Osteosarcoma: early diagnosis is the key to survival for patients

Posted: 03/07/2018

Sarcomas are rare cancers that develop in the muscles, bones, nerves, cartilage, tendons, blood vessels and fatty / fibrous tissues. Although there are more than 50 types of sarcoma, they can be grouped into two main kinds, soft tissue sarcomas and bone sarcomas.

Osteosarcoma is sometimes referred to as a primary bone cancer. It is extremely rare and makes up only 0.2% of all cancer diagnoses in this country, so less than 500 people in the UK each year. While the condition typically arises in adolescents, this is not always the case. Osteosarcoma can affect any bone in the body but is most commonly found in the legs (ie the femur or tibia bones). The cancer usually presents as an aching pain, which gradually becomes worse and can develop into a lump at the affected site. X-rays will typically show a lytic lesion, where the bone appears to have been eaten away, or new bone formation. Either of these findings should raise concern and prompt further investigations. In other words, an X-ray of the affected area will look abnormal. Once diagnosed, treatment of an osteosarcoma involves staging the cancer to look for any metastatic spread, and then treatment with chemotherapy, with or without surgery.

The prognosis for survival is related to whether or not there has been metastatic spread at the time of diagnosis and then the response of the osteosarcoma to chemotherapy. Survival rates are approximately 55% at five years, and if the patient survives those five years with a developing metastatic disease, there is around a 90-95% chance of being cured.

The clinical negligence team at Penningtons Manches has investigated a claim relating to a delayed diagnosis of osteosarcoma. The client presented at casualty where X-rays were taken which reportedly showed a simple avulsion fracture to the tibia; in fact they showed a clearly defined lytic lesion, which should have caused concern and led to further investigations. NHS trusts have a duty of care to ensure that all investigations carried out are reviewed by a medical practitioner of an appropriate competence in order to identify abnormalities. In some hospitals X-rays taken in the casualty department are reviewed by a consultant radiologist, but in others, as was the case for this client, the patient may be referred to a fracture clinic where an orthopaedic surgeon reviews the X-rays. Nevertheless, a consultant orthopaedic surgeon is still expected to review an X-ray properly and spot a clearly defined lytic process. A good standard of medical treatment would involve diagnosis of a lytic lesion, which is then investigated further by way of an MRI scan, which would be likely to show the lesion in the tibia, ie an abnormal result which would trigger a referral to a specialist sarcoma unit for further treatment, including chemotherapy, as soon as possible.

For this client, the hospital staff’s failure to recognise the lytic lesion in the tibia meant that an incorrect diagnosis of a simple avulsion fracture was made followed by a referral for physiotherapy, which was of no benefit and caused further pain. The misdiagnosis meant that the opportunity to make an early diagnosis of osteosarcoma and start chemotherapy treatment promptly was lost. The NHS trust in question carried out an internal investigation which concluded that a poor standard of care was given to the radiology reporting. There was a low level of awareness of bone and soft tissue sarcomas in both the fracture clinic and physiotherapy department. A standard operating procedure for the reviewing of X-rays in fracture clinics was recommended by the trust, as well as a better mechanism for patients to be referred back from physiotherapy if they did not improve.

Alison Johnson, an associate director in the Penningtons Manches clinical negligence team, says: “People can survive osteosarcoma and have a good prognosis, but the key is early diagnosis, when treatments can be most effective before the sarcoma has spread (metastasized) to other parts of the body. It is also vital that patients are referred to a specialist sarcoma team as soon as possible.”

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