The role of positron emission tomography/computed tomography imaging with radiolabeled choline analogues in prostate cancer

Usefulness of 18F-Choline Positron Emission Tomography - Computed Tomography in the therapeutic management of patients with biochemical recurrence of prostate adenocarcinoma treated with brachytherapy

OBJECTIVE

The objective of the study was to evaluate the usefulness of 18F-choline PET/CT in biochemically recurrent prostate cancer patients treated with brachytherapy, as well as to assess the changes in therapeutic management derived from its outcome.

MATERIAL AND METHODS

Retrospective study of 20 patients between 51 and 78 years old, with a history of prostate adenocarcinoma that had been treated with brachytherapy and presented biochemical recurrence (PSA 3.1-12 ng/ml) and staging tests (CT and bone scan) without alterations, were included. The findings visualized in the PET/CT scan with ¹⁸F-choline were correlated with the histopathology and/or the evolution of the PSA after therapy.

RESULTS

¹⁸F-choline PET/CT scan only detected local recurrence in 15 patients. Local and regional recurrences were seen in 4 patients, and 1 patient presented local and bone recurrence. Local recurrence detected in PET was confirmed by anatomopathological studies in 85% of the cases. In one patient, these findings (PET scan) turned out to be prostatitis, and it could not be confirmed in another patient. Of the cases with local and regional recurrence, local recurrence was histologically confirmed in 3 out of 4 patients. ¹⁸F-choline PET/CT changed the therapeutic management in 25% of the patients, discarding the initially planned salvage surgery in 3 cases, 1 radiotherapy and 1 brachytherapy.

CONCLUSION

¹⁸F-choline PET/CT could be a useful technique in the group of patients with biochemical recurrence after brachytherapy, providing locoregional and distant involvement findings which had not been detected with conventional imaging tests, thus determining a more adequate therapeutic management.

Role of PET-CT with 18F-fluorocholine in biochemical recurrence after treatment of prostate cancer with curative intent

OBJECTIVES

To analyse the ability of the PET-CT with ¹⁸F-fluorocholine (¹⁸F-FCH) to detect disease on biochemical recurrence after treatment with curative intent. To determine the clinical variables that would be able to optimise the test's diagnostic yield.

MATERIAL AND METHODS

A retrospective study of PET-CTs with ¹⁸F-fluorocholine performed on 61 patients with prostate cancer who had undergone treatment with curative intent and met the criteria for biochemical recurrence. The results of the PET-CT were categorised into positive or negative and were validated using pre-established criteria. The relationship between the result of the PET-CT and the initial PSA nadir, PSA trigger, rising PSA velocity (PSAva) and PSA doubling time (PSAdt). The relationship between the metastatic sites on the PET-CT and the remaining variables was analysed.

RESULTS

There was a 34.4% detection rate of the disease. The initial PSA, PSA nadir, PSA trigger and PSAva showed statistically significant differences according to the result of the PET-CT. The best discriminatory cut-off point between a positive or negative PET-CT for PSA trigger and PSAva was 3.5ng/ml and 0.25ng/ml/month respectively. The PSAdt was significantly lower in patients with remote disease compared to patients with localised disease (5.1 vs 16.8 months, P=.01). The probability that the PET-CT would detect remote disease vs localised disease was 3.2 times higher if the PSAdt was under 6 months (80% vs 20%, OR: 3.2, P=.02). In the multivariate analysis, only the initial PSA and not having undergone radical prostatectomy were demonstrated as independent predictive factors of a positive PET-CT result.

CONCLUSIONS

The PET-CT with ¹⁸F-FCH can detect disease in a high percentage of patients with biochemical recurrence and provides information on its anatomical location. PSA kinetics and the patient's previous treatment are key variables in increasing the test's diagnostic.