Two simple blood tests may help earlier detection of a rare cancer
A study of general practice electronic medical records up to five years before the diagnosis of the rare cancer myeloma has suggested that abnormal values for two simple tests, haemoglobin and plasma viscosity (or erythrocyte sedimentation rate), in patients with the early non-specific symptoms of myeloma should prompt urgent blood and urine tests to expedite diagnosis. Normal values for both tests can usually rule out the diagnosis.
Myeloma is a malignant tumour of plasma cells in the bone marrow, often in multiple sites. The tumour cells, derived from a single antibody-producing cell, secrete only one type of antibody in large amounts that can be detected in plasma (blood) by electrophoresis. In many cases a small part of the antibody (Bence Jones protein) can be detected in urine. Positive tests for these paraproteins should lead to urgent referral for further investigation and treatment.
To investigate why the diagnosis of myeloma is often delayed, researchers from the Department of Health Care Sciences, University of Oxford, the University of Exeter Medical School and Chiddenbrook Surgery, Crediton, Devon examined the General Practice Research Database primary care electronic records of 2,703 patients aged over 39 years who were diagnosed with myeloma between 2000 and 2009, and also those of 12,157 age, sex, and general practice-matched controls. Specific symptoms suggesting advanced disease, such as fractures, weight loss, and nausea usually led to diagnosis and referral within a few months. However, early symptoms in the myeloma patients - back pain, rib pain, chest pain, and recurrent chest infections – were not uncommon in control patients, and so were regarded as low risk. However, analysis showed that risk estimates changed if account were taken of those simple primary care blood tests that had been done.
The researchers analysed the primary care electronic data to classify recorded blood tests and their combinations as useful rule-in or rule-out tests for early myeloma. Their findings were published in the September 2018 issue of the British Journal of General Practice. The risk of myeloma was extremely low in patients with possible early symptoms who had a normal haemoglobin concentration (usually as part of a full blood count) and either a normal plasma viscosity or a normal erythrocyte sedimentation rate (ESR). Conversely, such patients with abnormalities of these tests had a raised risk of myeloma and would have benefitted from urgent blood and urine testing (protein electrophoresis).
The principal study investigator, Professor Willie Hamilton of the University of Exeter Medical School, told the Oxford University News Office: “Ordinarily a GP will see a patient with myeloma every five years – and early diagnosis matters. More timely treatment could significantly improve survival rates for this disease. We report a simple way a GP can check patients presenting symptoms such as back, rib and chest pain, or recurrent chest infections, and determine whether they have myeloma or not.”