18 F-FDG PET-CT during chemo-radiotherapy in patients with non-small cell lung cancer: the early metabolic response correlates with the delivered radiation dose
To evaluate the metabolic changes on 18 F-fluoro-2-deoxyglucose positron emission tomography integrated with computed tomography ( 18 F-FDG PET-CT) performed before, during and after concurrent chemo-radiotherapy in patients with locally advanced non-small cell lung cancer (NSCLC); to correlate the metabolic response with the delivered radiation dose and with the clinical outcome. Methods Twenty-five NSCLC patients candidates for concurrent chemo-radiotherapy underwent 18 F-FDG PET-CT before treatment (pre-RT PET-CT), during the third week (during-RT PET-CT) of chemo-radiotherapy, and 4 weeks from the end of chemo-radiotherapy (post-RT PET-CT). The parameters evaluated were: the maximum standardized uptake value (SUVmax) of the primary tumor, the SUVmax of the lymph nodes, and the Metabolic Tumor Volume (MTV). Results SUVmax of the tumor and MTV significantly (p=0.0001, p=0.002, respectively) decreased earlier during the third week of chemo-radiotherapy, with a further reduction 4 weeks from the end of treatment (p<0.0000, p<0.0002, respectively). SUVmax of lymph nodes showed a trend towards a reduction during chemo-radiotherapy (p=0.06) and decreased significantly (p=0.0006) at the end of treatment. There was a significant correlation (r=0.53, p=0.001) between SUVmax of the tumor measured at during-RT PET-CT and the total dose of radiotherapy reached at the moment of the scan. Disease progression free survival was significantly (p=0.01) longer in patients with complete metabolic response measured at post-RT PET-CT. Conclusions In patients with locally advanced NSCLC, 18 F-FDG PET-CT performed during and after treatment allows early metabolic modifications to be detected, and for this SUVmax is the more sensitive parameter. Further studies are needed to investigate the correlation between the metabolic modifications during therapy and the clinical outcome in order to optimize the therapeutic strategy. Since the metabolic activity during chemo-radiotherapy correlates with the cumulative dose of fractionated radiotherapy delivered at the moment of the scan, special attention should be paid to methodological aspects, such as the radiation dose reached at the time of PET.
R E S E A R C HOpen Access 18 FFDG PETCT during chemoradiotherapy in patients with nonsmall cell lung cancer: the early metabolic response correlates with the delivered radiation dose 1 3*3 32 Mariangela Massaccesi , Maria Lucia Calcagni, Maria Grazia Spitilli , Fabrizio Cocciolillo , Francesca Pelligrò , 2 13 Lorenzo Bonomo , Vincenzo Valentiniand Alessandro Giordano
Abstract 18 Background:To evaluate the metabolic changes onFfluoro2deoxyglucose positron emission tomography 18 integrated with computed tomography (FFDG PETCT) performed before, during and after concurrent chemo radiotherapy in patients with locally advanced nonsmall cell lung cancer (NSCLC); to correlate the metabolic response with the delivered radiation dose and with the clinical outcome. 18 Methods:Twentyfive NSCLC patients candidates for concurrent chemoradiotherapy underwentFFDG PETCT before treatment (preRT PETCT), during the third week (duringRT PETCT) of chemoradiotherapy, and 4 weeks from the end of chemoradiotherapy (postRT PETCT). The parameters evaluated were: the maximum standardized uptake value (SUVmax) of the primary tumor, the SUVmax of the lymph nodes, and the Metabolic Tumor Volume (MTV). Results:SUVmax of the tumor and MTV significantly (p=0.0001, p=0.002, respectively) decreased earlier during the third week of chemoradiotherapy, with a further reduction 4 weeks from the end of treatment (p<0.0000, p<0.0002, respectively). SUVmax of lymph nodes showed a trend towards a reduction during chemoradiotherapy (p=0.06) and decreased significantly (p=0.0006) at the end of treatment. There was a significant correlation (r=0.53, p=0.001) between SUVmax of the tumor measured at duringRT PETCT and the total dose of radiotherapy reached at the moment of the scan. Disease progression free survival was significantly (p=0.01) longer in patients with complete metabolic response measured at postRT PETCT. 18 Conclusions:In patients with locally advanced NSCLC,FFDG PETCT performed during and after treatment allows early metabolic modifications to be detected, and for this SUVmax is the more sensitive parameter. Further studies are needed to investigate the correlation between the metabolic modifications during therapy and the clinical outcome in order to optimize the therapeutic strategy. Since the metabolic activity during chemo radiotherapy correlates with the cumulative dose of fractionated radiotherapy delivered at the moment of the scan, special attention should be paid to methodological aspects, such as the radiation dose reached at the time of PET. Keywords:18FFDG PETCT, NSCLC, Chemoradiotherapy, Metabolic response
* Correspondence: ml.calcagni@rm.unicatt.it 3 Institutes of Nuclear Medicine, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Rome, Italy Full list of author information is available at the end of the article