Dr Gerard Crotty
Consultant Haematologist, Midland Regional Hospital, Tullamore
It is difficult to diagnose myeloma early as symptoms are non-specific. Blood tests and imaging can lead to early diagnosis.
Diagnosis of multiple myeloma is often delayed, as is the case with many rare cancers. The diagnosis needs to be made more quickly in primary care.
However, myeloma symptoms are nonspecific, which makes it hard for GPs to suspect the disease. The most common symptom is back pain, but the frequency of this symptom in people attending their GP makes early diagnosis difficult.
A rare disease
Myeloma incidence in Ireland is six per 100,000 per year1. Thus, a GP with 2,000 patients will have one new case in just over eight years.
The average GP will diagnose only two or three cases in a professional lifetime and may not have confidence in making the diagnosis. So, what is needed is that the appropriate advice is sought or referral made when features suggestive myeloma.
The incidence of myeloma is higher in males and in black people. Older age is also a risk factor – as for many malignancies. However, none of these risk groups are sufficiently at risk for screening to help.
Obesity is the main modifiable risk factor – maintaining a healthy weight has many benefits but only has a minor effect of the risk of myeloma.
Most myeloma patients have a prodromal phase of monoclonal gammopathy of undetermined significance (MGUS). However, population screening for MGUS is not of benefit and may harm quality of life.
Follow up of patients with known MGUS is standard practice and picks up a small number of myeloma cases early, before complications such as renal failure or pathological fractures occur.
Blood should be tested if there is suspicion of myeloma
Investigation of symptoms is the mainstay of early diagnosis. Blood tests should be requested where myeloma could be a cause of the presentation.
Blood count, creatinine and calcium as well as ESR or plasma viscosity are appropriate first line tests. A normal haemoglobin and ESR help exclude myeloma2.
Where symptoms suggest myeloma, serum electrophoresis and, in selected cases, urine electrophoresis and serum free light chain assay are important.
But these tests should not be used indiscriminately and appropriate clinical details should be provided, to aid the laboratory scientific and medical staff in providing advice. Often a phone call to a haematologist can clarify interpretation or results and help prioritise referrals.
MRI scans for bone disease can signify myeloma
Investigation of back pain (with ‘red flags’) by imaging – such as MRI – is an important route to diagnosis. Myeloma most commonly presents with bone disease, usually in the axial skeleton, but tumours anywhere on imaging need prompt referral for tissue diagnosis.
Most myeloma bone lesions are purely lytic and the finding of lytic lesions should always warrant consideration of myeloma and blood and urine tests.
Putting it together
Abnormal results, such as anaemia and renal impairment have many other causes and recognition of myeloma often comes from a combination of symptoms and laboratory abnormalities, for example, anaemia with back pain.
Vigilance for this disease will often allow pattern recognition suspicion of a diagnosis, with confirmation by haematologist.
1.National Cancer Registry of Ireland (ncri.ie) 2.Early detection of multiple myeloma in primary care using blood tests: a case–control study in primary care. Koshiaris C et al, British Journal of General Practice 2018; 68 (674): e586-e593