Naldemedine in Clinical Practice in Cancer Patients With Opioid Induced CONstipation: Clinical Outcomes and Patient Experience

• Naldemedine, an peripherally acting opioid antagonist (Drug): Participants will be treated with naldemedine 0.2 milligrams orally once daily as monotherapy for a duration of 14 consecutive days, following discontinuation of laxatives, as intervention for opioid-induced constipation (OIC).

Primary outcomes

• The change in Bowel Function Index (BFI) score [From enrollement to one week after initiation of naldemedine treatment]: Bowel Function Index (BFI) is a brief, three-item questionnaire assessing opioid-induced constipation over the past 7 days. It measures ease of defecation, sensation of incomplete evacuation and personal judgment of constipation, each rated on a 0-100 numerical rating scale. Scores are averaged and recalculated to a 0-100 scale; a score ≥30 indicates clinically significant opioid-induced constipation.

Secondary outcomes

• The change in Bowel Function Index (BFI) score [From enrollment to two weeks after initiation of naldemedine]
• A clinically meaningful improvement in constipation [From baseline to one week after treatment initiation and from baseline to two weeks after treatment initiation.]: The proportion of patients achieving a ≥12-point decline in the Bowel Function Index (BFI) score.
• The prevalence of persistent constipation, defined as a BFI score ≥ 30 [From enrollment to two weeks of treatment]
• The change in Patient Assessment of Constipation, Quality of Life (PAC-QoL) scores [From enrollment to two weeks of treatment with naldemedine]: The Patient Assessment of Constipation - Quality of Life (PAC-QoL) questionnaire is a 28-item questionnaire measuring the impact of constipation on daily functioning and well-being. Responses are given on a 5-point Likert scale, with higher scores indicating greater burden.
• Continuation of naldemedine [From enrollment to two weeks after initiation of naldemedine]
• Patient Satisfaction [From enrollment to two weeks of treatment with naldemedine]: Patient satisfaction is measured on an 11-point Likert scale (0 = "Not satisfied at all", 10 = "Very satisfied").
• Patient likelihood to recommend the use of naldemedine to other patients [From enrollment to two weeks of treatment with naldemedine]: Net Promoter Score (NPS): Based on the question: "How likely are you to recommend naldemedine to another patient?" (0 = "Not likely at all", 10 = "Very likely"). NPS is calculated as the percentage of promoters (scores 9-10) minus detractors (scores 0-6), yielding a score between -100 and +100.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Adult (≥18 years)
* A diagnosis of malignancy
* Daily use of opioids
* Use of laxatives
* Experiencing constipation, defined as a Bowel Function Index (BFI) score ≥30
* Able to complete a Dutch-language questionnaire
* Able to provide written informed consent

Exclusion Criteria:

* Use of other opioid antagonists in the last month
* Suspected (risk of) gastrointestinal perforation
* Participation in another study that may confound the results of this trial