Preliminary results on response assessment using (68)Ga-HBED-CC-PSMA PET/CT in patients with metastatic prostate cancer undergoing docetaxel chemotherapy

TY - JOUR

T1 - Preliminary results on response assessment using (68)Ga-HBED-CC-PSMA PET/CT in patients with metastatic prostate cancer undergoing docetaxel chemotherapy

AU - Seitz, A. K.

AU - Rauscher, I.

AU - Haller, B.

AU - Kronke, M.

AU - Luther, S.

AU - Heck, M. M.

AU - Horn, T.

AU - Gschwend, J. E.

AU - Schwaiger, M.

AU - Eiber, M.

AU - Maurer, T.

N1 - 1619-7089 Seitz, Anna Katharina Orcid: 0000-0002-1249-5333 Rauscher, Isabel Haller, Bernhard Kronke, Markus Luther, Sophia Heck, Matthias M Horn, Thomas Gschwend, Jurgen E Schwaiger, Markus Eiber, Matthias Maurer, Tobias SFB 824./Deutsche Forschungsgemeinschaft (DFG)/International Journal Article Germany Eur J Nucl Med Mol Imaging. 2018 Apr;45(4):602-612. doi: 10.1007/s00259-017-3887-x. Epub 2017 Nov 28.

PY - 2018

Y1 - 2018

N2 - PURPOSE: To investigate the value of (68)Ga-HBED-CC PSMA ((68)Ga-PSMA) PET/CT for response assessment in metastatic castration-sensitive and castration-resistant prostate cancer (mCSPC and mCRPC) during docetaxel chemotherapy. METHODS: (68)Ga-PSMA PET/CT was performed in seven mCSPC patients before and after six cycles of upfront docetaxel chemotherapy and in 16 mCRPC patients before and after three cycles of palliative docetaxel chemotherapy. Radiographic treatment response was evaluated separately on the (68)Ga-PSMA PET and CT datasets. Changes in (68)Ga-PSMA uptake (SUVmean) were assessed on a per-patient and a per-lesion basis using the PERCIST scoring system with slight modification. Treatment response was defined as absence of any PSMA uptake in all target lesions on posttreatment PET (complete response, CR) or a decrease in summed SUVmean of >/=30% (partial response, PR). The appearance of a new PET-positive lesion or an increase in summed SUVmean of >/=30% (progressive disease, PD) indicated nonresponse. A moderate change in summed SUVmean (between -30% and +30%) without a change in the number of target lesions was defined as stable disease (SD). For treatment response assessment on CT, RECIST1.1 criteria were used. Radiographic responses on (68)Ga-PSMA PET [RR(PET)] and on CT [RR(CT)] were compared and correlated with biochemical response (BR). A decrease in serum PSA level of >/=50% was defined as biochemical PR. RESULTS: Biochemical PR was found in six of seven patients with mCSPC (86%, 95% confidence interval 42% to 99.6%). The concordance rate was higher between BR and RR(PET) than between BR and RR(CT) (6/7 vs. 3/6 patients. (68)Ga-PSMA PET and CT were concordant in only three patients (50%, 12% to 88%). In mCRPC patients, biochemical PR was found in six of 16 patients (38%, 15% to 65%). Outcome prediction was concordant between BR and RR(PET) in nine of 16 patients (56%), and between BR and RR(CT) in only four of 12 patients (33%) with target lesions on CT. (68)Ga-PSMA PET and CT results corresponded in seven of 12 patients (58%, 28% to 85%). CONCLUSION: Our preliminary results suggest that (68)Ga-PSMA PET might be a promising method for treatment response assessment in mCSPC and mCRPC. The data indicate that for different metastatic sites, the performance of (68)Ga-PSMA PET in response assessment might be superior to that of the conventional CT approach and could help differentiate between progressive disease and treatment response. Because of the limited number of patients, the differences revealed in our study were not statistically significant. Thus larger and prospective studies are clearly needed and warranted to confirm the value of (68)Ga-PSMA PET as an imaging biomarker for response assessment.

AB - PURPOSE: To investigate the value of (68)Ga-HBED-CC PSMA ((68)Ga-PSMA) PET/CT for response assessment in metastatic castration-sensitive and castration-resistant prostate cancer (mCSPC and mCRPC) during docetaxel chemotherapy. METHODS: (68)Ga-PSMA PET/CT was performed in seven mCSPC patients before and after six cycles of upfront docetaxel chemotherapy and in 16 mCRPC patients before and after three cycles of palliative docetaxel chemotherapy. Radiographic treatment response was evaluated separately on the (68)Ga-PSMA PET and CT datasets. Changes in (68)Ga-PSMA uptake (SUVmean) were assessed on a per-patient and a per-lesion basis using the PERCIST scoring system with slight modification. Treatment response was defined as absence of any PSMA uptake in all target lesions on posttreatment PET (complete response, CR) or a decrease in summed SUVmean of >/=30% (partial response, PR). The appearance of a new PET-positive lesion or an increase in summed SUVmean of >/=30% (progressive disease, PD) indicated nonresponse. A moderate change in summed SUVmean (between -30% and +30%) without a change in the number of target lesions was defined as stable disease (SD). For treatment response assessment on CT, RECIST1.1 criteria were used. Radiographic responses on (68)Ga-PSMA PET [RR(PET)] and on CT [RR(CT)] were compared and correlated with biochemical response (BR). A decrease in serum PSA level of >/=50% was defined as biochemical PR. RESULTS: Biochemical PR was found in six of seven patients with mCSPC (86%, 95% confidence interval 42% to 99.6%). The concordance rate was higher between BR and RR(PET) than between BR and RR(CT) (6/7 vs. 3/6 patients. (68)Ga-PSMA PET and CT were concordant in only three patients (50%, 12% to 88%). In mCRPC patients, biochemical PR was found in six of 16 patients (38%, 15% to 65%). Outcome prediction was concordant between BR and RR(PET) in nine of 16 patients (56%), and between BR and RR(CT) in only four of 12 patients (33%) with target lesions on CT. (68)Ga-PSMA PET and CT results corresponded in seven of 12 patients (58%, 28% to 85%). CONCLUSION: Our preliminary results suggest that (68)Ga-PSMA PET might be a promising method for treatment response assessment in mCSPC and mCRPC. The data indicate that for different metastatic sites, the performance of (68)Ga-PSMA PET in response assessment might be superior to that of the conventional CT approach and could help differentiate between progressive disease and treatment response. Because of the limited number of patients, the differences revealed in our study were not statistically significant. Thus larger and prospective studies are clearly needed and warranted to confirm the value of (68)Ga-PSMA PET as an imaging biomarker for response assessment.

KW - Aged Docetaxel/therapeutic use Edetic Acid/analogs & derivatives Humans Male Middle Aged Neoplasm Recurrence, Local Positron Emission Tomography Computed Tomography Prospective Studies Prostatic Neoplasms/diagnostic imaging/drug therapy Radiopharmaceutica

U2 - 10.1007/s00259-017-3887-x

DO - 10.1007/s00259-017-3887-x

M3 - SCORING: Journal article

VL - 45

SP - 602

EP - 612

JO - EUR J NUCL MED MOL I

JF - EUR J NUCL MED MOL I

SN - 1619-7070

IS - 4

ER -