Accumulation of [ 11 C]acetate in normal prostate and benign prostatic hyperplasia: comparison with prostate cancer

Abstract

Carbon-11 acetate positron emission tomography (PET) has been reported to be of clinical value for the diagnosis of prostate cancer. However, no detailed analysis has yet been carried out on the physiological accumulation of [(11)C]acetate in the prostate. The purpose of this study was to elucidate the physiological accumulation of [(11)C]acetate in the prostate using dynamic PET. The study included 30 subjects without prostate cancer [21 with normal prostate and nine with benign prostatic hyperplasia (BPH)] and six patients with prostate cancer. A dynamic PET study was performed for 20 min after intravenous administration of 555 MBq of [(11)C]acetate. The standardised uptake value (SUV) at 16-20 min post tracer administration and the early-to-late-activity ratio of the SUV (E/L ratio), which was determined by dividing the SUV(6-10 min) by the SUV(16-20min), were calculated to evaluate the accumulation of [(11)C]acetate. The prostate was clearly visualised and distinguished from adjacent organs in PET images in most of the cases. The SUV of the prostate (2.6+/-0.8) was significantly higher than that of the rectum (1.7+/-0.4) or bone marrow (1.3+/-0.3) ( P<0.0001 in each case). The SUV of the normal prostate of subjects aged <50 years (3.4+/-0.7) was significantly higher than both the SUV for the normal prostate of subjects aged > or =50 years (2.3+/-0.7) and that of subjects with BPH (2.1+/-0.6) ( P<0.01 in each case). The primary prostate cancer in six cases was visualised by [(11)C]acetate PET. However, the difference in the SUV between subjects aged > or =50 with normal prostate or with BPH and the patients with prostate cancer (1.9+/-0.6) was not statistically significant. There was also no significant difference in the E/L ratio between subjects aged > or =50 with normal prostate (0.98+/-0.04) or BPH (0.96+/-0.08) and patients with prostate cancer (1.02+/-0.12). In conclusion, a normal prostate exhibits age-related physiological accumulation of [(11)C]acetate. Careful interpretation of [(11)C]acetate PET images of prostate cancer is necessary because the SUV and the E/L ratio for the normal prostate and for BPH overlap significantly with those for prostate cancer.

1-11C-Acetate Kinetics of Prostate Cancer

“…As reported by Kato et al (8), the early uptake is the same as the late uptake, and the early-to-late uptake ratio is not significantly different from unity for any of the patients. The suggestion that the ratio is higher for primary prostate cancer and could be used for differentiation (4) is not supported by our data or those from Kato et al (8). In this respect, prostate cancer behaves similarly to the behavior of normal prostate tissue.…”

“…The radiopharmaceutical 1-11 C-acetate appears superior to 18 F-FDG in staging primary and recurrent prostate cancer (5-7). However, benign prostate hyperplasia (BPH) has similar uptake as malignant neoplasia (4,8), just as 18 F-FDG (9). Some of the discrepancies reported in the literature could be attributed to the acquisition protocol, static versus dynamic, and the timing of the images.…”

“…Some of the discrepancies reported in the literature could be attributed to the acquisition protocol, static versus dynamic, and the timing of the images. Kato et al (8) performed a dynamic acquisition in men with a normal prostate gland and found an age dependence of the acetate uptake. In addition, they found a similar acetate uptake in BPH and prostate cancer.…”

Long-Term Post-Treatment MR and PET/CT Imaging in Prostate Cancer Patients in Complete Remission after Curative Radiotherapy with or without Androgen Deprivation: The Image of Cure

“…Kato et al showed that in comparison with normal or hyperplasic prostate tissue, primary prostate cancer has a higher early-to-late SUV activity ratio for AC [26]. The impact of early and late runs in recurrent prostate cancer has been pointed out in another study of our group [27].…”

Radiotracers Used in Nuclear Medicine for Prostate Cancer Diagnosis and Follow-Up

“…The 11C-acetate is unable to distinguish between benign prostatic hyperplasia (BPH) and prostate cancer. Data available to date report that sensitivity and specificity with regard to detection and evaluation of lymph node involvement are quite heterogeneous, since the results of studies with larger numbers of patients range from 73-88% for sensitivity and 29-41% for specificity in the detection of the primary tumor, whereas for lymph node staging, sensitivity ranges from 38-90% and specificity ranges from 67-96%, since the higher the PSA level is, the higher the specificity will be 42,43 . The greatest usefulness of this agent is in disease localization in case of biochemical recurrence, where the detection rate will also be highly influenced by PSA levels: using a PSA duplication velocity > 1.32 ng/ml it will have 74% sensitivity and 75% specificity, whereas an accuracy of up to 59% will be obtained in patients with PSA levels > 3 ng/ml, and it will be as low as 4% if PSA levels are lower (Fig.…”