title: Tumor control probability modeling for stereotactic body radiation therapy of early-stage lung cancer using multiple bio-physical models.
abstract: This work is to analyze pooled clinical data using different radiobiological models and to understand the relationship between biologically effective dose (BED) and tumor control probability (TCP) for stereotactic body radiotherapy (SBRT) of early-stage non-small cell lung cancer (NSCLC). The clinical data of 1-, 2-, 3-, and 5-year actuarial or Kaplan-Meier TCP from 46 selected studies were collected for SBRT of NSCLC in the literature. The TCP data were separated for Stage T1 and T2 tumors if possible, otherwise collected for combined stages. BED was calculated at isocenters using six radiobiological models. For each model, the independent model parameters were determined from a fit to the TCP data using the least chi-square (χ2) method with either one set of parameters regardless of tumor stages or two sets for T1 and T2 tumors separately. The fits to the clinic data yield consistent results of large α/β ratios of about 20Gy for all models investigated. The regrowth model that accounts for the tumor repopulation and heterogeneity leads to a better fit to the data, compared to other 5 models where the fits were indistinguishable between the models. The models based on the fitting parameters predict that the T2 tumors require about additional 1Gy physical dose at isocenters per fraction (⩽5 fractions) to achieve the optimal TCP when compared to the T1 tumors. In conclusion, this systematic analysis of a large set of published clinical data using different radiobiological models shows that local TCP for SBRT of early-stage NSCLC has strong dependence on BED with large α/β ratios of about 20Gy. The six models predict that a BED (calculated with α/β of 20) of 90Gy is sufficient to achieve TCP⩾95%. Among the models considered, the regrowth model leads to a better fit to the clinical data.
authors.affiliation: Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, United States.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, United States.
authors.forename: An
authors.initials: A
authors.lastname: Tai
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, United States.
authors.forename: Percy
authors.initials: P
authors.lastname: Lee
authors.affiliation: Department of Radiation Oncology, University Hospitals at Case Western Reserve University, Cleveland, United States.
authors.forename: Tithi
authors.initials: T
authors.lastname: Biswas
authors.affiliation: Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, United States.
authors.forename: George X
authors.initials: GX
authors.lastname: Ding
authors.affiliation: Department of Radiation Oncology, McGill University, Montreal, Canada.
authors.forename: Isaam
authors.initials: I
authors.lastname: El Naqa
authors.affiliation: Holy Redeemer Hospital, Philadelphia, United States.
authors.forename: Jimm
authors.initials: J
authors.lastname: Grimm
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Jackson
authors.affiliation: Department of Radiation Oncology, GRU Cancer Center and Medical School of Georgia, Augusta, United States.
authors.forename: Feng-Ming Spring
authors.initials: FS
authors.lastname: Kong
authors.affiliation: Department of Radiation Oncology, Cooper University Hospital, Camden, United States.
authors.forename: Tamara
authors.initials: T
authors.lastname: LaCouture
authors.affiliation: Department of Radiation Oncology, Stanford Cancer Center, Stanford, United States.
authors.forename: Billy
authors.initials: B
authors.lastname: Loo
authors.affiliation: Department of Radiation Oncology, University of Colorado at Denver, Aurora, United States.
authors.forename: Moyed
authors.initials: M
authors.lastname: Miften
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, United States.
authors.forename: Timothy
authors.initials: T
authors.lastname: Solberg
authors.affiliation: Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, United States. Electronic address: ali@mcw.edu.
authors.forename: X Allen
authors.initials: XA
authors.lastname: Li
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000532:radiotherapy*; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008954:Models, Biological; D009367:Neoplasm Staging; D011336:Probability; D011853:Radiobiology; D016634:Radiosurgery / Q000379:methods
keywords: Early stage non-small cell lung cancer; Stereotactic body radiation therapy; Tumor control probability modeling