Obesity linked to aggressive prostate cancer

December 22, 2003

Alexandria, VA - Obese men with prostate cancer are more likely to have aggressive tumors and to experience cancer recurrence after surgery compared to men of normal weight or those who are overweight but not obese, according to two new studies. Although more research is needed, the findings suggest that men may be able to modify their risk of aggressive prostate cancer by maintaining a healthy weight. The results of both studies will be reported December 22 online in the Journal of Clinical Oncology (JCO).

"The primary role of obesity in prostate cancer is still unclear, but it appears to induce the development of more aggressive tumors," said Christopher L. Amling, MD, of the Naval Medical Center's Department of Urology in San Diego and lead author of one of the studies. "I would advise patients to maintain a normal body weight to limit the possibility that they would develop clinically significant, more aggressive prostate tumors."

Both studies examined the relationship between obesity and prostate cancer recurrence in large samples of men with localized prostate cancer who had undergone surgery to remove the prostate - a procedure called radical prostatectomy.

While obesity rates in the general adult population are similar between African-American and Caucasian men, both studies found that obese patients in the study groups were more likely to be African American. This finding may help explain why African-American men with prostate cancer generally have more aggressive tumors and worse outcomes compared to Caucasians.

"We suspect that worse outcomes among African-American men with prostate cancer are related to obesity rather than race. If we can target obesity in the African-American community, we may be able to reduce the burden of prostate cancer among black men," explained lead author of the second study, Stephen J. Freedland, MD of the multi-institution Shared Equal Access Regional Cancer Hospital (SEARCH) Database and currently at the James Buchanan Brady Urological Institute at the Johns Hopkins University School of Medicine.

While other studies have indicated that obesity influences cancer recurrence for women diagnosed with breast cancer, the current studies are the first to investigate the relationship between obesity and prostate cancer recurrence after surgery.

Dr. Amling's study involved 3,162 prostate cancer patients, including 19% who were obese. Obesity was defined as a body mass index of 30 kg/m2 or higher - the equivalent of a 5 foot, 10 inch man weighing 210 pounds or more. In this study, obesity was associated with an elevated Gleason score - a method used to classify the aggressiveness of prostate tumors - and a higher rate of cancer recurrence (determined by elevated PSA levels). African-American men in the study were more likely to be obese (27% vs. 18% of white men), have higher cancer recurrence rates, and more aggressive disease.

Dr. Freedland's study involved 1,106 patients, including 22% who were obese. In this study, mild obesity was also defined as a body mass index of 30 kg/m2 or greater. However, moderate and severe obesity was defined as a body mass index of 35 kg/m2 or greater- equivalent to a 5 foot, 10 inch man weighing 245 pounds or more - and was associated with a higher Gleason score and higher rates of cancer recurrence (determined by rising PSA levels). Men with a BMI of 35 kg/m2 or greater had a 60% risk of cancer recurrence within 3 years, the investigators found. In this study, 31% of African-American men were obese, compared to 21% of Caucasian men.

Both Drs. Amling and Freedland suggest that proteins and hormones stored in body fat - such as leptin and insulin-like growth factor-1 - may promote prostate tumor growth in obese men. Also, obese men typically have lower testosterone levels and higher estrogen levels, which may encourage the growth of cancer. In addition, diets high in fat may promote tumor growth.

An accompanying editorial in the JCO commends the studies for presenting a provocative thesis relating obesity to prostate cancer aggressiveness and outcome.

"In light of the rising incidence of obesity worldwide, identifying obesity as a risk factor for aggressive prostate cancer is important, since it may be one of the few modifiable risk factors for prostate cancer," said Alfred I. Neugut, MD, PhD, Professor of Medicine and Epidemiology, and Head of Cancer Prevention at Columbia University's Herbert Irving Comprehensive Cancer Center and author of the editorial, "The Skinny on Obesity and Prostate Cancer Prognosis."

"The number of prostate cancer survivors is steadily increasing," Dr. Neugut added, "and it will be important to investigate if weight loss and other lifestyle changes can improve prognosis in those already diagnosed with prostate cancer."

"Impact of Obesity on Biochemical Control Following Radical Prostatectomy for Clinically Localized Prostate Cancer." Stephen J. Freedland et al, Johns Hopkins School of Medicine, Baltimore, MD.

"Pathologic Variables and Recurrence Rates As Related to Obesity and Race in Men With Prostate Cancer Undergoing Radical Prostatectomy." Christopher L. Amling et al, Naval Medical Center, Department of Urology, San Diego, CA.
-end-
The Journal of Clinical Oncology is the semi-monthly peer-reviewed journal of the American Society of Clinical Oncology (ASCO), the world's leading professional society representing physicians who treat people with cancer.

ATTRIBUTION TO THE JOURNAL OF CLINICAL ONCOLOGY IS REQUESTED IN ALL NEWS COVERAGE.

For the full text of any JCO article, contact 703-519-1423 or 212-584-5014.

To view a medical illustration of the prostate, please visit http://www.asco.org/ac/1,1003,_04-005-00_12-002611-00_18-0030786-00_19-000-00_20-001,00.asp.

American Society of Clinical Oncology

Related Prostate Cancer Articles from Brightsurf:

Low risk of cancer spread on active surveillance for early prostate cancer
Men undergoing active surveillance for prostate cancer have very low rates - one percent or less - of cancer spread (metastases) or death from prostate cancer, according to a recent study published in the Journal of Urology®, an Official Journal of the American Urological Association (AUA).

ESMO 2020: Breast cancer drug set to transform prostate cancer treatment
A drug used to treat breast and ovarian cancer can extend the lives of some men with prostate cancer and should become a new standard treatment for the disease, concludes a major trial which is set to change clinical practice.

Major trial shows breast cancer drug can hit prostate cancer Achilles heel
A drug already licensed for the treatment of breast and ovarian cancers is more effective than targeted hormone therapy at keeping cancer in check in some men with advanced prostate cancer, a major clinical trial reports.

The Lancet: Prostate cancer study finds molecular imaging could transform management of patients with aggressive cancer
Results from a randomised controlled trial involving 300 prostate cancer patients find that a molecular imaging technique is more accurate than conventional medical imaging and recommends the scans be introduced into routine clinical practice.

Common genetic defect in prostate cancer inspires path to new anti-cancer drugs
Researchers found that, in prostate cancer, a mutation leading to the loss of one allele of a tumor suppressor gene known as PPP2R2A is enough to worsen a tumor caused by other mutations.

First prostate cancer therapy to target genes delays cancer progression
For the first time, prostate cancer has been treated based on the genetic makeup of the cancer, resulting in delayed disease progression, delayed time to pain progression, and potentially extending lives in patients with advanced, metastatic prostate cancer, reports a large phase 3 trial.

Men taking medications for enlarged prostate face delays in prostate cancer diagnosis
University of California San Diego School of Medicine researchers report that men treated with medications for benign prostatic hyperplasia (enlarged prostate) experienced a two-year delay in diagnosis of their prostate cancer and were twice as likely to have advanced disease upon diagnosis.

CNIO researchers confirm links between aggressive prostate cancer and hereditary breast cancer
The study has potential implications for families with members suffering from these types of tumours who are at an increased risk of developing cancer.

Distinguishing fatal prostate cancer from 'manageable' cancer now possible
Scientists at the University of York have found a way of distinguishing between fatal prostate cancer and manageable cancer, which could reduce unnecessary surgeries and radiotherapy.

Researchers find prostate cancer drug byproduct can fuel cancer cells
A genetic anomaly in certain men with prostate cancer may impact their response to common drugs used to treat the disease, according to new research at Cleveland Clinic.

Read More: Prostate Cancer News and Prostate Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.