BONE AND SOFT TISSUE SARCOMA

Musculoskeletal sarcomas are relatively uncommon neoplasms. This leads to less exposure of these tumors to most clinicians leading to under- diagnosis, missed diagnosis, incomplete staging workups and hence inadequate treatment. There is strong need to create awareness about sarcoma management. With the recent advances in imaging, adjuvant treatment and surgical techniques, not only the local control of the disease has gone better, but have also improved the survival of the patients.

The moment there is clinical and radiological suspicion of musculoskeletal sarcoma, it should be immediately referred to a hospital where there are qualified radiologist, pathologist and orthopaedic /surgical oncologists to diagnose and plan the management of these sarcomas.

SUSPICIOUS OF SARCOMA

a. SUSPICIOUS BONE SARCOMA: The commonest symptom of bone sarcoma is non-mechanical pain and palpable mass arising from bone, which needs plain radiograph in two planes. The presence of any of the following is suggestive but not diagnostic of bone sarcoma:
2. Bone destruction
3. New bone formation
4. Periosteal swelling
5. Soft tissue mass

With any of the above findings, it is must to consult an orthopaedic oncologist.

a. SUSPICIOUS SOFT TISSUE SARCOMA: Any soft tissue lump which is larger than 5cms and is deep to deep fascia should be regarded as soft tissue sarcoma unless proved otherwise. These lumps are increasing in size and may be painful. Soft tissue sarcomas of pelvis are often missed clinically on examination leading to delayed diagnosis and large size of these tumors.

BIOPSY:

All patients with suspected sarcoma must undergo complete local imaging (as per guidelines) before any biopsy is planned e.g. plain radiographs, MRI of the site and/or CT scan. Ideally biopsy should be done at a centre where definitive treatment is also possible, otherwise the clinician must get a consult from orthopaedic or surgical oncologist before deciding site and technique of biopsy. Core needle biopsy is the gold standard for most of cases. Additional studies like immunohistochemistry, cytogenetic and molecular studies are desirable in some sarcomas e.g. Ewings sarcoma and soft tissue sarcoma. A poorly performed biopsy may not only fail to provide the correct diagnosis, but may lead to extensive subsequent surgery thus making the limb salvage surgery difficult and negative impact on overall survival of the patient.

Once the diagnosis of sarcoma has been made, it has to be treated at a multidisciplinary cancer centre.

STAGING WORK UP:

In osteogenic sarcoma and chondrosarcoma, non-contrast CT scan of chest and bone scan is required to rule out metastasis. In Ewing sarcoma, non- contrast CT scan of chest + bone scan + bone marrow aspiration & biopsy done bilaterally is required, however if possible FDG PET scan with breathhold CTscan is an alternative to all the above tests.

In Soft tissue sarcoma non-contrast CT scan of chest is must

TREATMENT:

Treatment plan is multidisciplinary as discussed in guidelines ahead.

SURGERY: Surgery has to be planned after adequate staging and planning with multidisciplinary team. The goal of surgery is adequate oncologic clearance. The decision of optimal surgical procedure is based on individual case to case basis depending on various factors (patient’s age, tumor site, size, extent and response to neoadjuvant treatment).

Amputation can be performed by a local surgeon for oncologic clearance based on level guided by sarcoma management team.
 
If limb salvage surgery has to be performed as per decision taken by multidisciplinary team, then type of reconstruction offered will depend upon risks and benefits of different options, experience and facilities available as well choice of patient & surgeon.

Resected specimen needs to be evaluated for adequacy of surgical margins (Quantitative and Qualitative margins) as well as percentage necrosis (when neoadjuvant chemotherapy has been given).

CHEMOTHERAPY: Multi agent chemotherapy is standard of care in osteosarcoma and Ewing sarcoma.

RADIOTHERAPY: Osteosarcoma and Chondrosarcoma being relatively radioresistant tumor, so limited role of radiotherapy. Radiotherapy has definite role in Ewings sarcoma and high grade soft tissue sarcoma.
SURVEILLANCE:

The risk assessment is based on tumor grade, tumor size and tumor site. High risk patients generally relapse within 2-3 years, while low risk may relapse later, though less likely. Although the use of MRI to detect local relapse and CT to scan for lung metastasis is likely to pick up recurrence earlier, it is yet to demonstrate that this is beneficial or cost effective compared with clinical assessment of the primary site and regular check X- rays.



( Courtesy: BST services, Tata Memorial Hospital, Mumbai )

DR.R.R. SAGGAR
Orthopaedic Oncology (Bone and soft tissue tumor surgeon)