The combination of two blood tests routinely ordered by general practitioners could speed the diagnosis of myeloma, according to a new study.
The research, “Early detection of multiple myeloma in primary care using blood tests: a case–control study in primary care,” was published in the British Journal of General Practice.
Myeloma may involve various symptoms, such as kidney failure, bone pain, fatigue from anemia, or headache from plasma hyper-viscosity (increased thickness of the blood).
Of all common cancers, myeloma has the longest interval from initial manifestation of symptoms to diagnosis. A large number of patients are diagnosed only after seeking emergency care, which is linked to to shorter survival.
Patients with myeloma also have the most consultations in primary care before referral to a specialist. According to the study authors, this long diagnostic process likely represents the non-specific nature of myeloma symptoms.
To meet the U.K.’s threshold for referral, myeloma symptoms need to be combined with abnormal blood results, including complete blood count, calcium, and inflammatory markers.
Although the inflammatory markers C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and plasma viscosity (PV) have been used together to diagnose myeloma, they have not been addressed individually.
In a collaboration between the U.K.’s University of Oxford, the University of Exeter, and Chiddenbrook Surgery, researchers intended to assess which inflammatory marker is best for initial assessment of myeloma by general practitioners, identify blood tests to rule out this cancer type, and differentiate early and late features of the disease.
The scientists analyzed symptom prevalence and blood tests up to five years before diagnosis in 2,703 myeloma patients and 12,157 healthy participants used as controls. Eligible patients were older than 40 years and had received a myeloma diagnosis between January 2000 and December 2009.
Results showed that PV and ESR are better for diagnosing myeloma compared to CRP, as the abnormal values of both of these markers were found in significantly more patients than controls. PV and ESR also were better for ruling out the condition.
As for noninflammatory markers, hemoglobin (the protein that carries oxygen throughout the body) performed much better to rule out this disorder than calcium and creatinine, both of which are found in increased levels in myeloma patients.
“A combination of a normal ESR or PV and normal hemoglobin is a simple rule-out approach for patients currently being tested in primary care,” the researchers wrote.
“If abnormalities are detected in this test, it should lead to urgent urine protein tests which can help speed up diagnosis,” Constantinos Koshiaris, the study’s lead author, said in a press release.
Willie Hamilton, the study’s senior author, commented: “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.”
Hamilton also noted that “more timely treatment could significantly improve survival rates for this disease.”
The authors also suggest the possibility of integrating a system in the electronic health record to alert clinicians to relevant symptoms or changes in blood parameters related to myeloma.
The study also showed that, in myeloma patients, hemoglobin levels started to decrease nearly three years before diagnosis, and that the mean hemoglobin value met the World Health Organization’s criteria for anemia throughout the final 24 months in men, and final 15 months in women. White blood cell and platelet counts remained within the normal range at all time intervals.
Also, calcium and creatinine levels increased rapidly in the last three to six months before diagnosis, while ESR and PV started to rise approximately two years before diagnosis. CRP showed no difference between patients and controls.
The data further revealed that symptoms such as back pain, rib pain, chest pain, chest infections, and nosebleed became more frequent in patients than in controls at nearly two years before diagnosis. Symptoms suggestive of advanced disease, including weight loss, fractures, and nausea were more common up to one year before diagnosis, particularly in the last three months.