cell Lung Carcinoma (NSCLC): A Multi-institutional Analysis
B. H. Kann1, J. A. Miccio1, J. M. Stahl1, V. Verma2, A. Dosoretz3, H. S. M. Park1, T. D. Shafman3, C. P. Gross4, J. B. Yu1, and R. H. Decker1; 1Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT, 2Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE, 321st Century Oncology, Fort Myers, FL, 4Cancer Outcomes, Public Policy, and Effectiveness Research (COPPER) Center, Yale School of Medicine, New Haven, CT

Purpose/Objective(s): For patients with early-stage NSCLC, SBRT generally yields favorable local tumor control, but regional and distant failures occur in up to 20-30% of patients. Although adjuvant systemic therapy (ST) is often recommended for early-stage NSCLC with large tumors after surgery, there is a lack of evidence supporting the use of ST with SBRT. We used a multi-institutional database to evaluate the association between ST use and disease and survival outcomes for patients with early-stage NSCLC treated with SBRT.

Materials/Methods: We conducted a retrospective cohort study using a multi-institutional, academic-community practice database, including consecutive patients with biopsy-proven T1-3N0M0 NSCLC treated with definitive SBRT from 2006 – 2015 at 114 sites. Patient cohorts were defined as those who received SBRT+ST or SBRT alone. Group characteristics were compared with Chi-square, Wilcoxon rank-sum, and logistic regression. Local, regional, and distant failure (LF, RF, and DF) were analyzed with multivariable competing risks regression with Fine and Gray’s proportional subhazards models. Progression-free and overall survival were analyzed with the Kaplan-Meier method and Cox regression. Competing risks regression was performed with 2:1 nearest-neighbor propensity score matching on clinical risk factors.

Results: Of 1,328 patients included, 54 (4.1%) received SBRT+ST. The most common ST regimen was a platinum doublet (n=38; 70.4%), followed by erlotinib (n=8; 14.8%), single agent chemotherapy (n=3; 5.6%), or unknown regimen (n=5; 9.3%). Compared with SBRT patients, SBRT+ST patients were younger (median age: 71 v 78, P<.001), had larger tumors (>2 cm: 38.9% v 21.5%, P=.003), and higher T-stage (T2-3: 42.6% v 22.4%, P=.001). Median follow-up in living patients was 24 months. Compared with the SBRT cohort, the SBRT+ST cohort had significantly less DF (3.7% v 13.0%, P=.04) and RF (0% v 10.4%, P=.01), but not LF (7.4% v 10.4%, P=0.48). On multivariable analyses, SBRT+ST was independently associated with reduced DF (HR: .22, 95%CI: .05 - .88, P=.03) and overall failure (HR: .34, 95%CI: .15 - .76, P=.009) (RF not evaluable, as there were no events in the SBRT+ST cohort), with trend for improved progression-free (HR: 0.72, 95%CI: 0.49 – 1.06, P=.09), but not overall survival (HR: .78, 95%CI: .52 – 1.18, P=.24). After propensity score matching on size, T-stage, performance and smoking status, histology, and age, the SBRT+ST cohort had reduced DF, RF, and overall failure (each P<.05).

Conclusion: This multi-institutional study shows improved regional, distant, and overall disease control in patients receiving adjuvant systemic therapy with SBRT for early stage NSCLC, despite the increased prevalence of larger and higher-stage tumors in this cohort. Prospective study is being planned to evaluate this hypothesis in high-risk subgroups.

Author Disclosure: B.H. Kann: Employee; Yale School of Medicine. J.A. Miccio: None. J.M. Stahl: None. V. Verma: None. T.D. Shafman: None. C.P. Gross: PI; Pfizer. Research Grant; Johnson & Johnson, 21st Century Oncology. J.B. Yu: Research Grant; 21st Century Oncology. Consultant; Augmenix. R.H. Decker: Research Grant; Merck & Co., Inc, Genentech. Advisory Board; Regeneron, AstraZeneca.

Benjamin Kann, MD, BSEE

Disclosure:
Employment
Yale School of Medicine: Assistant Professor: Employee, Resident: Employee

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19 - Systemic Therapy With Stereotactic Body Radiation Therapy (SBRT) for Early-Stage Non-Small Cell Lung Carcinoma (NSCLC): A Multi-institutional Analysis



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