Is adolescent endometriosis a progressive disease that needs to be diagnosed and treated?

In this issue you will find an Opinion article by three icons of endometriosis (Brosens et al., 2013). They present their ideas on the early stages of disease, in adolescents. Although there exists very little robust evidence to support many of their claims (as they recognize themselves), we decided to publish their manuscript to draw attention to the complex issue of preventive reproductive health care in this vulnerable group of young women. The case reports and clinical observations that are at the basis of their Opinion paper are confounded by diagnostic and verification bias: Why did these young girls attend a doctor in the first place? Why, and in which of them, was it decided to perform a laparoscopy? How was follow-up taken care of? How was disease progression established? I will leave it up to you to form your own opinion, but I would like to address one of the important issues that Brosens and co-workers mention: Is endometriosis a progressive disease? Some clue may be gained by looking at (adult) control patients in randomized clinical trials, with laparoscopies before and after a period without treatment. Seven such studies exist (table); they show 42% spontaneous regression, 29% stable disease, and 29% progression. So, overall, 71% did not progress in the period (of usually 6 months) between laparoscopies. There was no way of predicting who would progress and who would not. For discussion. Natural course of disease between first and second look laparoscopy in untreated patients. Natural course of disease between first and second look laparoscopy in untreated patients.