Majid Z. Janabi MD, Abstract Co-Author: Nothing to Disclose

Nitin Jain MBBS, , Presenter: Nothing to Disclose

Ajay Kumar MD, PhD, Abstract Co-Author: Nothing to Disclose

Anthony Shields MD, PhD, Abstract Co-Author: Research Consultant, General Electric Company Research Consultant, Merck & Co, Inc Research Consultant, Siemens AG Research Consultant, Takeda Pharmaceutical Company Limited Research Consultant, Bristol-Myers Squibb Company Research Consultant, Novartis AG Research Consultant, Alnylam Pharmaceuticals, Inc Research Consultant, sanofi-aventis Group Stockholder, Radiology Corporation of America Research grant, Novartis AG Research grant, Pfizer Inc Research grant, AstraZeneca PLC

James Janisse PhD, Abstract Co-Author: Nothing to Disclose

We conducted a pilot study to determine whether ultra short-term steroid therapy (48 hours) can help in characterizing equivocal pulmonary nodules in FDG PET/CT scan.

So far, eight patients (Age: 40 – 68 yrs; Male: 2, Female: 6) with a total of 11 lesions (benign: 6 and malignant: 5) underwent two PET/CT scans, one at baseline and the second (limited to thorax only) within 10 days of the first scan, after receiving 4 mg dexamethasone at 40, 28, 16 and 4 hours prior to the second scan. Both scans were evaluated separately by two independent investigators both visually, by categorizing the lesions as, i) not changed, ii) increased, or iii) decreased in intensity in second scan compared to the first one, and semi-quantitatively, by calculating the percent change in maximal SUV of the lesions between two scans.

Visual analysis revealed decreased intensity of all the lesions after steroid treatment. Semiquantitative analysis showed decreased maximal SUV after steroid treatment in both benign and malignant lesions; 35% and 31%, respectively. However, there was no statistical or clinical difference in the change in maximal SUV between benign or malignant lesions (p=ns). (Table)

1. Our pilot study with limited sample size indicated that steroid therapy, for 48 hours, is not useful in characterizing equivocal pulmonary nodules in FDG PET/CT scan. 2. It appears that there is an inflammatory reaction associated with pulmonary malignant lesions that responding to the anti-inflammatory effect of the steroid, resulting in decreasing the maximal SUV of about 33%. These findings make us reflect to conduct a larger study to reevaluate the current practice for using PET scan for evaluating the response chemotherapy regimen that includes prednisone. In the current practice, a reduction in the maximal SUV of > 20% after 1st chemotherapy cycle is considered to indicate a good response to the therapy. However, these changes may be related to the effect of prednisone!!

The finding of decreased SUV after steroid therapy may challange the current practice of considering >20% reduction in SUV as a good response to chemotherapy in cancer patients receiving steroids.

Janabi, M, Jain, N, Kumar, A, Shields, A, Janisse, J, Role of Ultra Short-term Steroid Therapy in Characterizing Equivocal Pulmonary Nodules in FDG PET/CT Scan.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11003012.html