Metastatic cancer mimicking mechanical low back pain: a case report

The purpose of this report is to describe the clinical course of a patient referred to physiotherapy (PT) for the treatment of low back pain who was subsequently diagnosed with metastatic non-small cell carcinoma of the lung.

A 48-year old woman was referred to PT for the evaluation and treatment of an insidious onset of low back pain of 2 month duration. The patient did not have a history of cancer, recent weight changes, or general health concerns. The patient's history and physical examination were consistent with a mechanical neuromusculoskeletal dysfunction and no red flag findings were present that warranted immediate medical referral.

Short-term symptomatic improvements were achieved using the treatment-based classification approach. However, despite five PT sessions over the course of 5 weeks, the patient did not experience long-term symptomatic improvement. On the sixth session, the patient reported a 2-day history of left hand weakness and headaches. This prompted the physiotherapist to refer the patient to the emergency department where she was diagnosed with lung cancer.

Differential diagnosis is a key component of PT practice. The ability to reproduce symptoms or achieve short-term symptomatic gains is not sufficient to rule out sinister pathology. This case demonstrates how extra caution should be taken in patients who are smokers with thoracolumbar region pain of unknown origin. The need for caution is magnified when one can achieve no more than short-term improvements in the patient's symptoms.