Nuklearmedizin 2024; 63(03): 199-206
DOI: 10.1055/a-2284-0593
Original Article

Impact of 68Ga-PSMA PET/CT on radiation treatment planning of prostate cancer patients

Einfluss der 68Ga-PSMA-PET/CT auf die Bestrahlungsplanung beim Prostatakarzinom

Authors

  • Felix Bock

    1   Department of Radiotherapy and Radiation Oncology, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
  • Bernd Frerker

    1   Department of Radiotherapy and Radiation Oncology, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
  • Laura Schubert

    2   Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
  • Hannes Rennau

    1   Department of Radiotherapy and Radiation Oncology, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
  • Jens Kurth

    2   Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
  • Bernd J. Krause

    2   Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
  • Guido Hildebrandt

    1   Department of Radiotherapy and Radiation Oncology, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
  • Sarah Marie Schwarzenböck

    2   Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany (Ringgold ID: RIN39071)
Preview

Abstract

Aim This study aimed to assess the impact of 68Ga-PSMA PET/CT on radiation treatment (RT) planning in prostate cancer patients with salvage (sRT) or definitive (dRT) radiotherapy.

Methods 38 patients (27 sRT, median PSA 0.79 ng/ml (range 0.06–12.1); 11 dRT, median PSA 4.35 ng/ml (range 1.55–55.5) underwent 68Ga-PSMA PET/CT before RT. Influence of 68Ga-PSMA PET/CT on the extent of planning target volume (PTV) and addition of PET-based boosts were assessed. Median follow up was 12 months (range 3–24).

Results 68Ga-PSMA PET/CT showed positive findings in 23/38 patients (8/23: local recurrence (LR), 11/23: nodal metastasis, 1/23: LR and nodal, 2/23: solitary bone metastasis, 1/23: oligometastatic nodal/ bone metastases). In sRT primary PTV was changed in 16/27 patients extending the PTV to the lymphatic drainage (10/16), PSMA-positive LR (3/16), bone metastases (2/16) and both nodal/bone metastases (1/16). PET-based increase of primary PTV was 116%. PET-based boosts were administered in 19/27 patients (8/19: local, 10/19: nodal, 1/19: both), median boost volume was 31.3 cm3 (range 17.2–80.2) (local) and 19.7 cm3 (range 3.0–109.3) (nodal). PTV was changed in 1/11 (9%) of dRT patients (extension of primary PTV to the lymphatic drainage (RT volume of 644.5 cm3), additional nodal boost (volume of 2.7 cm3, 23.1 Gy)). All patients showed biochemical response (mean PSA decrease 88.8 +/– 14.0%). Nadir PSA was reached 10 months (range 1–17) after end of RT (median 0.07 ng/ml, range 0.002–3.96). Within a median 12 months follow-up (range 3–22/8–24 in sRT/dRT), median PSA was 0.05 ng/ml (range 0.002–8.5) (sRT) and 0.26 ng/ml (range 0.02–2.68) (dRT).

Conclusions 68Ga-PSMA PET/CT influenced sRT planning in almost 63% and dRT in 9% of patients by change of PTV and additional boosts.



Publication History

Received: 02 November 2023

Accepted after revision: 08 March 2024

Article published online:
05 April 2024

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