Simple SummaryMyeloma, a blood cancer, is rare and hard to diagnose. People often suffer irreversible organ damage by the time of diagnosis. Myeloma is preceded by a premalignant phase that is easily identifiable on a blood test. Currently, there is no screening for this, because most people do not progress to myeloma. We aimed to inform guidelines and screening by refining our understanding of how patients developing myeloma describe their symptoms and how those symptoms relate to organ damage. We found that patients rarely describe ‘bone pain’ but simply ‘pain’. Low-impact crush fractures of the backbones appear to be under-recognised as abnormal. At least 30% of patients have irreversible organ damage at diagnosis. People who developed myeloma fared better if they had previously been diagnosed to have the premalignant condition. Screening based on certain symptoms, possibly combined with imaging and laboratory results, may speed up the diagnosis of myeloma.AbstractMultiple myeloma (MM) patients risk diagnostic delays and irreversible organ damage. In those with newly diagnosed myeloma, we explored the presenting symptoms to identify early signals of MM and their relationships to organ damage. The symptoms were recorded in patients’ own words at diagnosis and included diagnostic time intervals. Those seen by a haematologist >6 months prior to MM diagnosis were classified as precursor disease (PD). Most (962/977) patients provided data. Back pain (38%), other pain (31%) and systemic symptoms (28%) predominated. Patients rarely complain of ‘bone pain’, simply ‘pain’. Vertebral fractures are under-recognised as pathological and are the predominant irreversible organ damage (27% of patients), impacting the performance status (PS) and associated with back pain (odds ratio (OR) 6.14 [CI 4.47–8.44]), bone disease (OR 3.71 [CI 1.88–7.32]) and age >65 years (OR 1.58 [CI 1.15–2.17]). Renal failure is less frequent and associated with gastrointestinal symptoms (OR 2.23 [CI1.28–3.91]), age >65 years (OR 2.14 [CI1.28–3.91]) and absence of back pain (OR 0.44 [CI 0.29–0.67]). Patients with known PD (n= 149) had fewer vertebral fractures (p= 0.001), fewer adverse features (p= 0.001), less decline in PS (p= 0.001) and a lower stage (p= 0.04) than 813 with de novo MM. Our data suggest subgroups suitable for trials of ‘symptom-directed’ screening: those with back pain, unexplained pain, a general decline in health or low-impact vertebral compression fractures.