NO ROLE FOR TUMOR ABLATION IN THE ERA OF STEREOTACTIC BODY RADIATION FOR STAGE I LUNG CANCER Bryan Meyers MD MPH Washington University School of Medicine
THE PLAYERS Stereotactic body radiation therapy Cyberknife, SBRT, SABR Image guided tumor ablation Radiofrequency ablation (RFA) Microwave ablation Cryotherapy ablation Laser
SPECIFIC SELLING POINTS FOR IGTA Selective damage Minimal morbidity and mortality Lung Sparing Repeatable Relatively low costs Good image guidance Minimal impact on HRQOL
GROUNDS FOR COMPARISON Efficacy Overall survival, disease free survival Local control Cost Availability Patient experience
EFFICACY #1 219 papers were found, of which 16 represented the best evidence to answer the clinical question Radiofrequency ablation (RFA) and stereotactic ablative radiotherapy (SABR) offer a clear survival benefit compared with conventional radiotherapy 5-year survival was higher in SABR (47%) than RFA (20.1 27%) Local progression rates were lower in patients treated with SABR (3.5 14.5% vs. 23.7 43%) Interactive CardioVascular and Thoracic Surgery 15 (2012) 258 265
EFFICACY #2 We conclude that, on the whole, the 23 retrieved studies clearly support the use of stereotactic ablative therapy rather than RF in patients suffering from primary NSCLC unfit for surgery Stereotactic ablative therapy offered a 5-year local control rate varying between 83 and 89.5%, whereas the local control rate after RF ranges from 58 to 68% Interactive CardioVascular and Thoracic Surgery 16 (2013) 68 73
COST Some estimates suggest that IGTA is far cheaper that stereotactic radiation therapy The veracity of such estimates depend on your time horizon and how you amortize the capital costs Treatment short-term costs SBRT $14,700 RFA $5,800 Costs and QALY for typical course (load in other costs for other care) $44,648/1.45 QALY $51,133/1.91 QALY
COST-EFFECTIVENESS The incremental cost-effectiveness ratio for SBRT over 3D-CRT was $6,000/quality-adjusted life-year The incremental cost-effectiveness ratio for SBRT over RFA was $14,100/quality-adjusted life-year If all three treatment options are available to the clinician SBRT is clearly the most cost-effective treatment SBRT should be the primary reimbursed therapy for these tumors in medically compromised individuals, except in those with very small peripheral lesions that may be successfully ablated by RFA Int. J. Radiation Oncology Biol. Phys., Vol. 81, No. 5, pp. e767 e774, 2011
PATIENT EXPERIENCE The post-interventional morbidity was superior for RF ranging from 33 to 100% (mainly composed by pneumothorax), whereas radiation pneumonitis and rib fracture, ranging, respectively, from 3 to 38% and 1.6 to 4%, were the primary complications following stereotactic ablative therapy IGTA complications are immediate or early SBRT complications are delayed No specific comparative effectiveness
AVAILABILITY IGTA is not constrained by the large frame that is required for stereotactic radiation therapy IGTA does not require radioactivity and is therefore much more nimble and portable Many specialists are potentially qualified to perform IGTA including interventional radiology, interventional pulmonary medicine, surgery Despite all the above, SBRT is readily available and the degree to which it is available is increasing
CAN INTERVENTIONAL RADIOLOGY COMPETE? SBRT is currently the national leader based on the plethora of research during the past decade showing excellent local control and improved survival compared with older radiation therapy techniques Tumor ablation will always be considered a fallback treatment option without a greater push by the interventional radiology community to create and fund multi-center trials. Dupuy: J VascIntervRadiol2013;24:1139 1145 http://dx.doi.org/10.1016/j.jvir.2013.04.021
EXCEPTIONS TO CONSIDER? Medical systems in which SBRT is not attainable Redo treatment after failed SBRT in inoperable patients Future projections in which biopsy and treatment take place in same setting, possibly through bronchoscopic approach
AUDIENCE RESPONSE QUESTION When comparing SBRT to IGTA, what is the biggest barrier to making a thorough and unbiased comparison? a. The population of patients treated are notably different from each other b. There is a lack of comparative effectiveness research surrounding IGTA c. The numerous approaches for IGTA (RFA, microwave, cryotherapy) make it difficult to accurately compare to SBRT d. Both technologies are changing so rapidly that a comparison is a moving target and thus likely to be inaccurate