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18F-FDG PET during stereotactic body radiotherapy for stage I lung tumours cannot predict outcome: a pilot study.

Wiegman EM, Pruim J, Ubbels JF, Groen HJ, Langendijk JA, Widder J - Eur. J. Nucl. Med. Mol. Imaging (2011)

Bottom Line: After the first fraction, median SUV(max) increased from 6.7 to 8.1 (p = 0.07) and median SUV(70%) increased from 5.7 to 7.1 (p = 0.05).At 12 weeks, both median SUV(max) and median SUV(70%) decreased by 63% to 3.1 (p = 0.008) and to 2.5 (p = 0.008), respectively.SUV increased during treatment, possibly due to radiation-induced inflammation.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands. E.M.Wiegman@rt.umcg.nl

ABSTRACT

Purpose: (18)F-Fluorodeoxyglucose positron emission tomography (FDG PET) has been used to assess metabolic response several months after stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer. However, whether a metabolic response can be observed already during treatment and thus can be used to predict treatment outcome is undetermined.

Methods: Ten medically inoperable patients with FDG PET-positive lung tumours were included. SBRT consisted of three fractions of 20 Gy delivered at the 80% isodose at days 1, 6 and 11. FDG PET was performed before, on day 6 immediately prior to administration of the second fraction of SBRT and 12 weeks after completion of SBRT. Tumour metabolism was assessed semi-quantitatively using the maximum standardized uptake value (SUV(max)) and SUV(70%).

Results: After the first fraction, median SUV(max) increased from 6.7 to 8.1 (p = 0.07) and median SUV(70%) increased from 5.7 to 7.1 (p = 0.05). At 12 weeks, both median SUV(max) and median SUV(70%) decreased by 63% to 3.1 (p = 0.008) and to 2.5 (p = 0.008), respectively.

Conclusion: SUV increased during treatment, possibly due to radiation-induced inflammation. Therefore, it is unlikely that (18)F-FDG PET during SBRT will predict treatment success.

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Related in: MedlinePlus

Absolute SUVmax before, after the first fraction and 12 weeks after completion of SBRT. SUVmax increased after the first fraction (p = 0.07) and decreased significantly 12 weeks after SBRT (p = 0.008)
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Fig1: Absolute SUVmax before, after the first fraction and 12 weeks after completion of SBRT. SUVmax increased after the first fraction (p = 0.07) and decreased significantly 12 weeks after SBRT (p = 0.008)

Mentions: Prior to SBRT, median SUVmax was 6.7 (range 4.1–24.8) and median SUV70% was 5.7 (range 3.4–20.0). After the first fraction, median SUVmax increased to 8.1 (p = 0.07) (Fig. 1) and median SUV70% increased to 7.1 (p = 0.05), representing a relative increase of 18 and 21%, respectively. At 12 weeks, a metabolic response was observed in all evaluable patients (n = 9). Four patients showed a complete metabolic response (CMR) (44%) and five patients showed a partial metabolic response (56%). Both SUVmax and SUV70% decreased significantly by 63% (p = 0.008) to 3.1 and 2.5, respectively. CMR was not associated with gross tumour volume (GTV) (p = 0.29) or SUVmax prior to treatment (p = 0.34). Routine CT thorax performed 12 weeks after SBRT showed a partial response in eight patients (80%) and stable disease in two patients (20%). Sequential PET/CT images of patient 3 are presented in Fig. 2.Fig. 1


18F-FDG PET during stereotactic body radiotherapy for stage I lung tumours cannot predict outcome: a pilot study.

Wiegman EM, Pruim J, Ubbels JF, Groen HJ, Langendijk JA, Widder J - Eur. J. Nucl. Med. Mol. Imaging (2011)

Absolute SUVmax before, after the first fraction and 12 weeks after completion of SBRT. SUVmax increased after the first fraction (p = 0.07) and decreased significantly 12 weeks after SBRT (p = 0.008)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3094529&req=5

Fig1: Absolute SUVmax before, after the first fraction and 12 weeks after completion of SBRT. SUVmax increased after the first fraction (p = 0.07) and decreased significantly 12 weeks after SBRT (p = 0.008)
Mentions: Prior to SBRT, median SUVmax was 6.7 (range 4.1–24.8) and median SUV70% was 5.7 (range 3.4–20.0). After the first fraction, median SUVmax increased to 8.1 (p = 0.07) (Fig. 1) and median SUV70% increased to 7.1 (p = 0.05), representing a relative increase of 18 and 21%, respectively. At 12 weeks, a metabolic response was observed in all evaluable patients (n = 9). Four patients showed a complete metabolic response (CMR) (44%) and five patients showed a partial metabolic response (56%). Both SUVmax and SUV70% decreased significantly by 63% (p = 0.008) to 3.1 and 2.5, respectively. CMR was not associated with gross tumour volume (GTV) (p = 0.29) or SUVmax prior to treatment (p = 0.34). Routine CT thorax performed 12 weeks after SBRT showed a partial response in eight patients (80%) and stable disease in two patients (20%). Sequential PET/CT images of patient 3 are presented in Fig. 2.Fig. 1

Bottom Line: After the first fraction, median SUV(max) increased from 6.7 to 8.1 (p = 0.07) and median SUV(70%) increased from 5.7 to 7.1 (p = 0.05).At 12 weeks, both median SUV(max) and median SUV(70%) decreased by 63% to 3.1 (p = 0.008) and to 2.5 (p = 0.008), respectively.SUV increased during treatment, possibly due to radiation-induced inflammation.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands. E.M.Wiegman@rt.umcg.nl

ABSTRACT

Purpose: (18)F-Fluorodeoxyglucose positron emission tomography (FDG PET) has been used to assess metabolic response several months after stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer. However, whether a metabolic response can be observed already during treatment and thus can be used to predict treatment outcome is undetermined.

Methods: Ten medically inoperable patients with FDG PET-positive lung tumours were included. SBRT consisted of three fractions of 20 Gy delivered at the 80% isodose at days 1, 6 and 11. FDG PET was performed before, on day 6 immediately prior to administration of the second fraction of SBRT and 12 weeks after completion of SBRT. Tumour metabolism was assessed semi-quantitatively using the maximum standardized uptake value (SUV(max)) and SUV(70%).

Results: After the first fraction, median SUV(max) increased from 6.7 to 8.1 (p = 0.07) and median SUV(70%) increased from 5.7 to 7.1 (p = 0.05). At 12 weeks, both median SUV(max) and median SUV(70%) decreased by 63% to 3.1 (p = 0.008) and to 2.5 (p = 0.008), respectively.

Conclusion: SUV increased during treatment, possibly due to radiation-induced inflammation. Therefore, it is unlikely that (18)F-FDG PET during SBRT will predict treatment success.

Show MeSH
Related in: MedlinePlus