Bone and soft tissue sarcoma – diagnosis, current management and the future

Authors:

Details:

1. Bone and Soft Tissue Sarcoma Unit, Royal Prince Alfred Hospital, New South Wales.
2. University of Sydney and Sydney Cancer Centre, Royal Prince Alfred Hospital, New South Wales.


In introducing a forum on bone and soft tissue sarcoma, there are difficulties in view of the wide range of tumours involved and their relative rarity. In New South Wales, soft tissue sarcomas account for 0.5% of new cancer notifications per year, and bone sarcomas for 0.2%. There are over 70 sub-types of sarcoma, all with different behaviour, incidence, and age incidence. Although sarcoma is rare in adulthood, it forms one of the large peaks of malignant disease in children. It is, however, an area where there has been tremendous improvement in outcomes over the last 30 years. We are on the threshold of a molecular biological revolution which is likely to change the diagnosis and management of sarcoma profoundly.

Diagnosis

Many sarcomas, unfortunately, present late and in some cases up to 15% of cases will have metastatic disease at the time of presentation. Most present with either a mass or pain or both and radiological assessment is the most common initial investigation. In their article Soper, Brown and Schatz demonstrate a change towards specific imaging, with an emphasis on MRI, CT and PET scans, and where available, these three modalities produce the best information to guide biopsy and establish the extent of disease.1

In sarcoma, biopsy has proven to be a crucial stage due to the risk of error, as demonstrated by the results of an audit done by Stalley. 2 Histology for sarcoma relies extensively on the histological structure, meaning that on many occasions fine needle aspiration and cytology are inadequate or provide misleading information for diagnosis. Adequate tissue specimens are mandatory, particularly in view of the wide use of immunoperoxidase stains and cytogenetics for diagnosis.

With sarcomas so frequently affecting the limbs, it is important that biopsy procedures not compromise subsequent limb salvage opportunities. For this reason, it is recommended that, where possible, biopsy should be undertaken in the unit that is likely to be doing the limb salvage surgery.

Current therapeutic options

The mainstay for the management of sarcoma in 2010 remains the trilogy of surgery, chemotherapy and radiotherapy. Not all sarcomas lend themselves to all three modalities. For example, chondrosarcoma is predominantly a surgical disease.

Paediatric sarcomas, such as rhabdomyosarcoma and Ewing sarcoma, are responsive primarily to chemotherapy regimes, therefore surgery and radiotherapy must be regarded as adjuvant treatment modalities. The survivorship of children with Ewing sarcoma in the last 30 years has changed from 15% to 70%, mainly due to the advent of new and better chemotherapy regimes, and a more profound understanding of how to apply those regimes. The articles on Ewing sarcoma by Padhye and McCowage,3 and Rhabdomyosarcoma by HarilalChawla, Atern, Karpelowsky and McCowage,4 illustrate the significant change that has occurred in recent times in the management of both of these tumours.

The role for chemotherapy in all sarcomas remains hotly debated. While we have some evidence of improvement in outcomes for tumours such as synovial sarcoma, for many soft tissue sarcomas there is little evidence of overall increased survival.

Radiation therapy clearly has a major role to play in both primary care and palliative management of sarcoma. As outlined in the article by Hong,5 there are multiple modes of radiotherapy delivery available and the sequencing of that delivery is highly critical.

Limb sparing surgery in sarcoma is often the patient’s major episode of treatment and comprises a wide range of surgical options. The tumour surgeon must tailor the chosen procedure carefully as many of these patients, if the disease is cured, will have decades of life remaining. Limb salvage procedures must, therefore, be able to stand the test of time to avoid multiple repeat surgeries.
As outlined by Steadman,6 functional outcomes of amputation versus limb salvage demonstrate significant patient preference for limb salvage, where possible, and biological reconstruction appears to have greater longevity without reoperation.

The single most important principle in limb salvage surgery however, remains the clearance of disease with adequate margins. In his article, Choong demonstrates the established fact that despite the cost of many prostheses, limb salvage surgery, with time, is a less significant cost impost on the community than is amputation.7

As many patients present or develop pulmonary metastases in this area, the somewhat controversial role of pulmonary metastatectomy is discussed by Dear and Tattersall,8 and the indications for this treatment which, although may have very low cure rates, appears to have significant and appropriate indications.

The future

The two papers on the importance of molecular biology and new drug management in sarcoma by Thomas,9 and Moore and Desai,10 clearly demonstrate the exciting future for progress in sarcoma management. Molecular biology is demonstrating not only a more accurate method of categorising these difficult tumours, but is also demonstrating pathways for new therapeutic interventions.
Our understanding of this disease must be at a molecular level for progress to occur, and the complex understanding of the modes of action of targeting agents available to us will be a future management focus for these conditions.

References

1. Soper J, Schatz J, Brown W. Radiology of Bone and Soft Tissue Sarcoma Cancer Forum. 2010;34(3):126-130.
2. Stalley PD, Coggins K, Cato J. Biopsy in bone and soft tissue sarcoma: pitfalls. Cancer Forum. 2010;34(3):164-169.
3. Padhye B, McCowage G. Chemotherapy regimens in newly diagnosed and recurrent Ewing’s sarcoma in children and young adults. Cancer Forum. 2010;34(3):131-137.
4. HarilalChawla B, Verity Ahern V, Karpelowsky J, McCowage GB. Rhabdomyosarcoma: Considerations In Achieving Local Control. Cancer Forum. 2010;34(3):137-141.
5. Hong A. Role of radiation therapy in the management of soft tissue sarcoma. Cancer Forum. 2010;34(3):142-144.
6. Steadman P. Functional outcomes in limb salvage surgery for sarcoma. Cancer Forum. 2010;34(3):169-171.
7. Choong PFM. Principles of limb sparing surgery in bone and soft tissue sarcoma. Cancer Forum. 2010;34(3):145-148.
8. Dear RF, Tattersall MHN. Role of pulmonary metastasectomy in osteosarcoma and soft tissue sarcoma. Cancer Forum. 2010;34(3):149-153.
9. Thomas DM. Importance of molecular genetics of sarcomas. Cancer Forum. 2010;34(3):154-156.
10. Moore M, Desai J.New Drugs in the Management of Sarcoma. Cancer Forum. 2010;34(3):157-163.

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