Conformal Radiation for Stage III Non-small Cell Lung Cancer in the. Medicare .... Purpose/Objective(s): The practice of treating a solitary pulmonary nodule (SPN) suspicious for stage I NSCLC with stereotactic ablative radiation therapy ...
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301 Comparative Effectiveness of Intensity-Modulated Versus 3D Conformal Radiation for Stage III Non-small Cell Lung Cancer in the Medicare Population A.B. Chen, L. Li, A. Cronin, and D. Schrag; Dana-Farber Cancer Institute, Boston, MA Purpose/Objective(s): The clinical benefit of intensity-modulated (IMRT) compared to 3D conformal radiation (3D-RT) has not been wellestablished for locally advanced non-small cell lung cancer (NSCLC). We evaluated trends in use of IMRT for stage III lung NSCLC and compared survival and hospitalization outcomes. Materials/Methods: Using SEER-Medicare data, we identified use of IMRT or 3D-RT among 7061 Medicare beneficiaries diagnosed with stage III NSCLC from 2002-2009. Factors associated with use of IMRT versus 3D-RT were identified using multivariable logistic regression. Overall survival and number of hospital days within 90 days of radiation were analyzed using Cox proportional hazard and negative binomial regression models, respectively. Propensity score adjustment was used to control for clinical and demographic variables. Results: IMRT comprised an increasing proportion of conformal treatments for NSCLC, rising from 3.0% in 2002 to 26.8% in 2009. Patients treated at freestanding versus hospital-based facilities were twice as likely to receive IMRT (17.3% vs 9.5%, adj OR Z 2.0, p < 0.01). IMRT use varied by region, with higher rates in the South (12.8%, adj OR Z 1.13) and West (14.2%, adj OR Z 1.25), compared to the Northeast (9.9%, ref) and Midwest (9.1%, adj OR Z 0.88) (overall p Z 0.03) and in urban versus rural areas (12.5% vs 9.9%, adj OR Z 1.52, p < 0.01). Patients with more comorbidities were more likely to receive IMRT, 11.3% (ref) vs 11.7% (adj OR Z 1.03) vs 14.7% (adj OR Z 1.35) for modified Charlson score 0, 1, and 2+, respectively (overall p Z 0.03). We did not find a difference in IMRT use between stage IIIA and stage IIIB patients (11.8% vs 12.4%, adj OR Z 1.11, p Z 0.19). Patients receiving chemotherapy were more likely to receive IMRT (12.8% vs 10.4%, adj OR Z 1.24, p Z 0.02), though there was no difference in IMRT use among patients having surgery (11.4% vs 12.2%, adj OR Z 0.95, p Z 0.68). With propensity score adjustment, IMRTwas associated with greater overall survival (adj HR Z 0.91, p Z 0.03) compared to 3D-RT, though there was no difference in survival among patients receiving at least 25 fractions of radiation (adj HR Z 0.99, p Z 0.83). There was no significant difference in number of hospital days in the 90 days following radiation start (mean 5 days, adj HR Z 1.01, p Z 0.89). Conclusions: When radiation is used to treat locally advanced NSCLC, IMRT is increasingly preferred to 3D-RT. However, among patients receiving potentially curative radiation ( 25 fractions) there was no significant difference in overall survival or time spent hospitalized following treatment compared to 3D-RT. Author Disclosure: A.B. Chen: None. L. Li: None. A. Cronin: None. D. Schrag: None.
302 Comparative Effectiveness of Stereotactic Body Radiation Therapy Versus Surgery for Stage I Non-small Cell Lung Cancer J.B. Yu,1 P.R. Soulos,2 L.D. Cramer,2 R.H. Decker,2 A.W. Kim,3 and C.P. Gross1; 1Yale University School of Medicine, New Haven, CT, 2 Yale University, New Haven, CT, 3Department of Thoracic Surgery, Yale University, New Haven, CT Purpose/Objective(s): Stereotactic body radiation therapy (SBRT) has emerged since 2003 as an effective non-invasive alternative to surgery for elderly patients who are medically inoperable or refuse surgery. More recently, improved clinical staging and treatment techniques may have increased SBRT effectiveness, but potential diffusion of SBRT to sicker patients may have had the opposite effect. Furthermore, the comparative and temporal pattern of toxicity for these treatments is unknown. Therefore, we compared survival and toxicity for patients who underwent SBRT or surgery for stage I non-small cell lung cancer (NSCLC) from 2007-2009 in the Surveillance, Epidemiology, and End Results - Medicare database.
International Journal of Radiation Oncology Biology Physics Materials/Methods: We identified patients age > 67 who had undergone SBRT or surgery for stage I NSCLC from 2007-2009. Patient and regional characteristics were recorded, including a claims-based disability score and comorbidity index. We matched each SBRT patient to 2 surgery patients using propensity scores. Relevant administrative diagnostic and procedure codes were assigned to 6 categories of toxicity: 1) pneumonia, 2) abscess or wound infection, 3) respiratory, 4) cardiovascular, 5) esophageal, or 6) radiationspecific. Rates of lung cancer specific and overall mortality, and trends in toxicity were compared using Poisson regression. Results: There were 367 SBRT patients matched to 711 surgery patients. The 1, 3 and 6 month overall mortality was higher for surgery (2.9%, 5.8%, and 8.9%, respectively) vs. SBRT (1.4%, 2.2%, and 7.3%, respectively). However, at 12 and 24 months overall mortality was higher for SBRT (17.6% and 38.4%) compared to surgery (13.7% and 21.0%). After adjusting for clinical and sociodemographic factors, there was a higher overall mortality for SBRT compared to surgery (incidence rate ratio [IRR] 1.72 [95% CI Z 1.37-2.15]). Patients undergoing SBRT also had higher lung cancer specific mortality (IRR Z1.56 [95% CI Z 1.04-2.34]). Short term toxicity (0-3 months) from surgery was much higher than SBRT (55.8% vs. 7.9%, p < 0.001). At 24 months posttreatment, toxicity from surgery was still higher, although the difference between surgery and SBRT had decreased (79.6% vs. 69.7%, IRR for SBRT vs. surgery 0.70 [95% CI Z 0.60-0.82]). This pattern was largely due to the increased incidence of short term infections and respiratory complications associated with surgery. Conclusions: Although SBRT was associated with lower overall and cancer specific mortality than surgery during the first few months after treatment, by one-year post-treatment this finding was reversed. Overall, there was a significantly lower rate of toxicity for SBRT compared to surgery, largely due to differences in the 0-3 month period. The impact of pathologic staging versus clinical staging and unmeasured confounding is unknown. Author Disclosure: J.B. Yu: E. Research Grant; 21st Century Oncology. P.R. Soulos: None. L.D. Cramer: None. R.H. Decker: None. A.W. Kim: None. C.P. Gross: E. Research Grant; 21st Century Oncology.
303 When is a Biopsy-Proven Diagnosis Necessary Before Stereotactic Ablative Radiation Therapy for Lung Cancer? A Decision Analysis A.V. Louie,1,2 S. Senan,1 P.R. Patel,3 B. Ferket,2 F.J. Lagerwaard,1 G.B. Rodrigues,4 J.K. Salama,3 C.R. Kelsey,3 D.A. Palma,4 and M. Hunink2; 1VU University Medical Center, Amsterdam, Netherlands, 2Harvard School of Public Health, Boston, MA, 3Duke University Affiliated Hospitals, Durham, NC, 4London Regional Cancer Program, London, ON, Canada Purpose/Objective(s): The practice of treating a solitary pulmonary nodule (SPN) suspicious for stage I NSCLC with stereotactic ablative radiation therapy (SABR) in the absence of pathologic confirmation of malignancy is becoming more common. In the absence of randomized evidence, the appropriate lung cancer prevalence threshold of when such a strategy is warranted can be informed using a decision modeling approach. Materials/Methods: A decision tree and Markov model were constructed to evaluate the relative merits of observation, performing SABR without pathology, or performing a biopsy prior to SABR, when faced with a noncalcified SPN > 1 cm in a 75-year old patient at different lung cancer prevalences. Diagnostic characteristics, lung cancer utilities, as well as disease, treatment, and toxicity parameters were extracted from meta-analyses, guideline-based recommendations, and decision analyses. Toxicity and recurrence rates after SABR were obtained from a prospectively collected database of 382 patients receiving SABR for confirmed or suspected stage I NSCLC. As utilities of early stage lung cancer patients treated with SABR have not been well studied, we employed mapping techniques to generate these from another 382 prospective individually-collected EORTC QLQ-C30 quality of life scores in the database. Deterministic sensitivity analyses on all model inputs were performed to inform the appropriate lung cancer prevalence threshold between treatment strategies. The effects of uncertainty in model parameters were evaluated through probabilistic sensitivity analysis (PSA), a technique in which
