Role of Radiation Flashcards
What aspects of care of head and neck cancer patients is radiology required for?
Diagnosis
Staging
Pre-radiotherapy
Checking treatment response/recurrence
Checking for post-op complications
Dental rehabilitation
What imaging is used in diagnosis of cancer?
Oral cavity- exophytic soft tissue mass or non-healing socket
-> Take OPT to look for bone involvement
If neck lump- ultrasound
What are the radiological signs that may indicate a cancer diagnosis?
Moth eaten bone- areas of ill-defined radiolucency and sclerosis
Pathological fractures
Non-healing sockets
Floating teeth
Unusual perio bone loss- marked around one tooth
Spiculated periosteal reaction
Widening of PDL- with no occlusal trauma
Loss of bony outline for anatomical structures- IDC, walls of antrum
Thinning of cortico-endosteal margin
Atypical aggressive root resorption
What are the other causes of moth-eaten bone?
MRONJ
ORN
Osteomyelitis
What are the common metastases of Adenoid Cystic Carcinoma?
Ribs
Spine
Lungs
What are the signs on ultrasound of cancer in neck lumps?
- LNs- appearing round (should be kidney shaped/rugby ball shaped)
- Enlargement in short axis (if over 10mm- concerning)
- Conglomerate nodes- LNs fuse together
- Necrosis of nodes
- Increased vascularity- normally through hilum, if increased/avascular it is concerning or hilum is lost
- Internal calcification- only present in metastatic SSC/papillary carcinoma of thyroid
- Extracapsular spread- outline of node disappears and extends to involve other tissues like BVs
What else must we consider when looking at neck lumps?
Are they unilateral/bilateral
Are they single or mutliple
What level of neck are they on
What are the levels of the neck?
- Level 1- submental/mandibular region
- Level 2-4- cervical chain
- Level 5 posterior triangle
- Level 6 midline
How does a normal node appear on ultrasound?
- Kidney bean shaped
- Hilum appears white
- Black capsule
What is the difference between FNA and Core biopsy?
FNA- cells for cytopathology
Core biopsy- histopathological sample
What staging is used for tumours?
TNM8
-> different between oropharyngeal, oral cavity, maxillary sinus
-> We consider HPV status and depth of invasion
What is required in order to come to a TNM staging?
Requires imaging in 3D of brain, pelvis, chest and abdomen with large field of view to look for metastases
-> CT
-> MRI
TNM brief description:
T 1-4 (smallest to advanced)
N 0-3
- No nodes up to bilateral
- Size
- Extracapsular spread
Metastases- distant metastases from original site
CT vs MRI:
CT
-> quick
-> good for soft tissue and bone
-> iodinated contrast must be given (enhances tumour)
MRI
-> no radiation
-> Good for soft tissue, marrow involvement, perineurial spread
What must be tested before iodinated contrast can be given for CT?
Blood test- eGFR, creatinine
-> check kidney function
What his used if we cannot find primary tumour?
PET/CT scan (positron emission tomography)
- Nuclear medicine- inject patient with 18-FDG
- Gives little anatomical detail but shows metabolically active tissues (superimposed over CT)
What can cause false positive results in CT scans?
Active muscles
Infection
What occurs after staging scan and biopsy?
MDT meeting
Discuss treatment options
Typically run by radiologists and surgeons
Who are the members of the MDT for head and neck cancer patients?
Surgeons
Radiologist
Oncologist
SLT
Dieticians
Restorative dentist
Clinical support nurse
What is done as part of the dental pre-assessment before radiotherapy?
Treatment and extraction of teeth with obvious disease and dubious prognosis
OPT/PAs
What is imaging to ascertain treatment response used for?
Patient who undergo chemotherapy to check for shrinkage prior to surgery
What conditions may imaging to ascertain treatment response be used for?
Lymphomas
Some sarcomas
Some oro-pharyngeal carcinomas
What is used to check for recurrence in oral cancer?
CT
-> dark areas may be free flap reconstruction as opposed to recurrence
PET/CT- for distant metastases
Why is MRI not used as often for recurrence?
False positves- inflammation in other tissues
What are the post treatment complication of radiotherapy?
ORN- may require bone graft
Infection
What is involved in dental rehab following cancer treatment?
Implant planning following resection and reconstruction
-> may be traditional or zygomatic depending on surgical location
What imaging is used for dental rehab?
CBCT
