Lyle Alzado was featured in several Sports Illustrated articles, before and after his diagnosis of cancer.
After he was diagnosed with cancer, he came clean and admitted that he used steroids since he was 18 or so. The most important factor to consider is that Lyle never stopped taking steroids. Indeed, he took steroids in large doses continually for twenty years, with no break or time off.
In all likelihood, the chronic steroid abuse led to severe liver disease, followed by the development of cancer. Some people say he died of brain cancer, but it is more likely that the tumors in his brain were metastases from his primary liver cancer (liver tumors are well known to metastasize to brain).
Alcohol is a good analogy. Many many people consume alcohol in excess on a infrequent basis. However, if you drink alcohol to excess regularly for decades, your risk of developing liver cancer (among others) increases dramatically.
Anyway, I guess the take-home point from this thread is: 'Try to hold off on doing a 20 year cycle as there may be a few health problems!'