Prostate cancer patients who are overweight and have elevated insulin levels are at much higher risk of dying than other patients, a new Canadian study says. As part of their study, researchers at Montreal-based McGill University, in collaboration with Harvard University, analysed data from 2,546 American men who were diagnosed with prostate cancer during 24 years of follow-up. They found that those who were overweight (with body mass index of 25-29.9) or obese (body mass index of 30 or higher) before diagnosis were much more likely to die of the disease than those of normal weight, a statement by McGill University said. The study has been published in the October issue of The Lancet Oncology. It confirms the conclusions of a previous study that hinted at a possible link between prostate cancer mortality and obesity, the statement added. "It's a very strong effect," the statement quoted Michael Pollak of Alexander Goldfarb Chair in Medical Oncology at McGill University as saying. "Being overweight and having high insulin levels predicts bad outcome among men who have prostate cancer, and the strength of that relationship is remarkable. "In someone with metastatic prostate cancer, the magnitude of the good things that chemotherapy does may be swamped by the bad effects of being overweight. Or, to put it another way, the protective effect of being at your ideal body weight may be more significant than the benefits of chemotherapy," said Pollak. In reference to an earlier paper on the discovery of insulin receptors on prostate cancer cells, he said: "We have a high level of suspicion that the mediator for this effect is insulin. At this stage, it's not as if we can convict insulin in a court of law. However, it is a very serious suspect." "We did not do an intervention study; that's the next step, but it's a reasonable assumption that if obese prostate cancer patients lose weight, they may improve their outcome," Pollak added.