Salvage radiotherapy in prostate cancer patients. Planning, treatment response and prognosis using (11)C-choline PET/CT.

OBJECTIVE - To assess the prognostic value of the therapeutic response by (11)C-choline PET/CT in prostate cancer patients with biochemical recurrence in which (11)C-choline PET/CT indicated radio-guided radiotherapy.

METHODS - The study included 37 patients initially treated with prostatectomy, who were treated due to biochemical recurrence. (11)C-choline PE/CT detected infra-diaphragmatic lymph-node involvement. All were selected for intensity modulated radiation therapy, escalating the dose according to the PET findings. One year after treatment patients underwent PSA and (11)C-choline PET/CT categorizing response (complete/partial/progression). Clinical/biochemical/image monitoring was performed until appearance of second relapse or 36 months in disease-free patients.

RESULTS - (11)C-choline PET/CT could detect lymph nodes in all 37 patients. They were 18 (48. 6%) of more than a centimetre in size and 19 (51. 3%) with no pathological CT morphology: 9 (24. 3%) with positive lymph nodes of around one centimetre and 10 (27. 0%) only less than a centimetre in size. The response by (11)C-choline PET/CT was categorised one year after radiotherapy: 16 patients (43. 2%) complete response; 15 (40. 5%) partial response, and 6 (16. 2%) progression. The response was concordant between the PSA result and (11)C-choline PET/CT in 32 patients (86. 5%), and discordant in five (13. 5%). New recurrence was detected in 12 patients (80%) with partial response, and 5 (31. 2%) with complete response. The mean time to recurrence was 9 months after partial response, and 18 months after complete response (significant difference, p<. 0001).

CONCLUSIONS - (11)C-choline PET/CT allows the selection of patients with recurrent prostate cancer candidates for radiotherapy and to plan the technique. The evaluation of therapeutic response by (11)C-choline PET/CT has prognostic significance.

Revista espanola de medicina nuclear e imagen molecular. 2016 Jan 20 [Epub ahead of print]

J R García, M Cozar, M Soler, P Bassa, E Riera, J Ferrer

Unidad PET/TC, CETIR, ERESA, Esplugues, Barcelona, España. Unidad PET/TC, CETIR, ERESA, Esplugues, Barcelona, España. , Unidad PET/TC, CETIR, ERESA, Esplugues, Barcelona, España. , Unidad PET/TC, CETIR, ERESA, Esplugues, Barcelona, España. , Unidad PET/TC, CETIR, ERESA, Esplugues, Barcelona, España. , Unidad PET/TC, CETIR, ERESA, Esplugues, Barcelona, España.

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