Bone Metastasis Grand Round
Download
Report
Transcript Bone Metastasis Grand Round
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