Orthopaedic oncology

Question 1

What is a tumour?

Answer 1

• is a mass of tissue formed as a result of abnormal,excessive and inappropriate proliferation of cells, the growth of which continues idefinitely regardless of the mechanism that control normal cellular proliferation

Question 2

Tumours can be divided into?

Answer 2

• Benign- remain localised single masses
• malignant tunours- invade surrounding tissues

Question 3

What is important to check on a history of possible tumour?

Answer 3

• Pre-exisiting malignancy
• previous radiotherapy tx
• smoking
• peristent pain ( esp night)
• swelling
• night sweats
• weight loss
• altered sensation

Question 4

What tumours give rise to mets in bone?

Answer 4

• Breast
• Bronchus
• Prostate
• Kidney
• Thyroid
• Melanoma

most osteolytic except Prostate which is sclerotic

Question 5

What investigations are included is a neoplasia is suspected?

Answer 5

• FBC
• CRP/ESR
• Serum electrophoresis
  
  • Multiple myeloma ( bence jone- proteins urine)
• U& E, LFT’s
  
  • basline line but also elevated alk phosphatase in osteosarcoma.prostae specific antigen
• Plain xrays
• MRI
• CT- lesion and chest/abdo/pelvis for staging
• Tissue biopsy and histological analysis
• Bone scan- to detect skip lesions- ewing’s sarcoma

Question 6

What do benign lesion show on plain xrays?

Answer 6

• Bone reaction at the margin -> a well demarcated appearance with a narrow zone of transmission

Question 7

What do maligant lesion show on plain xrays?

Answer 7

• due to rapid growth they allow little bone forming reponse to develop.
• these lesions are poorly demarcated , permeative appearance with a wide zone of transmission
• osteosarcomas may elevate periosteum so quickly that bone deposition is allowed only at margin = Codman’s triangle
• Some attempt at bone formation by the periosteum overlying the lesion may -> streaks of calcification = sunray spiculations
• more agressive lesions from within the medulla->cortical resorption= endosteal scalloping

Question 8

Can do you describe common locations of certain tumours?

Answer 8

Question 9

Describe the prinicples of tissue biopsy?

Answer 9

• Provide a representative sample
  
  • for benign/malignant
  • to determine cell line
  • to grade lesion
• Not to compromise future surgery
• Timing
  
  • ​to do after investigation unless dx known
• Open vs closed
  
  • open preferred
    
    • adv:more tissue, low sampling error
    • dis:larger field to excise later,higher local complx- infection
  • needle biosy: less tissue to excise later/less expensive
    
    • dis: accuracy 70-88% cf open 95%
• Performed by treating surgeon at treating centre
  
  • ​complx rate x5-12 when preformed by other surgeon, 20% tx compromised by biopsy

Question 10

Describe the biopsy technique?

Answer 10

1. Preop
   
   • tumour staging
   • MSK team review
   • treating surgeon does biopsy
   • pathologist available for FF samples
   • no tourniquet
   • no antibiotics - infection always in DDx
2. Operative
   
   • approach
     
     • plan w future op in mind
     • all aspects of biopsy tract must be excised
     • incision incorop into definitive surgery
     • incision longitudinal, no tissue undermining
     • only enter one compartment/ trans muscular
     • don’t expose NV structures
     • meticulous haemostasis
   • biopsy
     
     • round cortical windows- reduce stress risers
     • swab taken for MCNS
     • tissue for FF section/ histology
     • no closure until DW pathologist on phone
     • esure they have enought to make definitive dx/stage etc
   • closure
     
     • ​plug bone with PMMA/minimise tumour spread
     • achieve haemostasis
     • closure in layers
     • drain exit site in line with incision & thru wound
     • subcuticular suture to skin
     • firm dressing
     • immobilise
3. Post operative
   
   • ​​​very careful post op path fx changes outcome
   • team approach on review of results for best outcome and future tx

Question 11

Can you describe the different factors invovled in the Enneking staging of tumours?

Answer 11

• Grade
  
  • G1
    
    • low grade
    • low risk of mets
    • well differentiated
    • few mitotic figures
    • moderate cytological atypia
  • G2
    
    • high grade
    • higher incidence of mets
    • poorly differentiated
    • high mitotic rate
    • high cell /matrix ratio
    • necrosis
    • microvascular invasion
• Site
  
  • T1 =Intracompartmental
  • T2- extracompartmental
• Mets
  
  • ​Mo= No mets
  • M1= mets present

Question 12

Can you decribe the different enneking staging of tumours?

Answer 12

• Stage 1A
  
  • low grade G1
  • T1 - intracompartmental
  • Mo
• Stage 1B
  
  • Low grade G1
  • T2- extracompartmental
  • Mo
• Stage 2A
  
  • High grade G2
  • T1
  • Mo
• Stage 2B
  
  • High grade G2
  • T2
  • Mo
• Stage 3
  
  • M1
  • Any grade and site

Question 13

What are the different options for tumour excision?

Answer 13

• Intralesional
  
  • path of excision passes thru the pseudo-capsule and directly thru lesion
  • entire operative field is considered potentially contaminated
• Marginal
  
  • entire lesion is excised as one peice
  • plane of dissection in pseudo-capsule
• Wide
  
  • lesion is removed with pseudocapsule and cuff of normal tissue
  • aka en bloc resection
• ​Radical ( extracompartmental)
  
  • ​entire lesion and its structure of origin are removed
  • plane of dissection is outside the limiting fascia or bone

Question 14

what is the aim of treatment of tumour?

Answer 14

• Irradicate tumour but
• Preserve function

Question 15

What are the indictions for ampuation?

Answer 15

• Pts in whom perivascular or neurological invasion renders resection of the tumour impossible without sacrifing distal function or viability
• pt in whom tumour excision including biopsy tracts cannot be achieved without extensive excision of muscle
• Pathological fx where there has been significant contamination by the tumour

Question 16

What are the options for limb salvage?

Answer 16

• Endoprosthesis
  
  • massive endoprosthetic replacement
    
    • custom made
    • growing endoprosthetic
• Autograft
  
  • when only resection of diaphsyeal bone is required may use strut graft ( fibula)
  • excision , irradiation then implantation ( pelvic ring)
• Allograft
  
  • large bulk of bone may be non viable
  • risk of disease transmission
  • availability of cadervic bone

Question 17

What condition uses adjuvant and neodajuvant chemo?

Answer 17

• OSteosarcoma
• Ewing’s
• neoadjuvant chemo post surgical ressection has demonstrated to improev survivorship

Question 18

What condition uses radiotherapy?

Answer 18

• for primary and soft -tissue tumour resection where a histological marginal resection is demonstrated or where pt factors limit the surgical resection can be achieved.
• use for bone mets and pathological fx after stabilisation
• Osteosarcoma
• little effect with chondrosarcomas ( also no effect with chemo)