The aim of the project is to investigate OIC in a real world / diverse group of patients with cancer.

The objectives of the project are to determine: a) efficacy of a treatment algorithm to manage OIC; b) efficacy of conventional laxatives to manage OIC; c) efficacy of PAMORAs / other interventions to manage OIC.

StOIC-2 is an observational study of routine clinical practice, and will involve four assessments over a period of 28 days (3 face to face; 1 telephone). Participants for StOIC 2 study will be identified from StOIC 1 study (CancerTrials.gov registry reference number - NCT04350112). Visit 1 for StOIC 2 study will correspond to the assessment for StOIC 1 study.

Patients will be managed according to a treatment algorithm (see below), which is based on a review of the evidence (and which is the basis of the Multinational Association for Supportive Care in Cancer (MASCC) guideline on the treatment of constipation in patients with advanced cancer). The decision to change treatment is based on efficacy / lack of efficacy (as determined by the Bowel Function Index (see below), or the development of adverse effects.

Step 1: Conventional Laxatives

• Choice of laxatives at the discretion of the clinical team
• Combination of softener and stimulant laxative
• Laxatives to be prescribed on a regular basis

Step 2: Peripherally acting mu opioid receptor antagonist (PAMORA)

• Choice of PAMORA at the discretion of clinical team
• Either oral naloxegol or subcutaneous methylnaltrexone
• PAMORA to be prescribed on a regular basis

Step 3: PAMORA + Conventional Laxatives

• Choice of combination at the discretion of the PI/clinical team
• Combination to be prescribed on a regular basis

Step 4: Other options

- Choice of other option at discretion of clinical team:

• Bowel cleansing preparations (e.g. Picolax)
• Suppositories
• Enemas
• Manual evacuation
• Other drugs (e.g. lubiprostone, prucalopride)

The following data will be collected: a) demographic data - age, gender, ethnicity; b) cancer diagnosis; c) opioid medications - drug, formulation, dose; d) laxative medications - drug, formulation, dose (every visit); e) Eastern Cooperative Oncology Group performance status.

The participants will also be asked to complete;

1. Bowel Function Index (BFI) - every visit. The BFI is a validated, 3 item, patient reported tool for assessing the treatment of OIC. A BFI score of > 30 indicates suboptimally treated OIC.
2. Patient Assessment of Constipation - Quality of Life Questionnaire (PAC-QOL) - first and last visit. The PAC-QOL is a validated, 28 item, patient reported tool for assessing the impact of constipation over time.
3. Memorial Symptom Assessment Scale - Short Form (MSAS-SF) - first and last visit. The MSAS-SF is a validated, 32 item, patient reported tool for assessing physical and psychological symptoms in cancer patients.

Data will also be collected on adverse effects from medication / interventions, and reasons for withdrawal from the study.

Inclusion Criteria:

• As per StOIC 1: age > 18yr; diagnosis of cancer; diagnosis of cancer pain; receipt of regular opioids for at least one week
• Diagnosis of OIC as defined by the Rome IV criteria (Lacy et al, 2016)
• Diagnosis of inadequately treated OIC as defined by BFI > 30

Exclusion Criteria:

• As per StOIC 1: inability to give informed consent; inability yo complete questionnaire
• Prognosis > 1 month

Participants may be inpatients, outpatients, day centre patients and home care patients at the sites conducting the research

Currently, there are no plans to make IPD available to other researchers