STEREOTACTIC BODY RADIOTHERAPY VERSUS SURGERY FOR MEDICALLY OPERABLE STAGE I NON-SMALL CELL LUNG CANCER: A MARKOV MODEL BASED DECISION ANALYSIS

Monday, October 25, 2010
Sheraton Hall E/F (Sheraton Centre Toronto Hotel)
Malek B. Hannouf, BSc1, Alexander V. Louie, BSc, MD2, George B. Rodrigues, MD, FRCPC, MSc2, David A. Palma, BSc, MD2, Jeffrey Q. Cao, MD2, Brian P. Yaremko, MSc, PEng, MD2, Richard Malthaner, MSc, MD2, Joseph D. Mocanu, PhD1 and Greg Zaric, Ph.D1, (1)University of Western Ontario, London, ON, Canada, (2)London Regional Cancer Program, London, ON, Canada

Purpose:  To compare the quality-adjusted life expectancy and overall survival in patients with stage I non-small cell lung cancer (NSCLC) treated with either stereotactic body radiation (SBRT) or surgery.

Method: We constructed a Markov model to simulate the clinical history of a cohort of patients with stage I NSCLC that undergo either SBRT or lobectomy for a 5-year timeframe. Rates of recurrence and Markov state utilities, consistent with the four stages of the AJCC staging system, were extracted and adapted from the literature.  Rates of death from all other causes were extracted from standard life tables from the Centre for Disease Control and Prevention (CDC). We report various treatment strategy survival outcomes stratified by age, sex, and pack-year history of smoking and compared these to an external outcome prediction tool commonly used by clinicians: Adjuvant! Online.  

Result: Overall survival, cancer specific survival, and other causes of death as predicted by our model correlated closely with those predicted by Adjuvant! Online. Mean quality-adjusted life expectancy ranged from 3.28 to 3.78 years after surgery and 3.35 to 3.87 years for SBRT. Differences in QALYs for all patient cohorts ranged from 0.07-0.09. The utility threshold for preferring SBRT over surgery was 0.90. Outcomes were sensitive to quality of life, the proportion of local and regional recurrences treated with standard versus palliative treatments, and the surgical and SBRT treatment related mortalities.

Conclusion: The role of SBRT in the medically operable patient is yet to be defined.  Our model indicates that SBRT may offer comparable overall survival and quality adjusted life expectancy as compared to surgical resection.  Well powered prospective studies comparing surgery versus SBRT in early lung cancer are warranted to further investigate the relative survival, quality of life and cost characteristics of both treatment paradigms.