Diagnostic performance of bone scintigraphy and 11C-choline PET/CT in the detection of bone metastases in patients with biochemical recurrence of prostate cancer

Abstract

Aim

To compare bone scan (BS) with ¹¹C-choline PET/CT for the detection of bone metastases in patients with biochemical recurrence of prostate cancer (PC).

Materials and methods

A total of 169 patients with biochemical recurrence of PC (PSA: 2.4–58 ng/ml) who were referred for both exams (0–15 days-in-between) were included. Lesion-detection-rate per patients and lesions were analyzed for both BS and ¹¹C-choline PET/CT. Metastases were diagnosed by: biopsy, CT/¹⁸F-fluoride PET/MRI confirmation, or evidence of progression in subsequent imaging procedures.

Results

A total of 91 lesions were found to be active in BS and/or ¹¹C-choline PET/CT (40 patients), with 78 of which were metastatic.

BS detected 38 blastic, 2 lytic and 10 non-CT-evident lesions. ¹¹C-choline PET/CT detected 41 blastic, 4 lytic and 29 non-CT-evident lesions. BS and ¹¹C-choline PET/CT sensitivities were 65.4% and 96.1%; specificities are 38.5 and 92.3% (χ² 8.27, p < 0.04).

Both imaging techniques were negative in 118 patients. Tracer avid lesions were found in 51 patients: with 30/51 being BS and ¹¹C-choline PET/CT concordant; in 21/51 patients had discordant lesions (kappa 0.712, p = 0.00).

Lesions were absolutely discordant in 10/19 patients: 5 FN BS, 2 FP BS (degenerative changes; dysplasia), 1 FN ¹¹C-choline PET/CT (blastic), 1 FP ¹¹C-choline PET/CT (degenerative), 1 out of field-of-view lesion with ¹¹C-choline PET/CT (tibia alone).

¹¹C-choline PET/CT showed extraosseous involvement in 26/51 patients with bone metastases: 9 local recurrences, 5 infra-diaphragmatic-lymph-nodes, 2 supra-diaphragmatic, 5 local and infra-diaphragmatic, 4 infra- and supra-diaphragmatic, 1 supra-diaphragmatic and lung metastases.

Conclusion

¹¹C-choline PET/CT yielded better sensitivity and specificity than BS for the detection of bone involvement in patients with biochemical recurrence of PC and allowed extraosseous restaging, with an impact in the clinical management of these patients.

Resumen

Objetivo

Comparamos la gammagrafía ósea (GO) y la ¹¹C-colina-PET/TAC en la detección de metástasis óseas en pacientes con recidiva bioquímica de cáncer de próstata (CaP).

Material y métodos

Ciento sesenta y nueve pacientes que acudieron para realizar ambas exploraciones (0–15 días) por recidiva bioquímica (PSA: 2,4–58 ng/ml) de CaP. Analizamos la tasa de detección de GO y ¹¹C-colina-PET/TAC por pacientes y lesiones. El diagnóstico de metástasis se realizó por: biopsia, confirmación TAC/¹⁸F-fluoruro PET/RM, progresión por técnicas de imagen.

Resultados

Noventa y una lesiones captantes mediante GO y/o ¹¹C-colina-PET/TAC (40 pacientes), 78 de ellas metastásicas.

GO detectó 38 blásticas, 2 líticas y 10 sin traducción-TAC. ¹¹C-colina-PET/TAC: 41 blásticas, 4 líticas y 29 sin traducción-TAC. La sensibilidad de GO y ¹¹C-colina-PET/TAC fue del 65,4 y 96,1%; la especificidad del 38,5 y 92,3% (χ² 8,27, p < 0,04).

En 118 pacientes ambas exploraciones fueron negativas. En 51 pacientes mostraron lesiones captantes: 30/51 GO y ¹¹C-colina-PET/TAC concordantes. En 21/51 mostraron lesiones discordantes (kappa 0,712, p = 0,00).

En 10/19 pacientes la discordancia fue total: 5 FN GO, 2 FP GO (degenerativa; displasia), uno FN ¹¹C-colina-PET/TAC (blástica), uno FP ¹¹C-colina-PET/TAC (degenerativa), uno fuera campo ¹¹C-colina-PET/TAC (tibial única).

¹¹C-colina PET/TAC detectó enfermedad extraósea en 26/51 pacientes con metástasis óseas: 9 local, 5 adenopatías infradiafragmáticas, 2 supradiafragmáticas, 5 local e infradiafragmática, 4 infra y supradiafragmáticas, una supradiafragmáticas y metástasis pulmonares.

Conclusión

La ¹¹C-colina-PET/TAC muestra una mayor sensibilidad y especificidad que la GO en la detección de metástasis óseas en pacientes con recidiva bioquímica de CaP. Además, permite la reestadificación extraósea, con impacto en el manejo de estos pacientes.