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Guide to News from Johns Hopkins at AACR Meeting - 04/16/2010

Guide to News from Johns Hopkins at AACR Meeting

Release Date: April 16, 2010

These news tips are based on abstracts and presentations by Johns Hopkins Kimmel Cancer Center scientists scheduled to present their work at the 101st annual meeting of the American Association for Cancer Research (AACR), April 17-21, in Washington, D.C.  Please refer to the embargo times listed below for each item.

Follow all day tweets from the meeting at www.twitter.com/hopkinsmednews

OBESITY AND WEIGHT GAIN NEAR TIME OF PROSTATE CANCER SURGERY DOUBLES RISK OF RECURRENCE
Abstract # 883

*Editors Note: a press conference regarding this research will be held at the AACR meeting in the Walter E. Washington Convention Center on Tuesday, April 20 at 8:30 a.m. ET.  To call in to the press conference, dial (888) 282-7404, conference code: 59334057.

Johns Hopkins epidemiologists say that prostate cancer patients who gain five or more pounds near the time of their prostate surgery are twice as likely to have a recurrence of their cancer compared with patients whose weight is stable.

“We surveyed men whose cancer was confined to the prostate, and surgery should have cured most of them, yet some cancers recurred.  Obesity and weight gain may be factors that tip the scale to recurrence,” says Corinne Joshu, Ph.D., M.P.H., postdoctoral fellow at the Johns Hopkins Bloomberg School of Public Health.

Joshu and her colleagues sent questionnaires to 1,337 men with prostate cancer who had undergone surgery to remove their prostate at the Johns Hopkins Hospital. The researchers asked each participant to recall their dietary, lifestyle and medical factors from five years before their surgery through one year after.

Results show that men whose weight increased more than 2.2 kg (or about five pounds of total weight) during the time period had twice the rate of recurrence compared with men whose weight remained the same.  On average, the study participants who gained weight reported that they gained about 10 pounds in the five years before surgery and one year postoperation.

“The good news is that being physically active reduced the risk of recurrence associated with obesity,” says Elizabeth Platz, Sc.D., M.P.H., associate professor at the Johns Hopkins Bloomberg School of Public Health and co-director of cancer prevention and control at the Johns Hopkins Kimmel Cancer Center.

Platz says that there are a variety of biochemical pathways that may be active in the body depending on daily activity.  These pathways also may vary in their impact depending on the stage and type of prostate cancer and timing of obesity and weight gain.

According to the researchers, study size was too small to determine whether weight loss can reverse the recurrence risk.  They warn that current prostate cancer patients should heed their physician’s advice on weight loss and activity near the time of surgery.

“The overriding message is one that has been repeated many times: adult men should avoid obesity and weight gain,” says Platz.  “Plus, it will likely have an impact on many aspects of their health.”

Joshu and Platz say that several confounding factors may have had an impact in the results, including patients’ ability to accurately recall their weight and lifestyle around the time of their surgery.  Also, PSA values, an indicator of recurrence, tend to be lower in obese men, so physicians may be slower to detect their recurrent disease.  “So, our study may be underestimating the risk of recurrent disease in these men,” says Joshu.

Funding for the study was provided by the National Cancer Institute.

Additional research participants include Alison Mondul from the National Cancer Institute; Misop Han, Elizabeth Humphreys, and Patrick Walsh from Johns Hopkins; and Stephen Freedland from Duke University.

BIOMARKERS ACCURATELY PREDICT WHICH MEN MAY NEED TREATMENT FOR PROSTATE CANCER
Abstract # 2731

A blood test for certain forms of prostate specific antigen (PSA) and measurement of DNA content in biopsy tissue accurately predict which men with potentially non-lethal prostate cancers may eventually need treatment, say Johns Hopkins scientists.

“Our goal is to develop new biomarkers to select the right patients for the right therapy and know when the therapy should be delivered,” says Robert Veltri, Ph.D., associate professor of urology and oncology at the Johns Hopkins Brady Urological Institute, who adds that up to half of prostate cancer patients with low-grade, low-stage disease could safely be monitored rather than treated aggressively.

To make their prediction calculations, Veltri and his colleagues evaluated two tests on 71 men enrolled in a Johns Hopkins Proactive Surveillance program to monitor their small, low-grade cancers, none of which could be felt on physical examination.  The first is a blood test that combines three forms of PSA and is called the prostate health index (Phi), which was developed by Beckman Coulter and is not FDA-approved.  The second test involves examining biopsy tissue for the amount of DNA in cells – normal cells contain precisely two chromosomes, while the number of chromosomes in cancer cells varies.

Results show that the prostate health index was higher in 39 men whose annual biopsy showed worsening prostate cancer.  Also, in these men, abnormal DNA copies in cells from biopsied prostate tissue were over-expressed in cancerous areas as well as in adjacent non-cancerous areas.  The median time for following the study participants was about three and a half years.

“There are no outward signs that these small prostate cancers may be progressing -- men clinically feel the same and physicians are not likely to detect it on conventional imaging scans,” says Veltri. “We believe that close monitoring with the right biomarker tools may help to detect this shift in pathological stage.”

Veltri plans to continue studies with a larger group of patients over a longer time period.  He is also studying other biomarkers that include other types of PSA and the shape of nuclei in cells.

Funding for the study was provided by Early Detection Research Network and SPORE Prostate Grant of the NCI and the Patana Fund.

Sumit Isharwal, Lori Sokoll, Patricia Landis, Jonathan Epstein, Alan Partin, and H. Ballentine Carter from Johns Hopkins; Danil Makarov from Yale University; and Cameron Marlow, Johns Hopkins University Cell Core facility.

GENETICS EXPERT BERT VOGELSTEIN REVIEWS HISTORY, CHALLENGES AND FUTURE OF CANCER GENETICS RESEARCH

In a plenary session scheduled for Monday, April 19 at 8 a.m. at the AACR annual meeting in Washington, D.C., Bert Vogelstein, M.D., will offer his definition of the landscape of cancer genetics research for an audience of more than 10,000 scientists.

According to Vogelstein, he will review what scientists have learned about the cancer genome and his predictions for the field’s future.   He will discuss the total number of cancer genes discovered and how many genes have yet to be found.  He’ll also review the small number of core pathways through which all of these genes operate to turn normal cells into cancer cells.

Vogelstein says, “The single biggest challenge we face is how to apply this knowledge.  We now have a mountain of information about cancer and the most difficult part is figuring out how to use this knowledge to help people.”

Vogelstein is very clear about one research direction that he believes is currently undervalued but critical for overcoming this challenge:  “I believe that the primary way in which cancer deaths will be reduced in the future is through early detection and prevention rather than through the cure of advanced disease.”

 
 
 
 
 
 

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