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Tags: Orthopaedic surgery, Oncology
Primary bone sarcoma
Primary bone sarcoma (PBS) is a group of cancers derived from primitive mesenchymal cells.
Pre-op
Major questions:
- what the tumour is,
- where and how large it is,
- where else it has spread,
- what the effects of neoadjuvant oncological intervention have been
- what the surgical plan is
The most common PBS are osteosarcoma, chondrosarcoma, Ewing sarcoma and chordoma
Osteosarcoma has a bimodal distribution with an increasing incidence in those aged >60 yrs old
Chordoma is a rare and slow growing but locally aggressive PBS arising from the remnants of the notochord. It is mainly located in the sacrum and skull base and usually requires complex surgery such as sacrectomy and vertebrectomy
Considerations
High-flow vascular characteristics of the tumour may require preoperative embolisation
The presence of intrapelvic mass lesions, venous compression or pathological fractures requires assessment and discussion of the risk of thromboembolism
Resection of a craniofacial tumour requires diligent planning of airway management
large extraosseous components increase the complexity and duration of surgical resection.
Primary bone sarcoma mainly metastasises to the lung and bone
Chemotherapy
Common chemotherapeutic drugs used in osteosarcoma are
- methotrexate,
- cisplatin
- doxorubicin
those used in Ewing sarcoma include - vincristine,
- doxorubicin,
- cyclophosphamide,
- etoposide
- ifosfamide
Bone marrow suppression
Typically, a 2-week period allows for the recovery of chemotherapy-induced pancytopenia
full blood count should be assessed within 24 h before surgery as changes can be rapid.
Desirable features include a recovering trend of blood counts, neutrophil count >1.0×10^9/L if limb reconstruction is planned and the platelet count reaching a concentration adequate to support functional coagulation and safe regional anaesthesia
Renal dysfunction
a/w alkylating chemotherapy agents
- cisplatin,
- cyclophosphamide
- ifosfamide
unpredictable and irreversible
Caution is needed when assessing creatinine as concentrations may be low in patients with poor nutrition.
Immunotherapy
not standard
pembrolizumab is recommended for PBS with specific genetic markers in osteosarcoma, Ewing sarcoma, chondrosarcoma and chordoma in the USA. This necessitates multidisciplinary discussion to ensure that the timing of surgery mitigates the presence of systemic toxicity such as haematological toxicity, hepatitis, myopericarditis and pneumonitis
Intra-op
positioning - risk of neuropathy
In vitro experiments indicate that inhalational anaesthetic agents can promote immunosuppression whereas propofol may support natural killer cell function, thereby preserving any antitumour immunity
→ no definite conclusion
Patients undergoing complex sarcoma surgery are at risk of developing CPSP
A systematic review concluded that regional anaesthesia did not confer any benefit in tumour recurrence for patients who underwent primary resection of malignant tumours, but a recent study suggests i.v. lidocaine may exert a protective effect on cancer recurrence; this is not confirmed and is being investigated further
Current evidence shows contradictory conclusions on the effect of opioids on cancer development and metastasis
Patient blood management
three key tenets:
- identifying and managing anaemia before surgery;
- minimising perioperative blood loss;
- establishing transfusion targets to enhance tolerance of postoperative anaemia
topical fibrin sealants serve as an effective haemostat
The National Institute for Health and Care Excellence recommends the use of TXA when anticipated blood loss exceeds 500 ml and in complex cases such as pelvic surgeries.
Intraoperative cell salvage with a leukocyte depletion filter to remove malignant cells offers a technique to reduce allogenic blood transfusion, thereby mitigating the associated immune modulation and systemic inflammatory response
The presence of foreign antigens in the recipients of allogenic transfusion can induce the downregulation of immune responses, referred to as transfusion-related immune modulation, via the suppression of cytotoxic and natural killer cell activity. Outcome studies have highlighted the theoretical risk of tumour dissemination, but no conclusive evidence has emerged to suggest that it influences tumour recurrence, metastasis or prognosis
Post-op
Orthopaedic surgery is associated with a near three-fold increase in the risk for developing moderate to severe CPSP
Recent work has not supported an association between the short-term use of non-steroidal anti-inflammatory drugs (NSAIDs) and delayed bone healing
Tunnelling and removal of the catheters within the first 72 h of insertion should be considered to minimise the risk of infection in immunocompromised patients where daily inspection is mandatory.
There is a high incidence of venous thromboembolism after surgery for PBS that may be almost six-fold higher compared with primary soft tissue sarcoma
Musculoskeletal tumour, chemotherapy, major surgery and reduced mobility are independent risk factors for venous thromboembolism