Objective: To study the preferences of women with deep endometriosis (DE) with bowel involvement when they have to choose between conservative (medication) or surgical treatment. Design: Labelled discrete choice experiment (DCE). Setting: Dutch academic and non-academic hospitals and online recruitment. Population or Sample: A total of 169 women diagnosed with DE of the bowel. Methods: Baseline characteristics and the fear of surgery were collected. Women were asked to rank attributes and choose between hypothetical conservative or surgical treatment in different choice sets (scenarios). Each choice set offered different levels of all treatment attributes. Data were analysed by using multinomial logistic regression. Main Outcome Measures: The following attributes – effect on/risk of pain, fatigue, pregnancy, endometriosis lesions, mood swings, osteoporosis, temporary stoma and permanent intestinal symptoms – were used in this DCE. Results: In the ranking, osteoporosis was ranked with low importance, whereas in the DCE, a lower chance of osteoporosis was one of the most important drivers when choosing a conservative treatment. Women with previous surgery showed less fear of surgery compared with women without surgery. Low anterior resection syndrome was almost equally important for patients as the chance of pain reduction. Pain reduction had higher importance than improving fertility chances, even in women with desire for a future child. Conclusions: The risk of developing low anterior resection syndrome as a result of treatment is almost equally important as the reduction of pain symptoms. Women with previous surgery experience less fear of surgery compared with women without a surgical history. Tweetable Abstract: First discrete choice experiment in patients with deep endometriosis.

Objective: To study the experiences, considerations, and motivations of patients with endometriosis in the decision-making process for deep endometriosis (DE) treatment options. Design: Qualitative study using semi-structured in-depth focus group methodology. Setting: University medical center. Patient(s): A total of 19 Dutch women diagnosed with DE between 27 and 47 years of age. Intervention(s): Not applicable. Main Outcome Measure(s): Focus group topics were disease impact and motives for treatment, expectations of the treatment process, and important factors in the decision process. Result(s): Women reported that pain, fertility, and strong fear of complications are important decisive factors in the treatment process. The goal of conceiving a child is considered important, however, sometimes doctors emphasize this topic too much. It emerged that complication counseling is frequently about surgical complications, whereas side effects of hormonal treatments are neglected. Shared decision making and information about treatment options, complications, and side effects are not always optimal, making it difficult to make a well-considered choice. Despite negative experiences encountered after surgery, the positive effect of surgery ensures that most women do not regret their choice. Conclusion(s): In the treatment decision process for patients with DE, pain is almost always the most important decisive factor. The wish to conceive and strong fear of complications can change this choice. Doctors should understand the importance of fertility for the majority of women, but, also, if this is not considered paramount, respect that view. To improve shared decision making, exploration of treatment goals, training of healthcare providers, and better patient information provision are desirable.