Metastatic Prostate Cancer Proven by 18F-FCH PET/CT Staging Scan in Patient With Normal PSA but High PSA Doubling Time

Molecular predictors of metastasis in patients with prostate cancer

INTRODUCTION

Prostate cancer is a serious threat to the health of older adults worldwide. The quality of life and survival time of patients sharply decline once metastasis occurs. Thus, early screening for prostate cancer is very advanced in developed countries. The detection methods used include Prostate-specific antigen (PSA) detection and digital rectal examination. However, the lack of universal access to early screening in some developing countries has resulted in an increased number of patients presenting with metastatic prostate cancer. In addition, the treatment methods for metastatic and localized prostate cancer are considerably different. In many patients, early-stage prostate cancer cells often metastasize due to delayed observation, negative PSA results, and delay in treatment time. Therefore, the identification of patients who are prone to metastasis is important for future clinical studies.

AREAS COVERED

this review introduced a large number of predictive molecules related to prostate cancer metastasis. These molecules involve the mutation and regulation of tumor cell genes, changes in the tumor microenvironment, and the liquid biopsy.

EXPERT OPINION

In next decade, PSMA PET/CT and liquid biopsy will be the excellent predicting tools, while ¹⁷⁷ Lu- PSMA-RLT will be showed excellent anti-tumor efficacy in mPCa patients.

Imaging of Prostate Cancer Using 18F-Choline PET/Computed Tomography

¹⁸F-fluorocholine (FCH) PET/computed tomography (CT) is a valuable imaging modality in prostate cancer disease. Probably, its main role is restaging of patients with biochemical recurrence after radical prostatectomy or external beam radiotherapy. ¹⁸F-FCH PET/CT is strengthening its position in the initial staging, biopsy target definition, radiotherapy planning, and therapy monitoring. Gleason score and prostate-specific antigen value, doubling time, and velocity can influence positivity of ¹⁸F-FCH PET/CT. The influence of androgen deprivation therapy on choline uptake is not precisely clarified. Collaboration between nuclear medicine physicians, radiologists, urologists, oncologists, and radiotherapists is crucial to help patients with prostate cancer disease.

The ability of 18F-choline PET/CT to identify local recurrence of prostate cancer

PURPOSE

To determine when 18F-choline PET/CT can truly identify local recurrence of prostate cancer.

METHODS

1031 patients from 3 European centers underwent (18)F-choline PET/CT (FCH PET/CT) for recurrent disease; 131 subjects (12.7%) showed a positive FCH uptake in the prostatic gland or prostatic fossa. Median age was 72 years (range 48-87 years), and the median PSA level at the time of FCH PET/CT scan was 4.41 ng/mL (0.22-18.13 ng/mL). 45 patients (34.4%) had a Gleason score (GS) >7, and the residual subjects had a GS ≤ 7. The assessment of true or false-positive FCH PET/CT findings was made by magnetic resonance imaging (n = 34) and/or biopsy in 75/131 cases. A χ (2) test and a Z Kolmogorov-Smirnov test were used to assess the correlation between clinical variables (age, PSA, GS, type of therapy) and FCH PET/CT findings.

RESULTS

FCH PET/CT resulted truly positive (TP) for recurrent disease in the prostatic gland/fossa in 59/75 patients (79%) and falsely positive (FP) in 16 subjects (21%). The median value of PSA at the time of FCH PET/CT scan was higher in TP as compared to FP, although not statistically significant (4.76 vs. 3.04 ng/mL p > 0.05). Similarly, median age, GS categories, and the type of therapy were similar between the two groups (p > 0.05). However, when matching GS categories and PSA values, we found that the number of patients with TP findings were higher in the case of a PSA > 2 ng/mL, independently from the GS (ranging between 74% and 92%). Conversely, FP rate ranged between 50% and 65% in patients with a PSA ≤ 2 ng/mL, especially in the case of GS ≤ 7, whereas FP was around 25% in those with a GS >7 and PSA > 2 ng/mL.

CONCLUSIONS

FCH PET/CT has a limited role in evaluation of prostatic gland/fossa recurrence, due to the physiological biodistribution of the radiopharmaceutical agent. However, in 70-90% of patients with a PSA >2 ng/mL, independently from GS, a focal FCH uptake is compatible with a true local recurrence.

Gleason score at diagnosis predicts the rate of detection of 18F-choline PET/CT performed when biochemical evidence indicates recurrence of prostate cancer: experience with 1,000 patients

The objective of this study was to explore the ability of the initial Gleason score (GS) to predict the rate of detection of recurrent prostate cancer (PCa) with (18)F-choline PET/CT in a large cohort of patients.

METHODS

Data from 1,000 patients who had undergone (18)F-choline PET/CT because of biochemical evidence of relapse of PCa between 2004 and 2013 were retrieved from databases at 4 centers. Continuous data were compared by the Student t test or ANOVA, and categoric variables were compared by the χ(2) test. Univariable and multivariable analyses were performed by logistic regression.

RESULTS

The GS at diagnosis was less than or equal to 6 in 257 patients, 7 in 347 patients, and greater than 7 in 396 patients. The results of 645 PET/CT scans were positive for PCa recurrence. Eighty-one percent of the positive PET/CT results were found in patients with a PSA level of greater than or equal to 2 ng/mL, 43% were found in patients with a PSA level of 1-2 ng/mL, and 31% were found in patients with a PSA level of less than or equal to 1 ng/mL; 78.8% of patients with positive PET/CT results had a GS of greater than 7. The results of (18)F-choline PET/CT scans were negative in 300 patients; 44% had a GS of less than or equal to 6, 35% had a GS of 7, and 17% had a GS of greater than 7. PET/CT results were rated as doubtful in only 5.5% of patients (median PSA, 1.8 ng/mL). When the GS was greater than 7, the rates of detection of (18)F-choline PET/CT were 51%, 65%, and 91% for a PSA level of less than 1 ng/mL, 1-2 ng/mL, and greater than 2 ng/mL, respectively. In univariable and multivariable analyses, both a GS of 7 and a GS of greater than 7 were independent predictors for positive (18)F-choline PET/CT results (odds ratios, 0.226 and 0.330, respectively; P values for both, <0.001).

CONCLUSION

A high GS at diagnosis is a strong predictive factor for positive (18)F-choline PET/CT scan results for recurrent PCa, even when the PSA level is low (i.e., ≤1 ng/mL).

Consequence of the introduction of routine FCH PET/CT imaging for patients with prostate cancer: a dual centre survey

Background

Fluorocholine(18F) (FCH) was introduced at the beginning of April 2010 in France, Slovenia and three other EU member states for the localisation of bone metastases of prostate cancer with PET. The aim of the study was to compare the evolution of diagnostic imaging in patients with prostate cancer using a new radiopharmaceutical FCH, observed in France and in Slovenia, and to quantify the consequence of the results of new imaging modality on the detection rate of abnormal metastases and recurrences of prostate cancer.

Patients and methods

In two centres (France/Slovenia), a survey of the number of nuclear medicine examinations in patients with prostate cancer was performed, covering 5 quarters of the year since the introduction of FCH. For each examination, the clinical and biological circumstances were recorded, as well as the detection of bone or soft tissue foci.

Results

Six hundred and eighty-eight nuclear medicine examinations were performed impatients with prostate cancer. Nuclear medicine examinations were performed for therapy monitoring and follow-up in 23% of cases. The number of FCH PET/CT grew rapidly between the 1^st and 5^th period of the observation (+220%), while the number of bone scintigraphies (BS) and fluoride(18F) PET/CTs decreased (−42% and −23% respectively). Fluorodeoxyglucose(18F) (FDG) PET/CT remained limited to few cases of castrate-resistant or metastatic prostate cancer in Paris. The proportion of negative results was significantly lower with FCH PET/CT (14%) than with BS (49%) or fluoride(18F) PET/CT (54%). For bone metastases, the detection rate was similar, but FCH PET/CT was performed on average at lower prostate-specific antigen (PSA) levels and was less frequently doubtful (4% vs. 28% for BS). FCH PET/CT also showed foci in prostatic bed (53% of cases) or in soft tissue (35% of cases).

Conclusions

A rapid development of FCH PET/CT was observed in both centres and led to a higher detection rate of prostate cancer lesions.