That's a very good question.
It's hard to know, because many women with endometriosis are very asymptomatic. That even means that people who have horrible disease—when we enter the pelvis, they have stage four endometriosis—may be asymptomatic. They may have no symptoms.
That being said, if we look at studies, probably 15% to 20% of endometriosis cases are more severe, so they're stage three to four. Among those people, it's hard to say when they first developed the severity of the disease, because often, we catch it when it's already severe or when it's superficial. We don't have enough data to follow and see what the timeline is that it takes for someone with superficial endometriosis to develop something more severe.
Every person is different. Endometriosis in some women recurs very quickly after surgery, versus other people, who don't see it recur. I think all of this points toward the need to have more funding for research so that we can elucidate these answers and give better care for patients.