You asked why Ramana got cancer when he was not exposed to any of the factors we know promote this disease. Cancer remains misunderstood for the most part. Of course researchers have made connections between toxins and poisons and the immune system, but other factors (known for millennia by Ayurvedic doctors) include emotions, doshas, environmental pollutants, ambient temperature, and the state of mind.

Ramana may have been an awakened holy man, but his body was as human and susceptible to illness as any other mortal. He obviously ignored his state of health in a number of ways according to his biography. In the same way, Siddhartha ignored his health and nearly died from starvation and neglect before he realized that a healthy body was the key to his enlightenment. On the other hand, Ramana’s awakening came prior to the decay of his body.

It's always curious how many people have tried to understand the very human qualities of these gurus, confusing the awakened mind with the state of the physical body. For instance, so many have questioned why Nisargadatta and his guru Siddharameshwar were chain smokers, or why Krishmamurti suffered from some sort of neurological disease and died from pancreatic cancer. This obsession is like staring at the finger pointing to the moon.