Bone Metastasis Grand Round

Report
Orthopedic Surgery Grand Round
7th February 2013
Dr. J.W. Kinyanjui
Registrar Ward 6D
Outline
 Introduction
 Epidemiology
 Pathophysiology
 Clinical evaluation
 Management
Introduction
 Fracture through abnormal bone
 Minor trauma or during normal activity
 5th decade most prevalent
 Metastases 2nd most common cause of pathologic fractures
 F: breast and lungs – 80%
 M: prostate and lungs – 80%
 10% - no primary tumor found
Epidemiology – incidence at
autopsy
Primary Site
Breast
Lung
Prostate
Hodgkin’s
Kidney
Thyroid
Melanoma
Bladder
% metastasis to Bone
50-85
30-50
50-70
50-70
30-50
40
30-40
12-25
Pathophysiology
 Most spread is hematogenous
 Few tumors due to contiguous spread
 Most common osteolytic via osteoclast stimulation
 Prostate – commonly osteoblastic
 Breast – mixed
 Theories explaining predilection of bone for metastasis
Paget’s fertile soil hypothesis
 1889
 Sites of secondary growths are not a matter of chance
 Some organs provide a more fertile environment for the growth
of certain metastases
 Example: breast cancer to liver, Krukenberg tumor
 Prostate cancer to bone
 Hart and fielder later proved this using radioactive labelling
Ewing’s circulation theory
 1928
 Metastatic deposits dependent on route of blood and
lymph flow
 Organs though to be passive receptacles
 Organs with prominent venous systems have more
secondaries
 Baston plexus of spine responsible for prostate secondaries
Red marrow theory
 In descending order of frequency:
 Spine
 Pelvis
 Ribs
 Proximal appendicular skeleton
 Marrow sinusoids more susceptible to tumor cell
penetration
 Sudden change from arterioles to sinusoids favours
tumor cell entrapment
 Ewing’s and Paget’s theories not mutually exclusive
Molecular level
 Cells from primary enter blood vessels
 Attachment and penetration of basement membrane,
neovascularisation
 Type 1 collagen shown to be chemotactic to tumor cells
 RANK ligand produced by tumor cells stimulating osteoclast activity
 PTHrP produced by breast and lung cancer cells stimulates osteoclasts
 Prostate cancer cells produce BMPs, IGF1, TGFβ2 which stimulate
osteoblasts
Clinical evaluation: History
 Pain – most common, preceding fracture, night, constant,
dull, aggravated by activity
 Trauma – usually minimal for type of fracture
 Constitutional – anorexia, night sweats, weight loss, fatigue
 Previous cancer
 Carcinogen – smoking, radiation, occupational toxins
Factors suggesting pathologic
fracture
 Spontaneous fracture
 Minor trauma
 Pain at site preceeding fracture
 Multiple recent fractures
 Age > 45 yrs
 Prior history of malignancy
Associated problems
 Lowered Quality of life:
 Debilitating pain
 Immobility
 Neurologic deficits – spine mets
 Anaemia
 Hypercalcemia
Hypercalcemia
 Neurologic: headache, confusion, irritability, blurred vision
 Gastrointestinal: anorexia, nausea, vomiting, abdominal
pain, constipation, weight loss
 Musculoskeletal: fatigue, weakness, joint and bone pain,
unsteady gait
 Urinary: nocturia, polydypsia, polyuria, urinary tract
infections
Clinical evaluation: examination
 Local: mass, deformity, tenderness, contiguous
skeleton, neurologic exam
 Systemic: cachexia, pallor, lymphadenopathy, entire
skeletal system
 Primary: breast, thyroid, prostate, lung, pelvic
Clinical evaluation: Laboratory
 TBC – anaemia of chronic disease
 Calcium – elevated
 Alkaline phosphatase – elevated, non specific
 Tumor markers – PSA, CEA, CA125, TFTs
 N-telopeptide + C-telopeptide – markers of bone
destruction, determine extent of skeletal involvement,
assess response to bisphosphonates
Imaging: plain radiographs
 Enneking’s questions:
 Location: diaphysis, metaphysis, epiphysis, cortical or
medullary
 Effect: osteoblastic vs. osteolytic or mixed
 Reaction: sclerotic rim, periosteal reaction, codman
triangle
 Isolated avulsion of lesser trochanter – imminent femoral
neck fracture
Osteolytic, diaphyseal medullary,
periosteal reaction
Osteoblastic mets to bone
Codman triangle
Osteolytic lesion in lesser trochanter
Radiology: CT scans
 Most sensitive for detecting bone destruction
 Determines extent of cortical involvement
 Also used to search for primary lesion in pelvis,
abdomen or chest
Mixed lesion in lung mets
Radiology: MRI
 Most sensitive for assessment of the anatomic extent of
a lesion
 Most adequate for spinal metastases to determine
neurologic structure involvement
 Can determine extraosseous spread of a mass
Bone scanning
 Technetium-99m (99m Tc) bone scanning:
 Sensitive for detection of occult lesions
 Assessment of the biologic activity of lesions
 Identification of other sites
 Assessing response to therapy
Biopsy
 Indicated to rule out primary tumor of bone
 Immunohistochemistry can determine primary
 Biopsy at fracture site complicated by bleeding and callus
formation
 Needle vs incisional
 Oncological surgical principles adhered to
 Cultures to rule out infection
Impending pathologic fractures
 Prophylactic stabilisation before radiotherapy can be
performed for pain
 Radio and chemotherapy without stabilisation also an
option
 Decision to stabilise difficult
 Mirel’s criteria useful to determine which lesions at
high risk of fracture
Mirel’s criteria
VARIABLE
SCORE
SITE
Upper Limb
Lower Limb
Peritrochanteric
PAIN
Mild
Moderate
Severe
LESION
Blastic
Mixed
Lytic
SIZE
<1/3
1/3 – 2/3
>2/3
Size is the diameter of cortex involved on plain radiographs
A score of 8 or more is an indication for prophylactic stabilisation
Advantages
 Prophylactic stabilisation:
 Shorter hospital stay
 More immediate pain relief
 Faster and less complex surgery
 Quicker return to premorbid function
 Improved survival
Management objectives
 Decrease pain
 Restore function
 Maintain/restore mobility
 Limit surgical procedures
 Minimize hospital time
 Early return to function (immediate weightbearing)
Non operative management
 Bisphosphonates – modifies bone resorption by
osteoclasts, shown to reduce risk of skeletal metastasis
 Hematologic – correction of anaemia, coagulopathy, DVT
prophylaxis
 Hypercalcemia – hydration, calcium restriction,
bisphosphonates, mithramycin
 Analgesia
 Radiation – most useful in spinal metastases
Radiotherapy
 Used to reduce pain secondary to bone metastases
 Partial in 80%. Complete in 50 – 60%
 Halts progression of bony destruction
 Allows healing of an impending pathologic fracture
 Postoperative local tumor control
Bracing
 Patients with limited life expectancies, severe
comorbidities, small lesions, or radiosensitive tumors
 Upper extremity lesions particularly amenable
 Adjuvant radiotherapy of suscepible tumors required
Operative: principles
 Durable, weight bearing impalnts needed
 PPMA augmentation of construct useful incl. prosthesis
 Bone graft less useful due to prolonged healing time
 Prophylactically stabilise as much bone as possible
 Anticipate hemorrhage due to neovascularisation
 Thus tourniquet, preoperative embolisation
Upper extremity
 Scapula, clavicle – non operative
 Proximal humerus – prosthesis (long stem), intramedullary
nail with multiple screws
 Humerus Diaphysis – locked IM nail > plating
 Distal humerus – prosthesis, retrograde flexible IM nails >
bicondylar plating
 Forearm – Rare. IM nails or plating
Lower extremity
 Acetabular – reconstruction with appropriate
prosthesis
 Femoral neck – hemi- or THR. Cemented. Long stem
 Intertrochanteric – recon nail or prosthesis > DHS
 Subtrochanteric – locked IM nail
 Femur shaft – locked IM nail preferably
cephalomedullary
 Around the knee – locked plating > retrograde nailing
Spinal fractures
 Commonly present with compression fracture
 MRI to differentiate from osteoporosis
 Lesion involving body and pedicle sparing disc highly
suggestive
 Radiotherapy, steroids if no neurodeficits or
impending fracture
Spinal fractures
 Surgery:
 Progression of disease after radiation
 Neurologic compromise
 Impending fracture
 Spinal instability due to pathologic fracture
 Progressive deformity due to pathologic fracture
 Options:
 Minimally invasive kyphoplasty/vertebroplasty
 Decompression and instrumentation
Controversies and future trends
 Optimal length of femoral component of THR
 Criteria for impeding fracture
 Wide resection of solitary metastases – RCC
 Radiofrequency ablation
 Cryotherapy
 Acetabuloplasty – percutaneous PMMA injection
 RANK L modification
 Angiogenesis inhibitors
Summary
 Diagnosis and treatment requires a multidisciplinary
approach
 Aggressive surgical treatment relieves pain, restores
function, and facilitates nursing care
 Biopsy all solitary lesions or refer appropriately
 Understand tumor biology and tailor treatment
THANK YOU

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