18F-Fludeoxyglucose PET/CT in SCLC: Analysis of the CONVERT Randomized Controlled Trial

J Thorac Oncol. 2019 Jul;14(7):1296-1305. doi: 10.1016/j.jtho.2019.03.023. Epub 2019 Apr 16.

Abstract

Introduction: We used phase-3 CONVERT trial data to investigate the impact of fludeoxyglucose F 18 (18F-FDG) positron emission tomography (PET)/computed tomography (CT) in SCLC.

Methods: CONVERT randomized patients with limited-stage SCLC to twice-daily (45 Gy in 30 fractions) or once-daily (66 Gy in 33 fractions) chemoradiotherapy. Patients were divided into two groups in this unplanned analysis: those staged with conventional imaging (contrast-enhanced thorax and abdomen CT and brain imaging with or without bone scintigraphy) and those staged with 18F-FDG PET/CT in addition.

Results: Data on a total of 540 patients were analyzed. Compared with patients who underwent conventional imaging (n = 231), patients also staged with 18F-FDG PET/CT (n = 309) had a smaller gross tumor volume (p = 0.003), were less likely to have an increased pretreatment serum lactate dehydrogenase level (p = 0.035), and received more chemotherapy (p = 0.026). There were no significant differences in overall (hazard ratio = 0.87, 95% confidence interval: 0.70-1.08, p = 0.192) and progression-free survival (hazard ratio = 0.87, 95% confidence interval: 0.71-1.07], p = 0.198) between patients staged with or without 18F-FDG PET/CT. In the conventional imaging group, we found no survival difference between patients staged with or without bone scintigraphy. Although there were no differences in delivered radiotherapy dose, 18F-FDG PET/CT-staged patients received lower normal tissue (lung, heart, and esophagus) radiation doses. Apart from a higher incidence of late esophagitis in patients staged with conventional imaging (for grade ≥1, 19% versus 11%; [p = 0.012]), the incidence of acute and late radiotherapy-related toxicities was not different between the two groups.

Conclusion: In CONVERT, survival outcomes were not significantly different in patients staged with or without 18F-FDG PET/CT. However, this analysis cannot support the use or omission of 18F-FDG PET/CT owing to study limitations.

Keywords: (18)F-FDG PET/CT; lung cancer; small-cell; staging; survival.

Publication types

  • Clinical Trial, Phase III
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Chemoradiotherapy / mortality*
  • Female
  • Fluorodeoxyglucose F18*
  • Follow-Up Studies
  • Humans
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / pathology*
  • Lung Neoplasms / therapy
  • Male
  • Middle Aged
  • Positron Emission Tomography Computed Tomography / methods*
  • Prognosis
  • Radiopharmaceuticals*
  • Small Cell Lung Carcinoma / diagnostic imaging
  • Small Cell Lung Carcinoma / pathology*
  • Small Cell Lung Carcinoma / therapy
  • Survival Rate

Substances

  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18