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Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT

BACKGROUND: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMAPET/CT) is a new and evolving diagnostic method in prostate cancer with special impact on treatment planning in image-guided radiotherapy (IGRT). Initial results of metabolic response in repeated PSM...

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Autores principales: Baumann, René, Koncz, Mark, Luetzen, Ulf, Krause, Fabian, Dunst, Juergen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5869895/
https://www.ncbi.nlm.nih.gov/pubmed/29181556
http://dx.doi.org/10.1007/s00066-017-1239-1
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author Baumann, René
Koncz, Mark
Luetzen, Ulf
Krause, Fabian
Dunst, Juergen
author_facet Baumann, René
Koncz, Mark
Luetzen, Ulf
Krause, Fabian
Dunst, Juergen
author_sort Baumann, René
collection PubMed
description BACKGROUND: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMAPET/CT) is a new and evolving diagnostic method in prostate cancer with special impact on treatment planning in image-guided radiotherapy (IGRT). Initial results of metabolic response in repeated PSMA PET/CTs after hypofractionated IGRT for metastatic lesions are reported here. MATERIALS AND METHODS: Of 280 patients investigated with (68)Ga-PSMA PET/CT in the period from 01/2014 through 12/2016 in the authors’ department, patients were selected according to the following criteria: oligometastatic disease at initial PSMA PET/CT defined as not more than five metastatic lesions, hypofractionated IGRT to all lesions, no systemic therapy in the last 6 months and during follow-up, and at least one follow-up PSMA PET after radiotherapy. Radiotherapy was administered to all PSMA PET-detected lesions (CTV = PET-GTV + 1 to 2 mm), mostly with 35 Gy in five fractions (one lesion with four fractions of 7 Gy due to dose constraints, two lymph nodes with 50 Gy in 25 fractions to an extended volume plus a boost of 7 Gy × 2 to the PET-positive volume). Metabolic response of irradiated lesions was evaluated on repeated PSMA PET/CTs according to PERCIST criteria. Five patients with a total number of 12 PSMA PETs matched the criteria. Patients received radiotherapy to all PET-positive lesions and had at least one (in one case three) follow-up PSMA PET examinations after radiotherapy with an interval to the first PET of 2–15 months; the median follow-up for all patients was 11 months. RESULTS: The mean prostate-specific antigen (PSA) values at the time of examination were 8.9 ± 8.5 ng/ml (median 3.3 ng/ml, range 0.17–21.8 ng/ml). A total number of 18 metastatic deposits were detected. The PET-positive tumor volume was 5.9 ± 13.3 cm(3) (median 1.25 cm(3)). The mean standardized uptake value (mean SUV(max)) of the 18 metastatic lesions decreased from 19.9 ± 23.3 (mean ± SD) prior to RT to 5.4 ± 4.6 at post-radiotherapy PSMA PET/CT. Using PERCIST criteria, 14 lesions (78%) showed a metabolic response in PSMA PET with a reduction of SUV of at least 30%, as well as a significant decrease in lesion size; in seven of these lesions, no uptake of (68)Ga-PSMA was detectable. In follow-up PET scans, only two lesions showed metabolic progression with an increase in SUV(max) yielding a local progression-free survival of 88% after 1 year. There was a correlation between the time interval after radiotherapy (median 3 months, range 1–9 months) and response (p = 0.04) with better metabolic response after longer follow-up. CONCLUSIONS: Preliminary results of this study show high metabolic response rates of PSMA PET-positive metastatic lesions after hypofractionated radiotherapy in follow-up PSMA PET with promising local control rates. An interval of several months may be required to fully estimate the efficacy of radiotherapy in control PSMA PET.
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spelling pubmed-58698952018-03-28 Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT Baumann, René Koncz, Mark Luetzen, Ulf Krause, Fabian Dunst, Juergen Strahlenther Onkol Original Article BACKGROUND: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMAPET/CT) is a new and evolving diagnostic method in prostate cancer with special impact on treatment planning in image-guided radiotherapy (IGRT). Initial results of metabolic response in repeated PSMA PET/CTs after hypofractionated IGRT for metastatic lesions are reported here. MATERIALS AND METHODS: Of 280 patients investigated with (68)Ga-PSMA PET/CT in the period from 01/2014 through 12/2016 in the authors’ department, patients were selected according to the following criteria: oligometastatic disease at initial PSMA PET/CT defined as not more than five metastatic lesions, hypofractionated IGRT to all lesions, no systemic therapy in the last 6 months and during follow-up, and at least one follow-up PSMA PET after radiotherapy. Radiotherapy was administered to all PSMA PET-detected lesions (CTV = PET-GTV + 1 to 2 mm), mostly with 35 Gy in five fractions (one lesion with four fractions of 7 Gy due to dose constraints, two lymph nodes with 50 Gy in 25 fractions to an extended volume plus a boost of 7 Gy × 2 to the PET-positive volume). Metabolic response of irradiated lesions was evaluated on repeated PSMA PET/CTs according to PERCIST criteria. Five patients with a total number of 12 PSMA PETs matched the criteria. Patients received radiotherapy to all PET-positive lesions and had at least one (in one case three) follow-up PSMA PET examinations after radiotherapy with an interval to the first PET of 2–15 months; the median follow-up for all patients was 11 months. RESULTS: The mean prostate-specific antigen (PSA) values at the time of examination were 8.9 ± 8.5 ng/ml (median 3.3 ng/ml, range 0.17–21.8 ng/ml). A total number of 18 metastatic deposits were detected. The PET-positive tumor volume was 5.9 ± 13.3 cm(3) (median 1.25 cm(3)). The mean standardized uptake value (mean SUV(max)) of the 18 metastatic lesions decreased from 19.9 ± 23.3 (mean ± SD) prior to RT to 5.4 ± 4.6 at post-radiotherapy PSMA PET/CT. Using PERCIST criteria, 14 lesions (78%) showed a metabolic response in PSMA PET with a reduction of SUV of at least 30%, as well as a significant decrease in lesion size; in seven of these lesions, no uptake of (68)Ga-PSMA was detectable. In follow-up PET scans, only two lesions showed metabolic progression with an increase in SUV(max) yielding a local progression-free survival of 88% after 1 year. There was a correlation between the time interval after radiotherapy (median 3 months, range 1–9 months) and response (p = 0.04) with better metabolic response after longer follow-up. CONCLUSIONS: Preliminary results of this study show high metabolic response rates of PSMA PET-positive metastatic lesions after hypofractionated radiotherapy in follow-up PSMA PET with promising local control rates. An interval of several months may be required to fully estimate the efficacy of radiotherapy in control PSMA PET. Springer Berlin Heidelberg 2017-11-27 2018 /pmc/articles/PMC5869895/ /pubmed/29181556 http://dx.doi.org/10.1007/s00066-017-1239-1 Text en © The Author(s) 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Original Article
Baumann, René
Koncz, Mark
Luetzen, Ulf
Krause, Fabian
Dunst, Juergen
Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT
title Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT
title_full Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT
title_fullStr Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT
title_full_unstemmed Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT
title_short Oligometastases in prostate cancer: Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT
title_sort oligometastases in prostate cancer: metabolic response in follow-up psma-pet-cts after hypofractionated igrt
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5869895/
https://www.ncbi.nlm.nih.gov/pubmed/29181556
http://dx.doi.org/10.1007/s00066-017-1239-1
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