CHARLOTTE, N.C. – Obese men face an increased risk of dying from prostate cancer and doctors should be especially thorough when checking these patients for the disease, a new study suggests.
Because the size of the prostate gland is larger in obese men, prostate cancer can be 20 percent to 25 percent harder for doctors to detect, according to Dr. Stephen Freedland, a surgeon at Duke University Medical Center in Durham and lead author of the study.
The findings are being published in the February issue of the Journal of Urology.
Because biopsies sample less of the total tissue in a larger prostate, it's harder to spot hidden cancer, Freedland said.
The study surveyed medical records of some 1,400 men diagnosed with cancer whose prostates were surgically removed from 1998 to 2004 at Veteran's Administration hospitals in California and Georgia and at the San Diego Naval Hospital.
Prostate cancer is the second most common cancer afflicting American men. In its most recent estimates, the American Cancer Society projected that 232,000 American men would be diagnosed with the disease and 30,000 would die from it in 2005.
Previous studies have shown that obese men diagnosed with prostate cancer were 20 percent to 35 percent more likely to die from it than men of normal weight. Obesity is based on a height and weight formula; a 6-foot man would be obese if he weighed 222 pounds or more.
Prostates removed from the patients in the study were weighed. The 245 men in the sample who were moderately obese had an average prostate weight of 1.4 ounce. Normal-sized prostate glands weigh half to three-fourths as much.
Dr. Durado Brooks, the American Cancer Society's prostate cancer specialist, said the study helps deepen understanding of the link between obesity and prostate cancer.
"It's one more small piece of the puzzle," he said. "Studies like this help to slowly build a clearer picture."
Other work has given contradictory indications about whether obese men face an increased or decreased risk of prostate cancer, Brooks said. And it's unclear whether the increased likelihood that an obese man will die of prostate cancer is due to problems with early detection or a more aggressive form of the cancer, he said.
Freedland's study recommends doctors do thorough rectal exams of obese men and conduct lab tests that can tip off the presence of cancer.
The study showed that prostate enlargement actually leveled off among morbidly obese men due to decreased testosterone levels.