Ewing’s Sarcoma

Ewing’s sarcoma

 Symptoms |Signs |Treatment

 

Ewing’s sarcoma is a round cell tumor, a component of the Ewing’s Sarcoma Family Of Tumours (EFTS).

What is the Incidence ?

• It is rare cancer
• But the second most common primary bone cancer.

  

What ages does it affect ?

• Seen in the age group of 5-20 years commonly.
• Adults are uncommonly affected.

What is the cause ?

• The etiology of Ewing’s sarcoma is evident as reciprocal translocation between chromosome 11 and 22 in 85 % of cases.
• EWSR1 and FLI1 fusion are identified in the majority of cases on Rt-PCR & FISH.
• Immunohistochemistry (IHC) identifies CD99, Fli-1 as confirmatory.

Which bones does it affect ?

• Long bones
• Pelvis
• Chest wall
• Spine, clavicle, hand and foot
• Extraosseous (Soft tissue) commonly seen in trunk and extremity

How is Ewing’s Sarcoma identified?

Ewing’s sarcoma | Symptoms | Signs | Treatment

• Symptoms
  • Pain (Night Pain, Rest Pain)
  • Swelling (Rapidly progressive)
  • Masquerades as infection of bone in some instances with purulent discharge, may have fever as main symptom
  • Pathological fracture due to trivial trauma
  • In advanced cases, loss of weight , appetite

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• Tests
  • Plain Radiograph
  • MRI with contrast
  • CT scan
  • Image guided biopsy
  • Whole body FDG PET CT scan
  • Blood tests-LDH, ALP, ESR, CBC
• Nearly 75 % of individuals present with a solitary primary tumor without any distant metastases.
• Around 10 % of patients present with microscopically detectable bone metastases.

What tests are done on biopsy tissue?

• Histopathological evaluation
• Cytogenetic analysis
• Immunohistochemistry
• Flow Cytometry

What are the treatment Options ?

• The treatment of Ewing’s sarcoma is by a multidisciplinary team similar to osteosarcoma.
• Chemotherapy (Various regimens are used, 2 weekly interval Dose intense regimen is preferable)
  • Preoperative
  • Evaluation of Chemotherapy response by Imaging & Evaluation of specimen
  • Postoperative
• Surgery: Limb salvage in 95% of cases.
• Type of Limb salvage surgery will be individualized.
• Rarely, amputation

• Radiotherapy: Effective is Ewing’s sarcoma.
• Often given as Post operative (Often based on size, operative margin)
• Rarely, as preoperative along with chemotherapy to shrink the tumour.
• Rarely, instead of surgery (Reserved for Non operable or High risk cases in pelvis, spine, sacrum and large size of primary tumor. Risk of recurrence is 10-20 %).

• High dose chemotherapy with stem cell rescue
• Targeted therapy, Immunotherapy

How is Limb Salvage possible in Ewing’s Sarcoma?

• Certain bones in our body are expendable and do not require any further reconstructive or salvage procedures like clavicle, rib, scapula, sternum, distal ulna and ilium.
• The cancer is removed En-Bloc with wide margins
• Reconstruction options include the same modalities as discussed in osteosarcoma which are individualized.
  • These are Bone Grafts (Autologous or Allogeneic) which can be segmental (intercalary) or osteoarticular aided with implants
  • Metallic Endoprosthesis (Megaprosthesis)
  • Allograft-Prosthesis Composite (APC)
  • Extracorporeal radiation and Re-implantation (ECRT)
  • Vascularized fibula construct
  • Allograft resurfacing.
  • In children and adolescents who have tumors involving growth plate and residual growth remaining, an APC or Expandable Endoprosthesis (invasive or non-invasive) are performed.
  • In individuals who have attained skeletal maturity, most common options are adult endoprosthesis and reconstruction using different modes of Bone grafts as outlined above.
  • In case of involvement of shaft or diaphysis of long bones and pelvis, the removed tumor bone can be irradiated and reimplanted or substituted with allograft.
  • Rehabilitation is provided according to the type of reconstruction.

What is the treatment for Metastatic disease?

• Most common site is Lung. Bone involvement is uncommon.
• A whole body fdg pet ct scan follows for staging.
• If an individual has distant metastases (lung most common), it can be surgically removed after removal of the primary tumor.
• If lung involvement is extensive then Radiotherapy to lung is provided
• Chemotherapy is necessary, but regimens of drugs may differ.

What are the rehabilitation steps involved post limb salvage?

• Rehabilitation post-surgery is dependent on the type of limb salvage.
• In case of bone graft reconstruction or APC, the involved limb is protected from bearing load or weight for a duration of 6 – 9 months to allow sufficient healing and bone graft incorporation.
• When endoprosthesis reconstruction is performed in pelvis and lower limbs, protected weight bearing and walking is allowed from the second postoperative day.

How often should I visit the doctor?

• The individual is followed up every 3 months for the first 2 years, followed by 6 months every 3 years (aggressive monitoring of the patient until 5 years).
• Overall survival of primary non metastatic Ewing’s sarcoma at presentation is 60 – 70 %.
• Distant metastases and local recurrence may necessitate change in chemotherapy protocol depending on the nature of event.
• Solitary metastasis and local recurrences require to be surgically removed.
• Survival of this specific category of individuals is 20-30 % at 5 years.
• Occurrence of multiple widespread metastases or multiple local recurrences increase morbidity and mortality risk.

Are there any prognostic factors for Ewing’s sarcoma?

• Stage of disease

Better prognosis is for primary tumor without metastasis

• Bone or Soft tissue involvement
• long bone involvement compared to pelvis and axial sites,
• small tumor size (less than 200 ml)
• children compared to adults
• lung metastases compared to bone metastasis
• response to initial chemotherapy surgery and radiotherapy
• Combination of Surgery and Radiotherapy
• LDH, Alkaline Phosphatase levels
• Gene changes
• Pathological Fracture
• In case of recurrence, the site and stage