CERVICAL CANCER:
RADIATION ONCOLOGIST
PERESPECTIVE
Mohamed farouk akl
PhD clinical oncology
Anatomical considerations:
The cervix is conical in shape and typically measures 3 × 3 cm
portion of the cervix that protrudes into the upper vagina is referred to as the ectocervix
The ectocervix has a central opening referred to as the external cervical os that extends
superiorly to become the endocervical canal and terminate at the internal cervical os to
become the endometrial canal
The endocervix is lined by columnar epithelium, while the ectocervix is covered by squamous
epithelium
The region where these two epithelial layers meet is referred to as the squamocolumnar
junction
Anatomical considerations (cont'd) :
The cervix is attached to the lateral pelvic wall by a pair of ligaments at the base of the
broad ligament referred to as the cardinal ligaments
This ligament contains the uterine arteries and veins. The uterine arteries pass over the ureters
on each side in close proximity to the cervix
Most cervical malignancies arise in the mucosa of the SCJ and invade into the underlying
cervical stroma
Lesions can be exophytic or endophytic and spread by direct extension to the uterine
fundus, surrounding vaginal fornices,parametrial tissues, pelvic sidewalls, rectum and vagina
illustration of the anatomical
components around the
cervix with reference to the
parametrium.
LYMPHATIC DRAINAGE:
The cervix drains into the paracervical lymph nodes which then drain into
the obturator, internal iliac, and external iliac lymph nodes followed by the
common iliac and para-aortic lymph node
follows a stepwise pattern by spreading to the pelvic lymph nodes before
the para-aortic lymph nodes.
CT SCAN FINDINGS IN CA CERVIX:
The normal cervix has a variable enhancement pattern
The primary tumor is heterogeneous or hypodense relative to normal stroma on contrast enhanced
scans
Obliteration of the periureteral fat plane and a soft-tissue mass are the most reliable signs of parametrial
extension
Less than 3 mm separation of the tumor from the pelvic muscles and vascular encasement are signs
of pelvic side wall invasion
Obstruction of the endocervical canal leads to distention of the endometrial cavity with blood, serous
fluid, or pus
The limitations of CT have been lack of consistent visualization of the primary tumor and inaccurate
detection of parametrial invasion
cervical cancer as a hypoattenuating
mass (solid arrow) with diminished
enhancement when compared with the
normal stroma (open arrow) of the
cervix
A low-attenuation mass (arrow) is
present in the cervix, and the
attenuation
of the parametrium is increased
bilaterally
The fat plane
around both ureters has been
obliterated (arrows)
A low-attenuation cervical mass is
present with irregular margins and thick
parametrial soft tissue
Strands.
The vagina (open arrow) is expanded by the tumor growing into it from the cervix. The tumor
involves the lower one-third of the vagina, a finding consistent with stage III disease
The mass extends to the rectum
(open arrow) and also involves the
bladder at the right ureterovesical
junction
enlarged node in the lateral
external iliac chain (solid arrow)
as well as the enlarged node in the
medial chain (open arrow).
MRI findings in normal cervix:
MRI anatomy of the cervix is best delineated on T2W image as four major
zones of cervix
From center to periphery, these are high signal intensity endocervical
canal, intermediate signal intensity plicae palmatae, low signal intensity
fibrous stroma, and intermediate signal intensity outer smooth muscle
MRI findings in normal cervix (cont'd) :
MRI findings in ca cervix:
The basis of the radiologic evaluation of cervical cancer is T2-weighted MRI sequence
Cervical ca is characterized by high signal intensity against low signal of cervical stroma
Sagittal and transverse T2-weighted sequences serve to determine the localization and
size of the tumor as well as the depth of cervical stromal invasion
These sequences are also crucial for excluding extracervical extension and infiltration
of the parametria, vagina, bladder, and rectum
The two critical issues – depth of infiltration and parametrial involvement can be assessed most reliably on
axial images
MRI findings in ca cervix (cont'd) :
On T1-weighted MR images, cervical cancer is similar in SI to cervical stroma. Demarcation from the
corpus uteri, vagina, and parametria is difficult
In the routine clinical setting, T1-weighted sequences are primarily used for lymph node staging
T2WI :The cervical cancer is seen as a hyperintense mass in the surrounding lowsignal-intensity cervical stroma
The cervical cancer
(asterisk) is seen
as a large mass of
intermediate to high
signal intensity that is
delineated against a
very thin margin of lowsignal-intensity cervical
stroma and against the
more hypointense
myometrium of the
uterine corpus
Stage IB cervical cancer
The tumor is surrounded by low-signalintensity cervical stroma
stage IIB
cancer of the posterior cervix with
disruption of cervical stroma
Stage IIA disease: High signalintensity cervical cancer with
infiltration of the posterior
vaginal fornix
Stage IIB disease: Posterior
disruption of the
cervical stroma and a solid
tumor extending in
a posterior direction are signs
of parametrium infiltration
Stage IIB disease: Large solid
tumor extends into the
parametria posteriorly but do
not infiltrate the rectum. Also
see the nodal metastases of
the internal obturator
group, along the internal iliac
artery, and of pararectal nodes
on the left
Stage IIIB disease: T2w image
Cervical cancer with right lateral
parametrial infiltration and
infiltration of the
right pelvic wall
Stage IIIB disease: Cervical
cancer with right lateral
parametrial
infiltration and infiltration of the
right ureter, which is distended as
a consequence
Stage IVA disease: Cervical
cancer with infiltration of the
posterior parametria and
invading the rectum
enlarged
lymph nodes of the common
iliac artery group
on both sides
SIMULATION AND DAILY LOCALIZATION:
Patients may be set up in either a supine position or prone position
use of a belly board to allow setup reproducibility in prone
CT simulation should be done with ≤3 mm slice thickness
-/+ Intravenous contrast
In cases of vaginal involvement, a radiopaque marker should be placed at the caudal extent
of the tumor
bladder and rectal fullness should be maintained
Nodal CTV components:
nodal CTV was subdivided into five regions, i.e. common iliac, external iliac, internal iliac,
obturator and presacral.
CTV components:
CTV components:
CTV components:
The CTV should be divided into three subregions:
CTV1 should include the gross tumor volume (GTV), cervix, and entire uterus
for intact patients or 3-4 cm of the proximal vaginal cuff for postoperative
patients.
CTV2 should extend 2 cm below the most inferior extent of vaginal disease
and parametrium.
CTV3 will include lymph nodes.
CTV components:
GTV (red), cervix (pink),
uterus (blue), vagina
(yellow), parametrium
(green), bladder
(purple), rectum (light
blue), and sigmoid
(orange). Arrow
heads refer to
uterosacral ligaments
and mesorectal fascia.
Arrows refer to the
broad ligament and top
of the fallopian
tube
Parametrium borders:
Parametrium borders:
Parametrium borders:
Parametrium borders:
Stage-specific delineation schemes
for the posterior border of the
parametrium (solid red line):
(a) Non-bulky early-stage (IB1 or IIA)
disease.
(b) Bulky early-stage (IB2 or IIA)
(c) Stage IIB (slight parametrial
involvement).
(d) Stage IIIB disease (massive
parametrial involvement).
Japanese clinical
oncology group
guidlines
Suggested CTV-PTV margin:
Postoperative ca cx:
marked
difference
between uterus
and cervix
positions, with
altered bladder
filling