Why bladder cancer is deadlier in some

Bladder cancer (BC) is much more likely to be deadly for women and African-Americans, but the reasons long believed to explain the phenomenon account for only part of the differences for such patients compared to their white and male counterparts. These findings, published in the 1st January issue of Cancer (2009;115:68-74), raise a question for doctors and patients: if age, tumour type and stage of the disease upon diagnosis do not account for the increased lethality of the disease in women and African-Americans, then what does?

It is a big question facing researchers in this area where the disease is more lethal in those patients who are less likely to get it. Men are more than three-times as likely as women to develop the disease, and white people are nearly twice as likely to get the disease as African-Americans. Yet, once the disease is present, it is far deadlier in women and African-Americans.

In the new study, scientists at the University of Rochester Medical Center have shown for the first time that the factors traditionally thought to be responsible for the differing course are responsible for only about one-third of the difference between white men and women, and up to two-thirds of the difference between African-Americans and their white counterparts.

To perform the study, researchers analysed the records of 101,249 patients who were diagnosed with BC from 1990 to 2003 as part of the SEER (Surveillance, Epidemiology, and End Results) programme. The team found that in the first year after diagnosis, women were anywhere from approximately 80 to 114 per cent more likely to die from the disease than their male counterparts. That increase was slightly lower in year two, when women were around 52 to 55 per cent more likely to die.

When it came to race, the researchers found that African-Americans were approximately 73 to 103 per cent more likely than their white counterparts to die from the disease within the first two years after diagnosis, and around 40 to 117 per cent more likely to die three or four years after diagnosis. The investigators then examined the data to try to uncover the reasons behind these differences. The team found that the factors traditionally thought to be responsible accounted for only approximately 30 per cent of the difference between the genders among white people, and around 50 to 70 per cent of the differences between the races and genders among African-Americans.

The study's authors speculate about other factors that might be responsible for the differences, though they say that further study is necessary to know for sure. Some of the other issues that might play a role include the choice of treatment, differences among tumours that were not taken into account in the study and access to healthcare. The authors believe that poorer access to healthcare is a clear cause of the higher mortality rates for African-Americans. When it comes to gender, some of the differences are likely to be caused by factors that are not currently understood, such as hormonal differences. But a factor that is known to play a key role is people's reaction when they see blood in their urine. Men are more likely than women to notice blood in their urine, to think it is abnormal, and to report it to doctors and even then, when it is reported, doctors are 65 per cent more likely to refer men than women to urologists.

Matthew Dennis - Editor, Cancer Drug News