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Monitor testosterone during androgen-deprivation therapy: review

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – Physicians should monitor serum testosterone levels during androgen-deprivation therapy (ADT) in men with prostate cancer, according to an April 16th online report in European Urology.

Although the androgen axis is involved throughout the natural history of prostate cancer, testosterone is not routinely measured in these patients. Dr. Claude C. Schulman, from the University of Brussels, Belgium, and associates convened an expert roundtable to review evidence for measuring testosterone in prostate cancer screening, diagnosis, and treatment.

Because multiple trials show no association between prostate cancer and testosterone, they experts do not recommend testosterone measurement to assess prostate cancer risk or for screening in the general population.

There’s conflicting evidence on whether testosterone measurement improves the specificity of prostate specific antigen (PSA) tests. Until large prospective studies are conducted, the consensus panel does not advise assessment of serum testosterone-to-PSA ratio.

While several studies have linked low pretreatment serum testosterone with more aggressive tumors, recent trials have failed to confirm this link. At this time, the experts oppose using testosterone to assess tumor aggressiveness.

Current guidelines recommend PSA testing, along with digital rectal exam and symptom evaluation, to judge the efficacy of ADT. The authors say that serum testosterone is a more direct measure of treatment efficacy. Therefore, they recommend that serum testosterone be checked along with PSA levels (e.g., every three months) when first starting ADT.

If testosterone stays high and PSA is rising, the authors say treatment should be changed. “In this context, there is little evidence to guide the management decision, but options include surgical castration, change of luteinizing hormone-releasing hormone agonist, or the addition of bicalutamide,” they said.

On the other hand, low testosterone and increasing PSA may indicate a transition to castration-resistant cancer, in which case testosterone measurement is mandatory for ruling out other causes, such as poor adherence, inappropriate dosing, failure to achieve intramuscular injection or incorrect injection preparation.

Multiple trials support intermittent hormone therapy for prostate cancer as safe and feasible and a way to reduce side effects, lower health care costs and improve quality of life. Dr. Schulman and colleagues suggest testosterone measurement as a criterion for reinitiating ADT and to standardize the length of androgen re-exposure.

Finally, they recommend that mass spectrometry-based assays be used in lieu of automatic immunoassays for measuring serum testosterone in men on ADT.

Reference:

Eur Urol 2010.