Fig. 1

Influence of PSMA-PET/CT results on initially planned treatment decisions for prostate cancer patients. Abbreviations: RT—radiotherapy, ChT—chemotherapy, ADT—androgen deprivation therapy, SBRT—stereotactic body radiation. A Groups of patients with initially planned treatment by radiation oncologist, as it was requested from the urologist. Overall, 43 PCa patients were divided into three groups according to their primary treatment plans: Radical RT group: 48.83% (n = 21) newly diagnosed PCa patients with initial treatment intention radical/curative RT. Salvage RT group: 39.53% (n = 17) PCa patients with biochemical recurrence after radical prostatectomy and initial treatment intention post prostatectomy RT and Oligometastases RT group: 11.9% (n = 5) oligometastatic PCa patients responded to systemic treatment and initial treatment intention RT to the metastases. Due to the lack of recent/present information on disease status, e.g., CT or MRI scans were performed some time ago or never, radiation oncologists initially made treatment plans; then, to confirm that they made the right decisions, they requested a PSMA-PET/CT for each patient before initiating therapy. B Changes in the primary treatment plan after PSMA-PET/CT scan results were observed in every group. In the Radical RT group (n = 21), 33.3% (7/21) proceeded with systemic treatment (ChT, ADT and/or hormonal treatment). 14 pts (14/21) were treated curatively. In 28.6% (6/21) of them, the RT plan was changed and only 38.1% (8/21) went forward as planned. In the Salvage RT group (n = 17), 47% (8/17) of the patients continued with systemic treatment ± RT. 53% (8/15) of the patients treated by RT the RT plan was changed. Only 41% (7/17) of the patients continued as planned. In the Oligometastatic RT group, the majority (60%, 3/5) underwent systemic treatment, and 20% (1/5) and 20% (1/5) of RT plans changed or remained as planned. C The patients for whom the RT plan was changed came from radical and salvage RT groups. The radical RT patients for whom the RT plan changed (n = 6), additional lymph node (LN) radiation 83.3% (5/6), and SBRT 16.6% (1/6). In the salvage RT group the RT plan change (n = 8), 62.5% (5/8) additionally received LN radiation 25% (2/8) and SBRT 37,5% (3/8), salvage RT plus boost 25% (2/8) while 12.5% (1/8) received only SBRT. D Different systemic treatments were given to patients in every group. Among the patients from the radical RT group for whom systemic therapy was added (n = 7), 57% (4/7) received ChT, 14% (1/7) received ADT, and 28.6% (2/7) received hormonal therapy (abiterone). Among the salvage RT group patients, 25% (2/8) received ChT, and the vast majority 75% (6/8) received ADT + RT. Among the oligometastatic group, 66% (2/3) received ChT, and 34% (1/3) received ADT