METATSTATIC BONE DISEASE
Maxime Coles, MD, FICS, FRCS, FAANOS
Orthopedist and Traumatologist, 2011

Metastasis  means  spread  of  Cancer  to  any organ or tissue in the body. The cancerous cells break away from the primary tumor and invade the bloodstream or the lymphatic system. It is estimated that 1.2 million of new Cancer cases are discovered each year. Many theories tried to explain the formation of a Metastasis.

Sir James Paget  in 1889  was the first one to bring  a  ”Seed  and  Soil”  theory spreading  the cells  through  the  bloodstream  and  explaining the new formation of the same tumoral cells at a   different   location.   The   pathologist   James Ewing explained differently the colonization through the blood flow until Oscar Batson implicated the venous  system  of  the  spine to explain   the   spread   to   the   spine   from   the prostate   gland.   Others   think   that   a “Direct Invasion” theory is possible by erosion of a cuta- neous and cancerous lesion like a Melanoma or a   Squamous   cell   carcinoma eroding   deeply to the bone.

The skeletal system is considered the largest organ of the body and as such, it becomes a primer  target  for  metastasis.  Lesions metastizing distal to the knees and elbows are called acrometastasis and are often seen in the terminal phase.

Few  skeletal  lesions  require  surgical intervention unless they become enlarged or permeative. Radiation and Chemotherapy, Hormonal therapy …etc …often provide the first line of treatment for symptomatic relief but when they fail to help, Surgical treatment can be offered when feasible.

The goal of the Orthopedic Surgeon in treating metastatic lesions is to alleviate pain, improve function and ambulation rendering easier medical and nursing care as well as improving the  Psychological  well  being.  If  surgical treatment is contemplated, it must envision a post operative patient with immediate weight bearing. One should avoid any risky procedures. 50% of all metastatic lesions derive from Carcinomas (Breast, Lungs, Prostate), Lymphoma, Myeloma followed by kidney, thyroid, Genito-Urinary and Gastro-Instestinal tumors. The most common symptom of a metastasis   is   a   localized   pain   awaking   the patient  at  night,  impairing his ability  to  bear weight  on  the  extremity  but if  the  spine  is involved, often radicular or myelopatic symp- toms will be present.

The type of metastasis will dictate the kind of treatment.  Often  diffused  metastasis  to  the spine will pose a challenge to the spine surgeon necessitating a combination of debulking Intra lesional  excision  with  spinal  instrumentation to relieve  radicular  symptoms.  The  lesions  of the long bone are common and often require intramedullary fixation   supplemented   by   Ce- ment Polymethacrylate after resection or cure- tage of the lesion, Prosthesis and even Am- putation.

 

REFERENCES

1- Martin Malawer, Treatment of metastatic Bone
Disease, Chapter 11, 2001: pp215-230

2-NCCN Clinical Practice Guidelines in Oncology, Bone Cancer, www.nccn.org

3-Jemal A, Siegel R, Ward E et AL, Cancer Statistics,
2008. CA Cancer J Clin, 2008 ;(2):71-96

4- Rougraff RK, Kneisl JS, Simon MA., Skeletal Metastases of unknown origin. A prospective study of a diagnostic strategy. J Bone Joint Surg Am
1993;75(9):1276-1281

Info CHIR, M. Coles, No 2, p. 7, 2011

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