Eleven is the magic number. Eleven pounds of lost weight can reduce the risk of an advanced form of prostate cancer, according to researchers from the American Cancer Society and the Duke University Prostate Center.
Researchers, who tracked the weight of 70,000 men between 1982 and 1992 and then followed them until 2003, found men who lost more than 11 pounds had a lower risk of developing prostate cancer than men whose weight remained the same.
Studies have long shown obese men are at greater risk for prostate cancer. But this study, published in this month's Cancer Epidemiology, Biomarkers & Prevention, is the first to indicate that recent weight loss can decrease risk by roughly 40 percent.
1. Thanks, Jacki, for posting this most interesting study. Your tip motivated me to read the full story and check the abstract itself in PubMed. I have a hunch this is one of those studies that is going to affect the thinking of many researchers, physicians and patients.
The bottom line finding, quoting from the abstract: "Obesity increases the risk of more aggressive prostate cancer and may decrease either the occurrence or the likelihood of diagnosis of less-aggressive tumors. Men who lose weight may reduce their risk of prostate cancer."
I found this particularly useful because the relationship of obesity and prostate cancer had been confusing to me, and because the study was based on a very large group (69,991 men in the Cancer Prevention Study II Nutrition Cohort) followed for a long time (1982 through June 30, 2003) among whom 5,252 prostate cancers had been found (excluding the first two years of follow-up, no doubt to minimize the number of men who already had cancer at the start).
I was confused because Dr. Myers, Dr. Moyad and other leading communicators about nutrition, diet, supplements, lifestyle and prostate cancer stress the connection of obesity and prostate cancer, yet, when I surveyed studies for myself in PubMed, sometimes obesity seemed to actually cut the risk. The researchers appear to have found the answer: obesity cut either the ability to detect and/or the risk of low-grade prostate cancer a bit (best estimate is an 84% risk compared to non-obese or overall total group risk, I'm not sure which), but increases the risk of nonmetastatic high-grade prostate cancer by 22% (with the high confidence range that the true percent increase is between 96% and 155%). That confidence range convinces me that there is a substantial increase in risk.
The major finding was that men who had lost more than 11 pounds between 1982 and 1992 were at a decreased risk of nonmetastatic high-grade prostate cancer, which was the point you highlighted in your blog.
The researchers based their obesity indicator on Body Mass Index, which has some flaws. For instance, people with a lot of muscle score higher than they should, judging by true obesity, on the BMI scale. However, BMI seems to me to be valid enough to support the findings of this study.
I wondered why they were not mentioning men diagnosed with metastatic disease. I suspect the answer is that this group was monitored often enough that metastatic disease did not have time to develop or was excluded when they dropped those diagnosed with prostate cancer in the first two years of follow-up, a tactic that is useful in order to minimize those who already had cancer at the start, as mentioned above.
I have kept my body weight and fat under fairly good control, but this news and clarification of the relationship of body fat and aggressive cancer motivates me to make a special effort to lose some pounds.
Thanks again,
Jim (web site: http://www.mycancerplace.com/profile.php?id=147 )
Posted at 9:17PM on Dec 28th 2006 by Jim Waldenfels