Prostate cancer prognosis worse in obese men

NEW YORK (Reuters Health) — Prostate cancer diagnosis tends to be delayed and surgical treatment more difficult in obese men than in lean men, according to two studies.

The primary reason for the later diagnosis, and consequently poorer prognosis, seems to be that the PSA test used to screen for prostate cancer is "biased" against obese men, according to researchers. The problem, they explain, may stem from obese men's larger blood volume, which dilutes their PSA levels. High blood levels of PSA — or prostate specific antigen — can signal the presence of a prostate tumour.

"We know that obese men tend to have lower PSA values than their normal-weight counterparts, possibly caused by larger blood volumes which dilute their readings," Dr. Stephen J. Freedland, who led the studies, said in a written statement.

"Now we know some of the real implications of this — that these men are at a disadvantage in terms of prognosis compared to normal-weight men."

Freedland, of Duke University Medical Center in Durham, North Carolina, and his colleagues report their findings online in the journal BJU International. In one study, the researchers looked at the outcomes of nearly 3,400 prostate cancer patients who had undergone surgical removal of the prostate between 1988 and 2007. Some had had their cancer detected by PSA, while the rest had had it discovered during a digital rectal exam.

Overall, Freedland's team found, obese men were more likely to have more-aggressive tumours and to suffer a cancer recurrence after surgery. However, the link between weight and disease progression was limited to men treated since 2000, when PSA screening had become the norm.

By contrast, obesity had no effect on the risk of progression for cancers detected by digital rectal exam. The findings support the notion that PSA testing, in particular, confers a bias against obese men, according to Freedland.

In the second study, the researchers found that obese prostate cancer patients tend to have a higher rate of "positive surgical margins" after prostate removal — which means the odds are higher that some tumour cells were left behind.

"The aggressiveness of obese men's tumours, coupled with the fact that they may be more difficult to remove, is like a double whammy for being obese," Dr. Jayakrishnan Jayachandran, another researcher on the studies, said in a statement.

The findings of both studies, according to Freedland, build up the case for developing alternative prostate cancer screening methods for obese men — or for lowering the PSA threshold for these patients.

"The least we can do is find a way to level the playing field when it comes to diagnostic tools," Freedland said.

Fever-related seizures in children rarely fatal

NEW YORK (Reuters Health) — Although fever-related seizures can prove fatal for some children, such deaths are nonetheless extremely rare, a large study from Denmark shows.

The findings, reported in Saturday's issue of The Lancet medical journal, should be reassuring for parents, researchers say. About two to five percent of children younger than five will suffer at least one febrile seizure — generalized convulsions caused by elevated body temperature. But studies on the condition have been too small to estimate how many children actually die from fever-related seizures.

For the new study, Dr. Mogens Vestergaard, from Aarhus University in Denmark, and colleagues analysed data on nearly 1.7 million children born in Denmark between 1977 and 2004.

They identified 8,172 children who died during the study period, including 232 deaths among more than 55,000 children with a history of febrile seizure.

Overall, the researchers found, children who suffered a febrile seizure were nearly twice as likely as children in the general population to die during the two years following the seizure. Beyond that point, there was no increased risk.

And while the short-term risk of death was elevated, the actual number of children who died was extremely low, Vestergaard's team stresses.

Over two years, they say, there would be two deaths per 1,500 children with febrile seizures, versus one death per 1,500 children in the general population. Moreover, the study found, much depends on the type of febrile seizure.

Children who suffered a "simple" seizure — lasting no more than 15 minutes, without recurrence in 24 hours — had a death rate similar to children in the general population.

Instead, the risk was linked specifically to so-called complex seizures, which are longer-lasting or arise again within 24 hours; often, deaths among these children were related to pre-existing neurological abnormalities.

The findings seem to "refute, for infants and children who have simple febrile seizures, the idea of a shared cause between febrile seizures and sudden death," Dr. Maitreyi Mazumdar, from Children's Hospital Boston, writes in a related editorial.

At the same time, she adds, the results reinforce the message that children with complex seizures and neurologic abnormalities should be followed closely by their doctors.