Size and Aggressiveness of Prostate Cancer Tumors Related to Patient's Weight
Obesity is a known risk factor for the development of prostate cancer, and now researchers from Henry Ford Hospital in Detroit, Michigan have established a link between the size of the tumor and the aggressiveness of the cancer with patient weight. The study was presented June 2 at the 2010 American Urology Association's annual meeting in San Francisco.
The doctors established the relationship after analyzing the cases of over 3,300 patients (average age 60) who had cancerous prostate tumors that were surgically removed between October 2001 and October 2007. The subjects were divided into six categories of overweight or obesity according to their body mass index (BMI).
The researchers weighed each tumor and compared them to a database of prostate weight. Tumor volume is the size of the malignant tumor as a percentage of the space that it takes up in the affected tissue (the prostate gland). In each BMI category, without exception, they found that the patient’s weight was in direct correlation with the size of the tumor.
"As the patients' body mass index increased, the tumor volume increased synchronously," said study leader Dr. Nilesh Patil, of Henry Ford’s Vattikuti Urology Institute and Department of Radiology. "Based on our results, we believe having a larger percentage of tumor volume may be contributing to the aggressive nature of the disease in men with a higher BMI," he said.
There are two main theories about the association between obesity and the development of several common cancers, including prostate cancer.
First, many hormones that are involved in obesity also play a role in the initiation and promotion of cancer by stimulating tumor development and growth in the epithelial cells. These include excessive levels of the sex hormones estrogen and testosterone.
Second, external factors related to obesity may also influence cancer risk, including the consumption of a nutritionally-poor diet high in fat and low in fruits, vegetables and whole grains. Sedentary lifestyles may also contribute to both obesity and cancer risk.
According to the American Cancer Society, 192,280 new cases of prostate cancer were diagnosed in 2009. There were 27,360 deaths. Prostate cancer is the second most common type of cancer in American men behind skin cancer, and the second leading cause of cancer-related death (lung cancer is first).