A sign proclaiming "No more cancer" is set up in Washington

From Reporter Louise Schiavone

WASHINGTON (CNN) -- Cancer patients, survivors and their advocates gather this weekend for a massive march against the disease. But the event is also a chance to lobby Congress for a bigger share of the $13.6 billion the government will spend this year on medical research.

Both cancer and AIDS receive billions in funding. However, if the money spent on research was proportionate to the number of people affected by a disease, both illnesses might fare very differently.

Many doctors and specialists say they believe the budget for the National Institutes of Health is a testament to effective lobbying.

In 1996, with more than a half million cancer deaths, the National Institutes of Health dedicated $2.5 billion to cancer research. With over 32,000 AIDS deaths, $1.4 billion went to AIDS research. And with more than three-quarters of a million heart disease fatalities, $851 million went to cardiovascular research.

A blue-ribbon panel appointed by the Institute of Medicine broke it down this way: For every $10 spent per cancer death on cancer research, $110 is spent per AIDS death on AIDS research and $3 is spent per heart disease death on heart disease research.

Cardiologists say most people don't realize heart disease is the nation's top killer, particularly because there's no organized popular lobby for it.

"Those groups that speak the loudest or strike a particular note among the public or among legislators may get a proportion of the research dollar that is out of proportion to the number of victims of that particular disease," said Dr. Staurt Seides, a past president of the Washington American Heart Association.

Workers set up a stage for the upcoming event Friday in Washington

While refusing to spell out priorities of its own, the Institute of Medicine panel concedes that while the most common route to more research dollars is to lobby Congress, the outcome doesn't always serve medicine.

"The results is sometimes Congress doesn't act or that Congress acts in a way that is less than the most effective distribution of funds available.

So while cancer, AIDS and heart disease are big killers, scientists say there are other, equally devastating diseases where breakthroughs could be imminent.