Stopping progression is crucial. According to Scardino, for those whose disease does progress, the risk of death is much higher -- nearly 50 percent.
"I think it's an important study," Scardino said. That lycopene and bulk carotenoids reduced the risk of progressing to advanced disease without impacting the risk of developing prostate cancer overall, he said, "suggests maybe these micronutrients are not as important in [stopping] carcinogenesis as they are in [slowing] progression of a very small early tumor to one that becomes invasive and larger and develops the ability to metastasize."
"The study provides supportive evidence that lycopene and the carotenoids may have an effect on delaying the progression of prostate cancer, so, from that point of view, it is an interesting study," Scardino added.
But Alan Kristal, associate head of the Cancer Prevention Program at the Fred Hutchinson Cancer Research Center in Seattle, remained more skeptical. Though he called the study "well-executed," Kristal noted, for instance, that the authors were unable to control for prostate-specific antigen (PSA) testing among the men. These blood tests often detect clinically irrelevant tumors, he explained.
"You can never do an observational study of prostate cancer without rigorously controlling for whether or not the person got PSA screening," Kristal said. "The more times you take the test, the more likely you are to get the disease."
He also noted that the finding for lycopene contradicts a
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