To measure the primary endpoint patients will be asked to score the worst pain in the past 24 hours on a numeric rating scale (NRS) from 0-10. In addition, patients will be asked to list their usual pain medication and the escape medication they used the previous 24 hours. These questions are derived from the Brief Pain Intervention (BPI) score, which is advised by the International Consensus Statement for Bone Metastasis Research. The BPI is a pain assessment tool for use with cancer patients developed by the Pain Research Group of the World Health Organization (WHO) Collaborating Centre for Symptom Evaluation in Cancer Care and is also available in Dutch. However, multiple questions are similar to questions in the European Organization for Research and Treatment of Cancer (EORTC) Quality of life questionnaire for palliation (QLQ-PAL15) and EORTC Quality of life questionnaire for bone metastases (QLQBM-22) (described below). Thus to spare patients answering the same questions twice, the investigators have selected only 2 questions from the BPI.