الفهرس 
HEAD AND NECK SQUAMOUS CELL CARCINOMAOnly 14 pages are availabe for public view
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Abstract
Head and neck cancer includes mucosal and tissues
malignant tumors of this region. Universally are known as
malignant tumors between “dura mater and pleura”. They arise
from mucosa of the aero-digestive tract, salivary glands,
thyroid, parathyroid, bone, soft tissue, neural structures
vascular and skin that part of the human body. Around 650,000
new cases of head and neck cancers all over the world are
diagnosed every year, with a ratio of 3:1 between men and
women. Most of them are in advanced stages (stage III or IV).
Over 90% of head and neck cancers are squamous cell tumors,
most of them are found in the oral cavity and larynx.
In spite of modern treatment modalities and latest
medical equipment, the improvement regarding survival rate
for patients with head and neck cancer had not extremely
grown. This is owing to, on one hand, the great risk of
recurrence in these patients and on the other hand, frequent
metastasis and development of a second primary cancer,
particularly in the respiratory and upper digestive tract.
Early detection of recurrent disease or second primary
cancers may offer a chance of treatment by early salvage
treatment, and possibly a survival benefit. On the other hand,
postsurgical and radiation-induced changes in the normal
tissues may delay the early detection of recurrence by regular
standard examinations of the head and neck including physical examination, endoscopy, computed tomography (CT) and
magnetic resonance imaging (MRI). So, the need for valuable
modalities for diagnosis to overcome these problems become a
necessary.
Functional imaging modalities such as DW/MRI and
PET/CT scan have an innovative role in detecting recurrence of
HNSCC or assessment of treatment response through providing
information on the basic biology such as metabolic activity,
cellularity, vascularity and oxygenation, all potential mediators
of chemoradioresistance.
Diffusion-weighted MR imaging is based on the
diffusion motion of water molecules in the tissues. When
measuring molecular motion with diffusion-weighted MR
imaging, only the apparent diffusion coefficient (ADC) can be
quantified. Encouraging results have also been achieved for
discrimination between residual or recurrent tumors and post
radiation or postsurgical changes in HNSCC.
(PET/ CT) with fluorine-18-fluorodeoxy-D-glucose
(FDG) plays a chief role today in the pre-therapeutic work-up
and post-therapeutic monitoring of patients with head and neck
tumors. FDG-PET/ CT is now usually used in the head and
neck for the delineation of the primary tumor, distant
metastases and second primary tumors. Additional indications
include assessment of post-treatment response, detect
recurrence and an unknown primary tumor. FDG is a glucose that has the identical cellular uptake as glucose but is
metabolically trapped within the cell after enzymatic
phosphorylation to FDG-6- phosphate. Thus, FDG can be used
to quantify glucose metabolic rates.
The present study was done on 8 studies which described
and compared the two different modalities for detection of
recurrence of head and neck squamous cell carcinoma; with
overall number of patients (N=422), with 220 patients used
DW/MRI, and 202 used PET/CT. All articles were published
between 2007 and 2017. A comparison between both
modalities through sensitivity, specificity and accuracy is made
using appropriate statistically methods.
Regarding sensitivity, there is highly significant
difference in sensitivity in favor of PET/CT than DW/MRI,
96% and 93.8% respectively.
Regarding specificity, the fixed-effect model showed
significant increase in specificity in favor of DW/MRI group
than PET/CT group, (90.3 % and 88.6%) respectively.
Regarding accuracy, fixed effect and random-effects
models showed non-significant difference in accuracy between
the 2 groups.