Transcript Pre and Post-treatment Radiology Work

St. Joe’s Multidisciplinary Head & Neck Cancer Program
Multidisciplinary Approach to Oral Cancer Symposium
Dr. Ashok Balasundaram, BDS,DDS,MDS,MS
Diplomate, ABOMR
Consultant Oral & Maxillofacial Radiologist
Associate Professor, Radiology
Department of Biomedical & Diagnostic Sciences
School of Dentistry
University of Detroit Mercy, Detroit, MI 48208
Email: [email protected]
Ph:313-494-6677
Objectives
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Head, Neck & Oral Cancer Epidemiology
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Indications for Imaging in Oral Cancer
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Current best practices in Imaging
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Pre-treatment
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Post-treatment
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Challenges in Imaging
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Future Directions
Head, Neck & Oral Cancer
Definition:
Head and neck cancer refers to a group of biologically
similar cancers that arise in the oral cavity, nasal
cavity, paranasal sinuses, pharynx and larynx, parotid
glands
Oral cancer sites – lip, buccal mucosa, gingiva, floor of
mouth, tongue, alveolus, retromolar trigone
Etiology of oral cancer – Smoking, alcohol, UV light (lip),
Immune suppression, oncogenic viruses, oncogenes &
tumor suppressor genes
HNSCC - Spectrum
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Laryngeal & Hypopharyngeal
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Nasal cavity & Paranasal sinus
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Nasopharyngeal
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Oral & Oropharyngeal
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Salivary Gland
Oral cancer statistics
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3% of all cancers
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6th most common cancer
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45000 new cases annually
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8650 mortalities (2015)
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94% squamous cell carcinoma
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Annual incidence rate : 7.7 per 1,00,000
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Increased incidence in white males - HPV
Indications for Pre-treament imaging
 Identify disease
(i) Pretreatment assessment of size, extent & pattern of spread
a.
Direct extension over mucosal surface, muscle & bone i.e. depth of
invasion*
b.
Lymphatic drainage pathways
c.
Extension along neurovascular bundles
d.
Metastasis in head & neck from other sites
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Identify unknown primary
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Disease staging e.g. TNM staging
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Determine surgical & therapeutic options
* Brian Trotta, Clinton Pease, John Rasamny, Prashant Raghavan, Sugoto Mukherjee. Oral cavity and Oropharyngeal Squamous
Cell Cancer: Key Imaging Findings for Staging and Treatment Planning. Radiographics 2011; 31(2):339-354.
Current best practices

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CT (Computed Tomography)
a. Ionizing radiation
b. Deep spaces & submucosal spaces
c.
Fast, well-tolerated & readily available
d. Contrast-enhanced CT
e. Less affected by swallowing & breathing artifacts
MRI (Magnetic Resonance Imaging)
a. Non-ionizing radiation
b. T1, T2 & fat-saturation protocols used in cancer imaging
c.
Unenhanced/Contrast-enhanced
d. Superior in detection of tumor spread into bone & marrow
e. No clear advantage of CT for evaluation of nodal disease,
esp. extracapsular spread
Current best practices (contd.,)

PET/CT (Positron Emission Tomography/Computed
Tomography)
a. Metabolic activity of tumor,
i.
SUV – Standard Uptake volume
Higher sensitivity than MRI/CT
c. Combined modality of choice
d. Eliminates false-positive & false-negative findings
e. Agent used: 18-F Fluoro – deoxyglucose
f. FDG dose, timing of scan & injection, imaging time,
surrounding muscular activity and technical factors
associated with image acquisition
g. Characterization of primary tumors, nodal disease
& distant metastasis
b.
FDG PET/CT – Cancer Diagnosis &
Management
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Sensitivity in the detection of recurrent/residual disease –
84 to 100%
Specificity – 61 to 93% (site of occurrence)
Specificity – 95% (regional/distant recurrence)
Specificity – 79% (local recurrence)
False negatives & False positives too soon after chemo and
radiotherapy
Decrease/absent radiotracer uptake on follow-up images
after treatment interval in comparison with uptake on
pretreatment images, is indicative of favorable response
to treatment
High negative predictive value of FDG-PET/CT questions
necessity of neck dissection in patients with negative
findings after initial chemo- and radio-therapy
Cone Beam Computed Tomography (CBCT)
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Routinely used in clinical practice
ENT
Dental implantology
Lower radiation dose
High spatial resolution
Fewer metal-induced artifacts
Not suitable for soft tissue assessment
Potential use in detecting bone invasion
in oral cancer*
* C.Linz, U.D.A.Muller-Richter, A.K.Buck et.al. Performance of cone beam computed tomography in comparison to
conventional imaging techniques for the detection of bone invasion in oral cancer. Int.J.Oral Maxillofac.Surg.2015;44:815.
59 year old male / Gingival growth – left mandible
Indications for Post-treatment Imaging

Response to therapy
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Tumor control
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Detect tumor recurrence
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Deferring Planned neck dissection
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Differentiate tumor recurrence from
radiation/chemotherapy changes
* Naoko Saito, Rohini N.Nadgir, Mitsushiko Nakahira et.al. Post-treatment CT and MR Imaging in
Head and Neck Cancer. What the Radiologist should know. Radiographics 2012;32:12611282.
Early radiation changes

Thickening of skin and muscle
 Reticulation of subcutaneous fat
 Edema and fluid in retropharyngeal
space
 Mucosal necrosis
 Increased enhancement of major
salivary glands
 Thickening, increased enhancement of
pharyngeal walls
* Naoko Saito, Rohini N.Nadgir, Mitsushiko Nakahira et.al. Post-treatment CT and MR
Imaging in Head and Neck Cancer. What the Radiologist should know. Radiographics
2012;32:12611282
Late radiation changes

Accelerated dental caries
 Soft tissue necrosis
 Osteoradionecrosis
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Radiation-induced vascular complications
Radiation-induced lung disease
Radiation-induced Brain necrosis
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Radiation-induced neoplasms

* Naoko Saito, Rohini N.Nadgir, Mitsushiko Nakahira et.al. Post-treatment CT and MR Imaging in
Head and Neck Cancer. What the Radiologist should know. Radiographics 2012;32:12611282
70-year-old male treated for oropharyngeal squamous cell carcinoma
58 y.o male post chemo / RT for
recurrent laryngeal cancer.
Developed radioosteochondronecrosis.
Post-total laryngectomy. Myocutaneous
free flap reconstruction from thigh.
Contributing factors for Osteoradionecrosis
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Irradiation technique
Total radiation dose
Photon energy
Brachytherapy
Field size
Fractionation
Xerostomia
Periodontitis
Pre-radiation bone surgery
Poor oral hygiene
Alcohol and tobacco use
Dental extractions
Tumor location
Proximity of primary tumor to bone
Devitalized bone:
hypoxic,
hypovascular and
hypocellular, inability
to meet demand for
repair.
Surgical complications
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Fistulas, flap necrosis
Tumor recurrence
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Identified as a slightly expansile lesion in
operative bed
Progressive thickening of soft tissues deep to flap
CT – infiltrating slightly hyperattenuating mass
with enhancement, attenuation=muscle
MR – Infiltrative mass with intermediate T1weighted signal intensity, intermediate to high T2weighted signal intensity, and enhancement
High signal on diffusion weighted MR – Recurrence
Low ADC (Apparent Diffusion Coefficient) –
recurrence?
D/D : Vascularized scar, retraction
Perineural spread – risk of local recurrence
Post treatment surveillance Imaging
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US,CT,MR and FDG PET/CT
Early detection
Early Intervention of recurrence
Early intervention of salvage treatment
Differentiate altered anatomy due to surgery from
tumor recurrence
Timing – 4 to 6 weeks after treatment, 3-4 months –
first year, 4-6 months in 2-5 years & annual
afterwards
CT – rapid, identify cervical lymph nodes
MR – sinonasal, salivary gland, nasopharyngeal and
skull base tumors with risk of perineural spread
Post-treatment findings
Summary
Challenges in imaging
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Selection of imaging modality
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Diagnosis
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Evaluate prognosis & treatment
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Tumor recurrence
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Timing of post-treatment imaging
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Combination of modalities to increase
diagnostic yield
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False +ve findings
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False –ve findings
Summary
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Diagnostic value of Pre-treatment and Post
treatment Imaging
Selection of most appropriate imaging modality
US,CT,MRI, FDG-PET, FDG-PET/CT
CT – Identify lesion, staging, mode of therapy
MRI – Identify spread into tissue planes, marrow,
recurrence/treatment-related changes
FDG PET/ PET-CT – Lesion progression, response to
therapy
Future: CBCT for bone invasion – metal artifacts
(scatter)