title: Decreased Lung Perfusion After Breast/Chest Wall Irradiation: Quantitative Results From a Prospective Clinical Trial.
abstract: To quantify lung perfusion changes after breast/chest wall radiation therapy (RT) using pre- and post-RT single photon emission computed tomography/computed tomography (SPECT/CT) attenuation-corrected perfusion scans; and correlate decreased perfusion with adjuvant RT dose for breast cancer in a prospective clinical trial.
  
  
  
  As part of an institutional review board-approved trial studying the impact of RT technique on lung function in node-positive breast cancer, patients received breast/chest wall and regional nodal irradiation including superior internal mammary node RT to 50 to 52.2 Gy with a boost to the tumor bed/mastectomy scar. All patients underwent quantitative SPECT/CT lung perfusion scanning before RT and 1 year after RT. The SPECT/CT scans were co-registered, and the ratio of decreased perfusion after RT relative to the pre-RT perfusion scan was calculated to allow for direct comparison of SPECT/CT perfusion changes with delivered RT dose. The average ratio of decreased perfusion was calculated in 10-Gy dose increments from 0 to 60 Gy.
  
  
  
  Fifty patients had complete lung SPECT/CT perfusion data available. No patient developed symptoms consistent with pulmonary toxicity. Nearly all patients demonstrated decreased perfusion in the left lung according to voxel-based analyses. The average ratio of lung perfusion deficits increased for each 10-Gy increment in radiation dose to the lung, with the largest changes in regions of lung that received 50 to 60 Gy (ratio 0.72 [95% confidence interval 0.64-0.79], P<.001) compared with the 0- to 10-Gy region. For each increase in 10 Gy to the left lung, the lung perfusion ratio decreased by 0.06 (P<.001).
  
  
  
  In the assessment of 50 patients with node-positive breast cancer treated with RT in a prospective clinical trial, decreased lung perfusion by SPECT/CT was demonstrated. Our study allowed for quantification of lung perfusion defects in a prospective cohort of breast cancer patients for whom attenuation-corrected SPECT/CT scans could be registered directly to RT treatment fields for precise dose estimates.
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan. Electronic address: adamliss68@gmail.com.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Liss
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Marsh
authors.affiliation: Department of Radiation Oncology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire.
authors.forename: Nirav S
authors.initials: NS
authors.lastname: Kapadia
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: McShan
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Virginia E
authors.initials: VE
authors.lastname: Rogers
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: James M
authors.initials: JM
authors.lastname: Balter
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Jean M
authors.initials: JM
authors.lastname: Moran
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Kristy K
authors.initials: KK
authors.lastname: Brock
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Matt J
authors.initials: MJ
authors.lastname: Schipper
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Reshma
authors.initials: R
authors.lastname: Jagsi
authors.affiliation: Biostatistics Unit, University of Michigan, Ann Arbor, Michigan.
authors.forename: Kent A
authors.initials: KA
authors.lastname: Griffith
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Flaherty
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Kirk A
authors.initials: KA
authors.lastname: Frey
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Pierce
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology* / Q000528:radiation effects*; D008198:Lymph Nodes / Q000473:pathology; D008408:Mastectomy / Q000706:statistics & numerical data; D015412:Mastectomy, Segmental / Q000706:statistics & numerical data; D008875:Middle Aged; D011184:Postoperative Period; D011446:Prospective Studies; D011829:Radiation Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D015899:Tomography, Emission-Computed, Single-Photon; D000069584:Unilateral Breast Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*
chemical_list: D000970:Antineoplastic Agents