The Role of Advanced Imaging in Assessing Response to Definitive Chemoradiation Before Prophylactic Cranial Irradiation in Limited-Stage Small-Cell Lung Cancer

Clin Lung Cancer. 2018 Mar;19(2):e205-e209. doi: 10.1016/j.cllc.2017.10.001. Epub 2017 Oct 12.

Abstract

Introduction: Prophylactic cranial irradiation (PCI) improves survival for small-cell lung cancer (SCLC). Evidence for PCI in limited-stage SCLC largely derives from studies requiring only chest x-ray (CXR) to determine remission status. We analyzed thoracic chemoradiation therapy (TCRT) outcomes according to imaging modality to determine which patients benefitted most from PCI.

Patients and methods: All limited-stage SCLC patients who received TCRT as well as PCI at our institution were reviewed. Imaging between TCRT end and PCI start was characterized as complete (CR), partial (PR), or other response.

Results: Thirty-eight consecutive patients were assessed for TCRT response before PCI with CXR (n = 21), chest computed tomography (CT; n = 27), and/or positron emission tomography (PET)/CT (n = 11). CR was identified on 71% of CXRs, 41% of CT scans, and 18% of PET/CT scans. Median survival was 28.3 months for the entire cohort and did not differ for patients who had CXR alone versus CT and/or PET/CT for restaging (P = .78) or those with PR using any modality versus CR using all modalities (22.6 months vs. 45.5 months; P = .22). CT CR patients had numerical but not statistically significant improved 2-year (P = .18) and 3-year (P = .13) survival compared with CT PR.

Conclusion: CXR remains an appropriate modality to assess TCRT response before PCI in limited-stage SCLC. Advanced imaging did not inform the decision to offer PCI in this study. Because of similar excellent survival profiles independent of imaging modality and TCRT response, this analysis suggests limited-stage SCLC patients with PR using any modality should not be denied PCI, akin to standards for extensive-stage SCLC.

Keywords: Chest x-ray; Computed tomography; Partial response; Positron emission tomography; Thoracic chemoradiation.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinogenesis
  • Chemoradiotherapy*
  • Cohort Studies
  • Cranial Irradiation
  • Diagnostic Imaging / methods*
  • Female
  • Humans
  • Lung / diagnostic imaging*
  • Lung Neoplasms / diagnosis*
  • Lung Neoplasms / mortality
  • Lung Neoplasms / therapy
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Positron Emission Tomography Computed Tomography
  • Small Cell Lung Carcinoma / diagnosis*
  • Small Cell Lung Carcinoma / mortality
  • Small Cell Lung Carcinoma / therapy
  • Survival Analysis