Prostate imaging modalities that can be used for complementary and alternative medicine clinical studies

Prostate-specific antigen and prostate-specific antigen velocity as threshold indicators in 11C-acetate PET/CTAC scanning for prostate cancer recurrence

PURPOSE

The aim of this study was to identify which patient characteristics are associated with the highest likelihood of positive findings on 11C-acetate PET/computed tomography attenuation correction (CTAC) (PET/CTAC) scan when imaging for recurrent prostate cancer.

METHODS

From 2007 to 2011, 250 11C-acetate PET/CTAC scans were performed at a single institution on patients with prostate cancer recurrence after surgery, brachytherapy, or external beam radiation. Of these patients, 120 met our inclusion criteria. Logistic regression analysis was used to examine the relationship between predictability of positive findings and patients' characteristics, such as prostate-specific antigen (PSA) level at the time of scan, PSA kinetics, Gleason score, staging, and type of treatment before scan.

RESULTS

In total, 68.3% of the 120 11C-acetate PET/CTAC scans were positive. The percentage of positive scans and PSA at the time of scanning and PSA velocity (PSAV) had positive correlations. The putative sensitivity and specificity were 86.6% and 65.8%, respectively, when a PSA level greater than 1.24 ng/mL was used as the threshold for scanning. The putative sensitivity and specificity were 74% and 75%, respectively, when a PSAV level greater than 1.32 ng/mL/y was used as the threshold. No significant associations were found between scan positivity and age, PSA doubling time, Gleason score, staging, or type of treatment before scanning.

CONCLUSIONS

This retrospective study suggests that threshold models of PSA greater than 1.24 ng/mL or PSAV greater than 1.32 ng/mL per year are independent predictors of positive findings in 11C-acetate PET/CTAC imaging of recurrent prostate cancer.

Ascorbate as a co-factor for fe- and 2-oxoglutarate dependent dioxygenases: physiological activity in tumor growth and progression

Ascorbate is a specific co-factor for a large family of enzymes known as the Fe- and 2-oxoglutarate-dependent dioxygenases. These enzymes are found throughout biology and catalyze the addition of a hydroxyl group to various substrates. The proline hydroxylase that is involved in collagen maturation is well known, but in recent times many new enzymes and functions have been uncovered, including those involved in epigenetic control and hypoxia-inducible factor (HIF) regulation. These discoveries have provided crucial mechanistic insights into how ascorbate may affect tumor biology. In particular, there is growing evidence that HIF-1-dependent tumor progression may be inhibited by increasing tumor ascorbate levels. However, rigorous clinical intervention studies are lacking. This review will explore the physiological role of ascorbate as an enzyme co-factor and how this mechanism relates to cancer biology and treatment. The use of ascorbate in cancer should be informed by clinical studies based on such mechanistic hypotheses.

A convenient method for measuring blood ascorbate concentrations in patients receiving high-dose intravenous ascorbate

OBJECTIVE

A simple method of using fingerstick blood glucose (FSBG) monitors to estimate blood ascorbate values after high-dose intravenous (IV) ascorbate infusion is evaluated as a substitution for high-performance liquid chromatography (HPLC) measurement.

METHODS

In 33 participants, readings from FSBG monitors were taken before and after IV ascorbate infusions at various time points, with the postinfusion FSBG readings subtracted from the baseline glucose readings. The results of the subtractions (AAFSBG) were correlated with ascorbate concentrations detected by HPLC (AAHPLC).

RESULTS

A linear regression was found between ascorbate concentrations detected by the fingerstick method (AAFSBG) and by HPLC (AAHPLC). The linear correlations were identical in healthy subjects, diabetic subjects, and cancer patients. Analysis of variance obtained an AAFSBG/AAHPLC ratio of 0.90, with a 90% confidence interval of (0.69, 1.20). The corrections of AAFSBG improved similarity to AAHPLC but did not significantly differ from the uncorrected values.

CONCLUSION

The FSBG method can be used as an approximate estimation of high blood ascorbate concentration after IV ascorbate (>50 mg/dL, or 2.8 mM) without correction. However, this measurement is not accurate in detecting lower or baseline blood ascorbate. It is also important to highlight that in regard to glucose monitoring, FSBG readings will be erroneously elevated following IV ascorbate use and insulin should not be administered to patients based on these readings.