CT Densitometry and Morphology of Radiofrequency-Ablated Stage IA Non-Small Cell Lung Cancer: Results from the American College of Surgeons Oncology Group Z4033 (Alliance) Trial

J Vasc Interv Radiol. 2020 Feb;31(2):286-293. doi: 10.1016/j.jvir.2019.09.010. Epub 2020 Jan 3.


Purpose: To evaluate tumor and ablation zone morphology and densitometry related to tumor recurrence in participants with Stage IA non-small cell lung cancer undergoing radiofrequency ablation in a prospective, multicenter trial.

Materials and methods: Forty-five participants (median 76 years old; 25 women; 20 men) from 16 sites were followed for 2 years (December 2006 to November 2010) with computed tomography (CT) densitometry. Imaging findings before and after ablation were recorded, including maximum CT attenuation (in Hounsfield units) at precontrast and 45-, 90-, 180-, and 300-s postcontrast.

Results: Every 1-cm increase in the largest axial diameter of the ablation zone at 3-months' follow-up compared to the index tumor reduced the odds of 2-year recurrence by 52% (P = .02). A 1-cm difference performed the best (sensitivity, 0.56; specificity, 0.93; positive likelihood ratio of 8). CT densitometry precontrast and at 45 seconds showed significantly different enhancement patterns in a comparison among pretreated lung cancer (delta = +61.2 HU), tumor recurrence (delta = +57 HU), and treated tumor/ablation zone (delta [change in attenuation] = +16.9 HU), (P < .0001). Densitometry from 45 to 300 s was also different among pretreated tumor (delta = -6.8 HU), recurrence (delta = -11.2 HU), and treated tumor (delta = +12.1 HU; P = .01). Untreated and residual tumor demonstrated washout, whereas treated tumor demonstrated increased attenuation.

Conclusions: An ablation zone ≥1 cm larger than the initial tumor, based on 3-month follow-up imaging, is recommended to decrease odds of recurrence. CT densitometry can delineate tumor versus treatment zones.

Publication types

  • Clinical Trial
  • Multicenter Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Carcinoma, Non-Small-Cell Lung / diagnostic imaging
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Carcinoma, Non-Small-Cell Lung / surgery*
  • Female
  • Humans
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / pathology
  • Lung Neoplasms / surgery*
  • Male
  • Margins of Excision
  • Neoplasm Recurrence, Local
  • Neoplasm Staging
  • Predictive Value of Tests
  • Prospective Studies
  • Radiofrequency Ablation*
  • Risk Factors
  • Time Factors
  • Tomography, X-Ray Computed*
  • Treatment Outcome
  • Tumor Burden
  • United States