"I think the question reflects a human desire to revisit events that occurred over a lifetime, and speculate whether a change in course could have avoided an untoward outcome.

In truth, though, except in very rare cases, it is almost impossible to say that a specific environmental exposure triggered a given person’s cancer. The majority of cancers arise randomly, as if thumbing their nose at our collective need to find a cause.

But that doesn’t stop me from trying, during the part of the clinic visit when it’s my turn to ask the questions. And sometimes, I even convince myself that I have uncovered that nugget of truth that explains disease".