PET/CT com Fluorocolina‐F18 no estadiamento inicial do carcinoma da próstata

Aim

In the evaluation of prostate cancer, clinical nomograms are commonly used to predict the probability of lymphatic and extra‐nodal spread. Those nomograms may suggest the presence and the extension of this cancer but do not allow a clear distinction between loco‐regional and distant disease. In this study, it was intended to evaluate the usefulness of 18F‐Fluorocoline positron emission tomography/computed tomography (18F‐FCH‐PET/CT) in the workup of patients with the initial diagnosis of prostate cancer and staged by this imaging technique.

Material and methods

The medical records of 39 patients with prostate cancer who underwent 18F‐FCH PET/CT for initial staging, between November 2010 and April 2015, were reviewed. Of these, 20 patients were excluded because they had already started hormonotherapy. In the other 19 patients, the performance of 18F‐FCH PET/CT for the detection of lymph node metastasis was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy. Six patients had performed pelvic lymphadenectomy (total of 69 lymph nodes), allowing histological confirmation. When there was no histological confirmation (total of 30 lymph nodes and 3 cases of bone metastasis), the findings of 18F‐FCH PET/CT were correlated with the values of PSA and the information from multiple imaging modalities such as CT, bone scan, magnetic resonance (MRI), 18F‐Sodium Fluoride (18F‐NaF) PET/CT of control.

Results

The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for lymph node metastasis detection were, respectively, 96.8%, 80.9%, 69.8%, 98.2% and 85.8%. In our sample, this technique also allowed the identification of nodal extra pelvic or bone metastasis in 5 patients (26.3%) with implications in the treatment. It showed uptake suggestive of bone metastasis, corroborated by other diagnostic technics or by the follow‐up, in 3 patients, those with prostate specific antigen (PSA) of 9.5 ± 2.9 ng/mL.

Conclusion

18F‐FCH PET/CT is an entire body and multi organ imaging modality that allows the identification, globally, of the sites of disease in patients with prostate cancer. In this study, 18F‐FCH PET/CT showed good results when used in the initial staging of these patients. It is highlighted the ability to detect distant disease, in particular bone metastasis, even with PSA< 20 ng/mL.