Study: Selen and prostate cancer: Develop the network of contradictory data

Reference

Stratton MS, Algotar on, Ranger-Moore J, et al. Oral selenium supplement has no influence on the speed of the prostate -specific antigen in men who are actively monitored on localized prostate cancer. cancer previous res . 2010; 3: 1035-1043.

Design

randomized, double -blind intervention study

participant

140 men with localized prostate cancer (approx.), who had decided to postpone allopathic treatment and to which "watchful wait"

study medication and dosage

Selen (SE) 200 µg/day or 800 µg/day as selenied yeast or placebo, followed over a period of up to 5 years

primary result dimensions

The prostate -specific antigen (PSA) changes over time as an estimate of the progress of the CA

most important knowledge

The increase in PSA values ​​over time was similar in all groups. In men with the highest SE status at the beginning of the course, those who were assigned the higher SE dose (800 µg) showed a faster increase in PSA values ​​compared to those who received placebo or a lower SE dose.

effects on practice

Years ago, a group of researchers, under the direction of the late Larry Clark, reported in a randomized, blinded study that SE supplementation was essentially halved, an effect that was statistically significant. appears.

The Clark study followed that a diet with a high SE content (measured by the Zeh-SE) is associated with a 65 % reduced risk for the development of an advanced prostate-CA. ^{2 other reports confirmed that a higher SE status is associated with a lower risk. Do not confirm context.}

Follow-ups from Clarks Group continued to find protective effects, but only for men with plasma-SE values ​​<106 ng/ml in a report. ^{7 or <132 ng/ml and with exit PSA values ​​under 4 in another. 8 Other reports indicate that the greatest protection among smokers Appearance. 9.10}

It should be noted that there is no clinical evidence that additional SE has an effect pharmacologically effect. If additional SE actually protects against prostate-CA, this rather seems to be done simply by overcoming a defect.

Recently, indications were found that genetic variations (including the synthesis of manganese superoxide dismutase) influence the relationship between SE status and the prostate-CA risk. In some subgroups, a higher plasma-SE value was associated with A higher Risk for aggressive diseases, while in other subgroups a higher plasma-SE value was associated with A lower risk. It can be premature to include these latest knowledge in the decision -making process of a doctor until the evidence is confirmed independently.

At the beginning of 2009, a large randomized study came to the conclusion that additional SE is useless when previously prevents prostate-ca. Selenized yeast was used in the successful attempt. Preliminary examinations indicate that seleniated yeast may have advantages in combating cancer in other forms of this micronutrient lack.

What should we think of the results of the new study? It came empty, but its results don't tell us about primary prevention. Remember that primary prevention was the focus of the original successful attempt. In other words, additional SE in the form of selenised yeast could help to ever get men (if only men with a defect) who were never ill from prostate CA, ever to develop it. At the same time, it may not help those in whom a diagnosis has already been made.

Apart from the question of primary versus secondary prevention, we might have predicted a failure in advance when looking through the small print of the new study. The SE status among the subjects of the new report was much better than in the successful study by Larry Clark et al.

The difference between the bad SE status among the subjects of the Clark study and the better SE status at the subjects in the new report was statistically highly significant ( p <0.0001).

The difference between the bad SE status among the subjects of the Clark study and the better SE status at the subjects in the new report was statistically highly significant ( p <0.0001). Earlier findings had already shown that higher SE status probably excludes expected benefits. Therefore, we would have expected the new report to show no benefit.

The negative results of the new report only underline the fact that the protective effect of SE is limited to the remedy of deficits. The authors of the new study admit: "Combination of the results of our study with those of NPC." [The Clark Trial] suggests that a selenium supplement based on the plasma relocation center could have a different effect on the incidence or the progression of prostate cancer. ” They continue to state: "The limitation of the selenium output concentrations to determine the suitability could enable future studies to only concentrate on the subjects who are most likely to benefit."

until we know more, I think it makes sense to add 200 µg SE (but no longer) in the form of selenium yeast for prevention purposes only in men with low SE levels in the plasma (perhaps <106 ng/ml) and to consider PSA values ​​<4. We now know that higher doses can even be dangerous, at least for some of the men. We still have no reason to use additional SE to prevent prostate-CA in men with sufficient plasma-SE mirrors.

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