Metastatic
tumours
A pathological fracture through a metastatic tumour may be the first
clue that a patient has malignant disease. Indeed, the primary may never be
found. In other cases metastatic bone disease occurs some time after treatment
of the primary tumour. The commonest source of metastases in bone is tumours of
the breast, the prostate and the kidney. In patients who are suspected of having
metastases, a radioisotope bone scan may show up lesions which are nor yet
symptomatic, and which may not even be visible on X-ray (Fig.
25.6).
The
management of metastases is excision, where these are isolated and relatively
slow growing. In the majority of cases radiotherapy and/or chemotherapy can be
used to slow the rare of growth of the lesion. If more than 50 per cent of the
cortex is eroded over more than 2 cm then it is considered that the long bones
are liable to imminent pathological fracture. Under these circumstances it is
best to stabilise the bone before it breaks. In the femur, the tibia or the
humerus, a prophylactic intramedullary nail can be used to support the bone.
Even where a fracture has already occurred, stabilisation and radiotherapy will
relieve the patient’s pain, allow them to remain mobile and may even allow the
fracture to heal.
Before
embarking on stabilisation of a metastatic lesion, it is always worth taking an
X-ray of the whole bone and of the
These are very rare indeed. The commonest of this rare group is the
osteosarcoma. These tumours have very variable histology and occur either in
adolescents or in the elderly secondary to Pager’s disease. The tumour is
metaphyseal
Imaging
Characteristically, there is periosteal lifting (Codman’s triangle)
and ‘sun-ray’ spicules of new bone within the tumour. Magnetic resonance
imaging (MRI) and computerised tomography (CT) scan may be helpful in
determining the true extent of the tumour within the medulla (Fig.
25.7).
Treatment
The choice of treatment depends on the histological grading of the tumour, the age of the patient, the presence or absence of secondaries and the
wishes of the patient.
If
there is no evidence of secondaries, and it is technically possible, an
amputation may be the treatment of choice with chemotherapy used to destroy
micrometastases. Alternatively, radiotherapy and chemotherapy to shrink the
lesion followed by a massive joint replacement may carry a higher risk of
recurrence but may be cosmetically and functionally much more acceptable. If
massive joint replacements are to be used in growing children, then designs need
to be used which allow for lengthening of the limb as the child grows. Massive
allografts using bones and joints from cadaver donors have limited long-term
success, and have problems with rejection and the possibility of transmission of
infection.
prognosis
Survival is dependent on the histological grading and the degree of
spread, but in cure rates of around 50 per cent can be achieved.
Chondrosarcoma
This tumour commonly occurs in the pelvis, ribs or proximal long bones
in middle-aged people. The tumour is lyric with ill-defined boundaries and has
speckled calcification within its substance (Fig. 25.8). The grade of
malignancy is very variable and is closely linked to the prognosis. Low-grade
tumours have a survival rate of 75 per cent at 5 years, while
high-grade tumours have a survival rate of less than 10 per cent over the same
period.
Fibrosarcoma
These tumours occur
most commonly in the metaphysis or diaphysis of the tibia or femur, but may also
arise in soft
Synovial
sarcoma
This is a highly malignant tumour which metastasises through the blood
supply, bloodstream and lymphatics. Five-year survival rare is low whatever
treatment is attempted.
Ewing’s
tumour