When is it OK not to treat cancer?

The Hippocratic Oath advises doctors to first do no harm … words many doctors today are taking to heart when it comes to decisions about cancer treatment. Here’s Barry Petersen: 
Lisa Mann was readying for a double mastectomy when she consulted Dr. Laura Esserman and heard two critical words.
“Well, she said, ‘First of all, it’s highly treatable,’” Mann recalled.
“Sometimes doing less is just as important as doing more,” Dr. Esserman ad