Osteosarcoma develops from the cells that form bone, accounting for 35% of all bone cancers. There is a preference for origination in the metaphyseal region of tubular long bones, with 42% occurring in the femur, 19% in the tibia, and 10% in the humerus. About 8% of all cases occur in the skull and jaw, and another 8% in the pelvis.

Complete radical surgical en bloc resection is the treatment of choice in localized osteosarcoma and about 80% of patients are able to have limb-salvage surgery.

The investigations include an x-ray, CT scan, bone scan, MRI or PET scan and a surgical biopsy. Bone biopsy is the only definitive method to determine whether a tumor is malignant or benign. The biopsy of suspected osteosarcoma should be performed by a qualified surgical/orthopaedic oncologist. An improperly performed biopsy may make it difficult to save the affected limb from amputation.

Patients with osteosarcoma are best managed by a medical oncologist and a surgical oncologist experienced in managing sarcomas. Current standard treatment is to use neoadjuvant chemotherapy (chemotherapy given before surgery) followed by surgical resection. With the advent of chemotherapy, limb preservation is now possible in over 80% of patients with localized osteosarcoma. The percentage of tumor cell necrosis (cell death) seen in the tumor after surgery gives an idea of the prognosis and also lets the oncologist know if the chemotherapy regime should be altered after surgery.

Case Summary:

A young boy of 17 years of age presented with pain and swelling of the left upper leg since 3months. He had undergone bone biopsy outside. Paraffin blocks reviewed in our Pathology Department reported as chondroblastic osteosarcoma. MRI of the left leg showed a well defined lobulated lesion in the metadiaphyseal region of the left upper tibia with abnormal marrow signal intensity in metaphysis and upper third of the diaphysis. Soft tissue involvement seen on anterolateral aspect with focal area of cortical breech in upper tibia ?due to biopsy. Knee joint is intact. No vascular involvement. Metastatic workup with CECT thorax and whole abdomen as well as bone scan revealed no distant metastases. Case was discussed in the tumour board and planned for neo-adjuvant platinum based chemotherapy followed by surgery.

He received 3cycles of chemotherapy with Inj. Cisplatin 160mg on D1 and Inj. Adriamycin 40mg on D1,2,3 from 13/11/2009 to 13/01/2010. Post chemo MRI (27/01/2010) showed persistent disease with no significant interval change with altered signal reaching just up to articular surface of medial condoyle of tibia. Repeat metastatic workup was normal. Case was discussed again in the tumour board and planned for surgical resection with reconstruction.

Radical resection of left proximal half of tibia with frozen section control for margin clearance + reconstruction of left knee joint and upper tibia with modular titanium total knee hinge prostheses + bone grafting + left medial gastrocnemius muscle rotation flap cover of the prostheses done under general anaesthesia on 05/02/2010. Final histopathology showed residual disease infiltrating overlying skeletal muscle. All margins were free of tumour. Post operatively patient recovered well with good functional outcome.

He has completed 3cycles of adjuvant chemotherapy. Follow up PET-CT scan done on 05/05/2010 showed no residual disease. He is now able walk without support and able to climb stairs.

Overview

Surgery is an integral part of treatment for patients with localized osteosarcoma as well as select patients with metastatic or recurrent osteosarcoma. Treatment of osteosarcoma without surgery results in significantly lower cure, tumor-free survival, and overall survival rates. Reconstructive surgery is also an important component of the overall management of osteosarcoma, requiring the skills of a surgical oncologist and an orthopaedic surgeon.

Because osteosarcoma is a relatively rare cancer, treatment should be conducted in specialized cancer centres. A study of 202 patients treated for osteosarcoma showed that 49% of these patients lived 5 years or more. This study compared limb-sparing and survival rates from 3 different centres affiliated with the European Osteosarcoma Intergroup. Although patients who had undergone limb-sparing surgery did experience local recurrence of their cancer, 31% of these were cured with subsequent surgery.

Reconstructive Surgery

Limbs may be reconstructed after surgical removal of the primary osteosarcoma. There are a number of different reconstructive surgery procedures including bone grafts, rotationplasty, and endoprosthetics. Selection of treatment depends on the location and extent of the bone removed and the age of the patient, since some treatments are limited in young patients who are still growing.

Endoprostheses utilize artificial material to fill in for surgically removed bone, or functional joints to replace the amputated joint. Two studies conducted at UCLA have reported effective and durable results with this technique. In the first study, reconstruction with endoprostheses was used in 78 of 100 patients treated for localized osteosarcoma. Excellent results were reported in reconstruction of the upper leg near the knee. In another study, 151 patients received endoprostheses for primary tumors involving bone. Modification of the prosthesis was necessary in 21 patients. Mechanical failure was the primary complication, which occurred in 15.9% of patients. However, local problems were usually managed without amputation and the prostheses proved durable, with 91% of patients surviving three years and 83% surviving five years.