title: Late tumor pseudoprogression followed by complete remission after lung stereotactic ablative radiotherapy.
abstract: Lung stereotactic ablative radiotherapy (SABR) has recently become more common in the management of patients with early-stage non-small cell lung cancer (NSCLC) and metastatic lung lesions who are not surgical candidates. By design, SABR is applied to small treatment volumes, using fewer but significantly higher dose fractions, and steep dose gradients. This treatment theoretically maximizes tumor cell death and decreases the risk of damage to the surrounding normal tissues. Local control rates for SABR in early stage lung cancer remain high. Since the numbers of primary tumor recurrences is small, some debate exists as to the appropriate definition of treatment failure. Controversies remain regarding the most appropriate interpretation of imaging tests obtained to evaluate treatment outcomes after lung SABR. Most definitions of progression include an increasing diameter of target lesion which can be problematic given the known mass-like consolidation seen on CT imaging after ablative therapy. Here, we present a case report illustrative of the pitfalls of relying solely on anatomic imaging to determine SABR treatment failure.
authors.affiliation: Department of Radiation Oncology, MD Anderson Cancer Center, 1515 Holcombe Blvd., Unit 1202, Houston, TX 77030, USA. mstauder@mdanderson.org
authors.forename: Michael C
authors.initials: MC
authors.lastname: Stauder
authors.forename: Jessica W
authors.initials: JW
authors.lastname: Rooney
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Neben-Wittich
authors.forename: Yolanda I
authors.initials: YI
authors.lastname: Garces
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Olivier
mesh_terms: D000368:Aged; D001024:Aortic Valve Stenosis / Q000453:epidemiology; D015897:Comorbidity; D001026:Coronary Artery Bypass; D018450:Disease Progression; D004646:Emphysema / Q000453:epidemiology; D006331:Heart Diseases / Q000453:epidemiology; D006801:Humans; D008171:Lung Diseases / Q000453:epidemiology; D008175:Lung Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D008297:Male; D009203:Myocardial Infarction / Q000453:epidemiology; D016491:Peripheral Vascular Diseases / Q000453:epidemiology; D016634:Radiosurgery; D011880:Radiotherapy Planning, Computer-Assisted; D012074:Remission Induction