Collard greens trump KFC

Poor prostate cancer prognosis linked to fat

By Jenny Lipton

Obesity boosts the risk of more aggressive prostate cancer and higher recurrence rates after radical prostatectomy, according to reports from a recent issue of the Journal of Clinical Oncology from two independent research groups. Both research teams think that obesity could at least partly explain why non-white men are often at greater risk for prostate cancer outcomes.

The first group, headed by Dr Christopher L Amling in San Diego followed over 3,000 men who'd had radical prostatectomies between 1987 and 2002. One out of five patients was considered obese, defined by a BMI over 30 kg/m2. Average prostate specific antigen (PSA) levels were significantly higher in the obese men, at 6.3, compared to 6.1 in the lower BMI group. The heavier guys also had much higher Gleason scores, tumour cells extending into the margins, and more chance of a biochemical recurrence. When the researchers looked at racial differences, they discovered that not only were black men significantly more obese overall, they were also coming in with prostate cancer at a younger age. Not only that, their tumours were more aggressive types, with higher grades and staging.

The second study ran from 1988 to 2002, and was led by Dr Stephen J Freedland from Johns Hopkins School of Medicine in Baltimore. This investigation followed 1,752 patients who'd also had their cancerous prostates surgically removed. Like the first group of researchers, this second team also found that on average, the black men in their research group were more likely to be obese than the white patients.

And it looked like the problem was getting worse -- in the last 10 years of the study, fat stats had doubled in these patients. Again, the heavier men had developed cancer at a younger age, and their biopsies and Gleason scores were more ominous. If the BMI was above 35 -- indicating severe obesity -- the likelihood of the PSA shooting up was also much worse. However, when the data from this study were analyzed, the researchers found that obesity, but not race, rated as an independent risk factor.

Epidemiological studies often -- but not always -- report that when a man is fat, he's more likely to get prostate cancer. But where the link is consistent is in the outcome: extra fat is always associated with a worse outcome. In study after study, obesity is found to worsen the risk of a prostate cancer mortality. A commentary on the issue by Dr Alfred I Neugut, of Columbia University in New York, reminds us that BMI is modifiable. With the extra burden of this disease on black men, he suggests that programs be set up to encourage men in the black community to cut out the calories.

Prostate cancer makes up about 30% of all cancers. There's not much hope for a complete cure unless the tumour is removed or destroyed before it grows beyond the encapsulated stage. Then either surgery or radiation can do the trick. Management decisions are normally made based on tumour staging. Staging is based on the tumour type (Gleason grade/ score), node involvement, biomarkers, and evidence of metastasis. Age, family history, race, and dietary habits have all been identified as other possible risk factors for developing the disease.