Title: Update on 18FFluorodeoxyglucosePositron Emission Tomography and Positron Emission Tomography Compute
1Update on 18F-Fluorodeoxyglucose/Positron
EmissionTomography and Positron Emission
Tomography/Computed Tomography Imaging of
SquamousHead and Neck CancersSemin Nucl Med
35214-219, 2005
2Introduction
- PET/CT used widelynot adequately evaluated for
head and neck cancer - Its accuracy in initial stagingbetter than
CTsimilar to MRI - Appropriate if sentinel node mapping is performed
in patients with PET studies showing no nodal
disease - Identifying malignant normal size nodes, extent
of viable tumor, and distant disease
3- Initial staging of squamous head and neck cancers
with FDG-PET - Radiotherapy planning
- Carcinoma of unknown primary of squamous cell
origin - Evaluation of response to radiation and/or
chemoradiation therapy
4Initial staging of squamous head and neck cancers
with FDG-PET
- Cervical lymph node
- surgery (type of neck dissection, unilateral
versus bilateral) and radiotherapy field - 18F-fluorodeoxyglucose (FDG)-PETrecurrent head
and neck cancer vs. initial staging of them??
5Initial staging of squamous head and neck cancers
with FDG-PET
- Schöder and Yeung (nodal metastases,
- pretherapy staging??)
- 102 patients with buccal mucosa squamous cell
cancer - Dammann and coworkers, 64 pt FDG-PET, CT, and
MRI - ?in the initial staging
6Initial staging of squamous head and neck cancers
with FDG-PET
- Anatomic information PET/CT vs. PET
- Syed and coworkers( 24 patients )PET/CT for head
and neck cancer before their treatment - ? PET/CT downstaged the disease and changed
the management in 17 of patients, by correctly
assigning areas of increased uptake to fat or
muscle tissue - PET/CT, MRI, and multi-slice CT ??
7Initial staging of squamous head and neck cancers
with FDG-PET
- N0 neck vs. 25 to 30 have metastatic neck nodes
at surgery - 48 patients, in which a sentinel node biopsy with
immunohistochemistry was used as gold standard - ? The detection rate of PET 0 30
- ?40 of cervical nodal metastases are less
than 1 cm in size and PET detection rate for
nodes less than 1 cm is reported at 71
8Initial staging of squamous head and neck cancers
with FDG-PET
- FDG-PET vs. conventional imaging in pretherapy
staging detect contralateral disease and distant
synchronous and/or metastatic disease in the
chest and abdomen
9Radiotherapy planning
- PET-CT with FDG(preradiotherapy staging of head
and neck cancer)sensitivity 96specificity
98.5 - Ciernik and coworkersthe coregistration of
PET-CT with the planning CT images - average deviations x axis 1.2 0.8
mm - y axis
1.5 1.2 mm - z axis
2.1 1.1 mm - Paulino and coworkerserror of less than 5 mm
10Radiotherapy planning
- The target volume may be increased because
metabolically active tumor can be detected in
normal sized nodes - The PET-based GTV is smaller than CT-based GTV in
some patients due to partially necrotic
11Carcinoma of unknown primary of squamous cell
origin
- Cervical nodal metastases from an unknown primary
tumor 2 - Irradiation(the entire pharyngeal mucosa, larynx,
and bilateral neck)reduces the risk of tumor
recurrence vs. significant morbidity,
particularly in terms of xerostomia - CT and/or MRI50
- Endoscopy and directed biopsiessignificantly
higher if a primary tumor is suggested by
radiological exams or physical examination
findings - The most common sitesthe tonsil/tonsillar fossa
and the base of the tongue
12Carcinoma of unknown primary of squamous cell
origin
- Rusthoven and coworkers(between 1992 and
2003)PET was performed after a negative
endoscopy and negative CT and/or MRI ? the
detection rate 27 - Additional local and distant metastases27 of
patients - The relatively high false-positive rate related
to variable physiologic uptake of FDG in head and
neck structures - sensitivity(18 pt) CTPETPET/CT252536
13Evaluation of response to radiation and/or
chemoradiation therapy
- Klabbers and coworkers(all FDG-PET studies for
detection of residual and recurrent head and neck
tumors after radiation and/or chemoradiation
published between 1994 and early 2003) - 3 to 4 months after radiation
14Evaluation of response to radiation and/or
chemoradiation therapy
- Earlier evaluation for many patients treated with
chemoradiation, due to salvage surgery, if
residual disease is present - Salvage surgery within 6 to 8 weeks after
radiation, before postradiation fibrotic changes
develop in the neck - Goerres et al studied(26 patients with advanced
head and neck cancer after concomitant
chemoradiation) and PET findings vs.
histopathology in PET positive cases - clinical follow-up for 6 months in PET
negative cases ?the sensitivity 90.95,
specificity 93.3
15Evaluation of response to radiation and/or
chemoradiation therapy
- Nam and coworkers(24 patients) PET 4 weeks after
definitive radiation therapy - 2 patients with residual disease and only
1/22 patients with a negative PET scan developed
recurrent disease over a median follow-up of 12
months - many as 50 of the recurrences occur more than 15
months after the treatment ? early PET can be
confidently used as a routine
16Evaluation of response to radiation and/or
chemoradiation therapy
- When is the timing of the scan??
- Rogers and coworkerslow sensitivity of 45 for a
1-month posttherapy FDG-PET - Yao and coworkers( 15 patients ) Comparing the
3- to 4-month posttherapy PET data with histology
from salvage surgery ? sensitivity of 100 and
specificity of 82 - In summary, a PET scan performed 2 to 5 months
after therapy has a high NPV so that patients can
be safely followed without intervention