question: my friend just wt through postrate cancer chemo not radiation because the cancer spread to bones but not organs. Now after being cancer free according to testing he has a black spot on his heart.  he says he is going to probably have to have surgery.  not certain one more test to go.  stress test, poor circulation in legs echogram he failed .  what do this black spot means?  blood , heart attack or cancer.  all blood work is clear of cancer