Claiming to have discovered a miraculous treatment for cancer, Dr. Luigi Di Bella, an 85 year old physiologist in Modena, has for the last year held center stage in Italy, fighting and almost winning-an astonishing battle for legitimacy. Hailed by some as a savior, derided by others as a dangerous crackpot, Dr. Di Bella suffered a setback last week when government tests of his method indicated that it did not work. They also shed dramatic light on how human desperation and a huge lobbying campaign forced the Italian public health system to provide a treatment without any proof of its eficacy.