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Physician use of red flags to screen for cancer in patients with new back pain

Henschke N, Maher CG, Ostelo RWJG, de Vet HCW, Macaskill P, Irwig L
Published Online: 
28 February 2013

This review describes the understanding of a common practice for checking for spinal injuries when patients come to a family practice doctor, back pain clinic or emergency room with new back pain.  Doctors usually ask a few questions and examine the back to check for the possibility of a spinal tumor.  The reason for this check for tumors is that the treatment is different for common back pain and tumors.  Tumors are usually diagnosed with an x-ray, magnetic resonance imaging (MRI) or computed tomography (CT), then treated with surgery and/or chemotherapy. Common back pain is treated with exercise, spinal manipulation, and pain relievers; x-rays, CT and MRI scans are not useful for diagnosis.  Tumors are rare, being the cause of back pain in approximately 1% of new back pain visits to family doctors.  Only about 10% of these cancers are new cases; 90% are recurrences of cancers from other parts of the body (metastases).

Six family practice studies including over 6,600 back pain patients found 21 tumors (0.3%).  One study on back pain diagnosed in an emergency room and one on back pain in a spine clinic included 482 and 257 patients.  The family practice studies described 15 different questions and physical exam tests that have been used to screen for spinal tumors.  Most of the 15 were not accurate.  A previous history of cancer is a very useful indicator.  Other facts that may indicate cancer are age greater than 50, no prior history of back pain, and failure to improve after one month.  These are most likely useful when combined, or with other indicators such as a history of cancer.  By themselves, these three questions would result in over-testing of patients without cancer.

The worst effects of low quality red flag screening are overtreatment and undertreatment.  If the tests are not accurate, patients without a tumor may get an x-ray, MRI, bone scan or CT scan that they don’t need—unnecessary exposure to x-rays, extra worry for the patient and extra cost.  At the other extreme (and much less common), it might be possible to miss a real tumor, and cause the patient to have extra time without the best treatment.

Most of the studies were of low or moderate quality and did not use an MRI, the most accurate imaging test, to confirm the presence or absence of a tumor, so more research is needed to identify the best combination of questions and examination methods.