Obese Men at Risk of Metastic Prostate Cancer

Obese Men at Risk of Metastic Prostate Cancer

ORLANDO—Overweight and obese men are at increased risk of dying of prostate cancer,

a new study presented at the 2005 Multidisciplinary Prostate Cancer Symposium

has shown. According to lead investigator Jing Ma, MD, PhD, of Harvard

MedicalSchool, patients with prostate cancer who are obese have a greater risk of

dying from prostate cancer than patients who are not obese. Recent studies have also

observed that obesity at the time of diagnosis seems to be linked to the recurrence of

cancer after surgery, she reported. This prospective survival analysis of

body mass index (BMI) and prostate cancer mortality in the Physicians’ Health Study

was initiated to determine whether elevated BMI or obesity would predict the cancer

severity or risk of dying of prostate cancer. The investigators calculated BMI from

body weight and height measurements obtained when the study began in 1982.

They then categorized the 2144 men enrolled in the study who developed

prostate cancer into 3 groups, based on BMI: normal weight, <25 ; overweight, 25

to 29.9, and obese, ≥30. During the 21- year follow-up period, 223 men died of

prostate cancer. Dr Ma concluded that men who were overweight before being diagnosed with

prostate cancer had a 30% higher risk of dying from it, and obese men had > 2-fold

higher risk, compared with normal-weight men. “Obese men are more likely to have

metastatic disease, suggesting either delayed diagnosis or, biologically, probably

they have more aggressive forms of cancer,” Eric Klein, MD, of the ClevelandClinic Foundation, noted that fat cells are living things, and they make substances

that promote growth of other cells, probably including some cancers,

not only prostate cancer but colon cancer and several other kinds as well. There

are some data, although they are not uniform, that obesity depresses prostatespecific

antigen (PSA) levels. “So if you are fat and you get your PSA levels

checked and the PSA level is low, you are less likely to be biopsied, allowing

the cancer to go undetected,” Dr Klein added.