Among the recent research grants awarded by the National Cancer Institute is one for a study asking whether people who are especially responsive to good-tasting food have the most difficulty staying on a diet. Many other grants involve biological research unlikely to break new ground. For example, one project asks whether a laboratory discovery involving colon cancer also applies to breast cancer. But even if it does apply, there is no treatment yet that exploits it. The cancer institute has spent $105 billion since President Richard M. Nixon declared war on the disease in 1971. The American Cancer Society, the largest private financer of cancer research, has spent about $3.4 billion on research grants since 1946. Yet the fight against cancer is going slower than most had hoped, with only small changes in the death rate in the almost 40 years since it began. One major impediment, scientists agree, is the grant system itself. It has become a sort of jobs program, a way to keep research laboratories going year after year with the understanding that the focus will be on small projects unlikely to take significant steps toward curing cancer. 'These grants are not silly, but they are only likely to produce incremental progress,' said Dr. Robert C. Young, chancellor at Fox Chase Cancer Center in Philadelphia and chairman of the Board of Scientific Advisors, an independent group that makes recommendations to the cancer institute. The reviewers choose such projects because, with too little money to finance most proposals, they are timid about taking chances on ones that might not succeed. The problem, Young and others say, is that projects that could make a major difference in cancer prevention and treatment are all too often crowded out because they are too uncertain. In fact, it has become lore among cancer researchers that some game-changing discoveries involved projects deemed too likely to fail and were therefore denied federal grants, forcing researchers to struggle mightily to continue. Even top federal cancer officials say the system needs to be changed. 'We have a system that works overall pretty well, and is very good at ruling out bad things -- we don't fund bad research,' said Dr. Raynard S. Kington, acting director of the National Institutes of Health, which includes the cancer institute. 'But given that, we also recognize that the system probably provides disincentives to funding really transformative research.' 