Transcript Carcinoma of the Cervix - Isfahan University of Medical

‫کاهش مرگ در اثر کانسر سرویکس‬
Routine screening programs, including pelvic
examinations and cervical cytologic
evaluation
‫اتیولوژی‬
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HPV
prostitutes
first coitus at a young age
multiple sexual partners
bear children at a young age
Promiscuous sexual behavior in male partners
The mean age of women with
CIN )‫(کنسر غیر تهاجمی یا پره کنسرسرویکس‬is
about 15 years younger than that of women
with invasive cancer, suggesting a slow
progression of CIN to invasive carcinoma.
Natural History and Pattern of Spread
• exophytic growths
• endocervical lesions
• Tumor may become fixed to the pelvic wall by
direct extension or by coalescence of central
tumor with regional adenopathy.
• bladder mucosal invasion.
• Rectum invasion
:‫سرویکس سه مسیر درناژ لنفاوی دارد‬
• The upper branches: follow the uterine artery,
and terminate in the uppermost hypogastric
nodes.
• The middle branches drain to deeper
hypogastric (obturator) nodes.
• The lowest branches follow a posterior course
to the inferior and superior gluteal, common
iliac, presacral, and subaortic nodes.
pattern of metastas
• Cervical cancer usually follows a relatively orderly
pattern of metastatic progression, initially to
primary-echelon nodes in the pelvis and then to
para-aortic nodes and distant sites.
• Even patients with locoregionally advanced
disease rarely have detectable hematogenous
metastases at initial diagnosis of their cervical
cancer.
• The most frequent sites of distant recurrence are
lung, extrapelvic nodes, liver, and bone
The term cervical intraepithelial neoplasia,
refers only to a lesion that may progress to
invasive carcinoma. Although CIN 1 and CIN 2
are sometimes referred to as mild-tomoderate dysplasia
Microinvasive Carcinoma
• definition of microinvasive carcinoma is based
on the maximum depth (no more than 5 mm)
and linear extent (no more than 7 mm) of
involvement.
• This requires a cervical cone biopsy
• With the advent of cytologic screening, the
proportion of invasive carcinomas that invade
less than 5 mm has increased more than
tenfold to about 20% in the United States
Microinvasive Carcinoma
• the risk of metastatic regional disease appears
to be exceedingly low for any tumor that
invades less than 3 mm
• many think that the risk of regional spread
from tumors that have invaded 3 to 5 mm is
sufficiently high to warrant treatment of the
parametria and regional nodes.
Clinical Manifestations
• Preinvasive disease during routine cervical cytologic
screening.
• Early invasive disease usually detected during screening
examinations
• abnormal vaginal bleeding, often following coitus or vaginal
douching.
• a clear or foul-smelling vaginal discharge
• Pelvic pain
• Flank pain (hydronephrosis complicated by pyelonephritis)
The triad of sciatic pain, leg edema, and hydronephrosis is
almost always associated with extensive pelvic wall
involvement by tumor.
• hematuria or incontinence from a vesicovaginal fistula
• External compression of the rectum by a massive primary
tumor may cause constipation
Diagnosis
• an ideal target for cancer screening
• cervical cytologic examination and pelvic
examination has led to a decrease in the
mortality rate
• Only nations with well-developed screening
programs have experienced substantial
decreases in cervical cancer death rates
Screening (The American Cancer Society)
• 3 years after the onset of vaginal intercourse, but
no later than 21 years of age
• Annually :cervical cytology smears
• women who have had three consecutive,
technically satisfactory negative test results may be
screened every 2 to 3 years.
Clinical Evaluation of Patients with Invasive Carcinoma
1. detailed history
2. physical examination,
3. complete blood cell count and renal function and liver
function tests
4. chest radiography
5. intravenous pyelography (or computed tomography [CT])
6. Cystoscopy and either a proctoscopy or a barium enema
study should be done in patients with bulky tumors.
7. CT S or MRI
8. PET
CT S or MRI to evaluate regional nodes, but these studies have
suboptimal accuracy because they fail to detect small
metastases and because patients with bulky necrotic
tumors often have enlarged reactive lymph nodes that may
be free of metastasis.
PET appears to be a very sensitive noninvasive method of
evaluating the regional nodes of patients with cervical
cancer and a useful method for following response to
treatment, although its high cost has prevented widespread
routine use.
MRI can provide useful information about the distribution
and depth of invasion of tumors in the cervix but tends to
yield less accurate assessments of the parametrium.
International Federation of Gynecology and Obstetrics Staging
of Carcinoma of the Cervix
0
Carcinoma in situ, intraepithelial carcinoma.
I
‫ضایعه محدود به سرویکس یا جسم رحم‬
IA
microscopically
Invasion is limited to measured stromal invasion with a maximum depth of 5
mm and no wider than 7 mm.
IA1
Measured invasion of stroma no greater than 3 mm in depth and no wider than
7 mm.
IA2
Measured invasion of stroma greater than 3 mm and no greater than 5 mm in
depth and no wider than 7 mm.
IB
Clinical lesions confined to the cervix or preclinical lesions greater than IA
IB1
Clinical lesions no greater than 4 cm in size
IB2
Clinical lesions greater than 4 cm in size
‫ضایعه از سرویکس گذشته اما به دیواره لگن نرسیده ‪،‬واژن را گرفته اما به یک سوم‬
‫تحتانی واژن نرسیده‬
‫‪II‬‬
‫‪No obvious parametrial involvement‬‬
‫‪IIA‬‬
‫‪Obvious parametrial involvement.‬‬
‫‪IIB‬‬
‫کارسینوم به دیواره لگن رسیده ‪،‬در معاینه رکتال فضای ازاد بین تومور ودیواره لگن‬
‫وجود ندارد‪،‬تومور یک سوم تحتانی واژن را گرفته ‪،‬همه موارد به هیدزونفروز یا کلیه‬
‫از کار افتاده در این مرحله قرار میگیرند مگر علت دیگری داشته باشد‪.‬‬
‫‪III‬‬
‫‪No extension onto the pelvic wall, but involvement of the lower third‬‬
‫‪of the vagina‬‬
‫‪IIIA‬‬
‫‪Extension onto the pelvic wall or hydronephrosis or nonfunctioning‬‬
‫‪kidney.‬‬
‫‪IIIB‬‬
IV
.‫تومور به خارج لگن رفته یا مخاط مثانه یا رکتوم درگیر است‬
IVA
Spread of the growth to adjacent organs
IVB
Spread to distant organs.
Clinical Staging
• FIGO stage is based on careful clinical
examination and the results of specific
radiologic studies and procedures.
• The clinical stage should never be changed on
the basis of subsequent findings.
• When it is doubtful ,case should be assigned
to the earlier stage.
Clinical Staging
• According to FIGO, growth fixed to the pelvic
wall by a short and indurated, but not nodular,
parametrium should be allotted to stage IIb.
• A case should be classified as stage III only if
the parametrium is nodular to the pelvic wall
or if the growth itself extends to the pelvic
wall.
FIGO rules for clinical staging,
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Palpation
Inspection
Colposcopy
endocervical curettage
hysteroscopy
cystoscopy
Proctoscopy
intravenous urography
radiographic examination of the lungs and skeleton
1. lymphangiography
2. Laparoscopy
3. CT, and MRI
:are of value for planning therapy but because
these are not yet generally available and the
interpretation of results is variable should
not be the basis for changing the clinical
stage
Surgical Evaluation of Regional Spread
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transperitoneal
extraperitoneal dissection
laparoscopic lymph node dissection ?
sentinel node ?
surgical staging(controversial)
• patients with microscopic para-aortic or common iliac node
involvement who can benefit from extended-field
irradiation.
• debulking of large pelvic nodes before radiotherapy may
improve outcome. Because patients with radiographically
positive pelvic nodes are at greatest risk for occult
metastasis to para-aortic nodes, these patients may have
the greatest chance of benefiting from surgical staging
• Some authors have advocated pretreatment blind biopsy of
the scalene node in patients with positive para-aortic nodes
and in patients with a central recurrence who are being
considered for pelvic exenteration. The reported incidence
of supraclavicular metastasis varies widely (5% to 20% or
more) for patients with positive para-aortic lymph nodes.
Prognostic Factors
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FIGO stage
Clinical tumor diameter
presence of medial versus lateral parametrial involvement
presence of unilateral versus bilateral parametrial or pelvic wall
involvement
Lymph node metastasis
‫تهاجم به عروق عصبی ولنفی‬
deep stromal invasion (10 mm or more or more than 70% invasion)
parametrial extension
inflammatory response
Uterine-body involvement
histologic features
histologic grade (adenocarcinomas)
‫(هموگلوبولین‬locally advanced )
predictive power:
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Age
peritoneal cytology
platelet count
tumor vascularity
DNA ploidy or S phase
cyclooxygenase-2 expression
growth factor receptors.
HPV DNA
Treatment depended on
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tumor size
stage
histologic features
evidence of lymph node metastasis
risk factors for complications of surgery or
radiotherapy
• patient preference.
Treatment
• HSILs :loop electroexcision procedure (LEEP)
• Although surgical treatment is standard for in
situ and microinvasive cancer, patients with
severe medical problems or other
contraindications to surgical treatment can be
successfully treated with radiotherapy.
• stage IA1: conservative surgery
• stage IA2 and IB1 and some small stage IIA
tumors:‫جراحی یا رادیوتراپی‬
• stages IB2 through IVA: radiotherapy
• Selected patients with centrally recurrent disease after
RT may be treated with radical exenterative surgery
• isolated pelvic recurrence after hysterectomy is
treated with irradiation.
• the routine addition of concurrent cisplatin-containing
chemotherapy to radiotherapy for patients whose
cancers have a high risk of locoregional recurrence.
Stage IB and IIA Disease
• Early stage IB cervical carcinomas can be treated
effectively with combined external-beam
irradiation and brachytherapy or with radical
hysterectomy and bilateral pelvic
lymphadenectomy. The goal of both treatments is
to destroy malignant cells in the cervix,
paracervical tissues, and regional lymph nodes.
Patients who are treated with radical
hysterectomy whose tumors are found to have
high-risk features may benefit from postoperative
radiotherapy or chemoradiation.
stage IB1
• For patients with similar tumors, the overall rate of
major complications is similar with surgery and
radiotherapy, although urinary tract complications tend
to be more common after surgical treatment and
bowel complications are more common after
radiotherapy.
• Surgical treatment tends to be preferred for young
women with small tumors because it permits
preservation of ovarian function and may cause less
vaginal shortening. Radiotherapy is often selected for
older, postmenopausal women to avoid the morbidity
of a major surgical procedure.
stage IB2 (bulky)
• radical radiotherapy
patients who have tumors measuring more than 4 cm in
diameter usually have deep stromal invasion and are at
high risk for lymph node involvement and parametrial
extension. Because patients with these risk factors have an
increased rate of pelvic disease recurrence, surgical
treatment is usually followed by postoperative irradiation,
which means that the patient is exposed to the risks of
both treatments. Consequently, many gynecologic and
radiation oncologists believe that patients with stage IB2
carcinomas are better treated with radical radiotherapy.
concurrent administration of cisplatincontaining chemotherapy
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bulky stage I cancers
lymph node metastasis
involved surgical margins
IB2<=
Radical Hysterectomy
• For premenopausal women :If intraoperative
findings suggest a need for postoperative
pelvic irradiation, the ovaries may be
transposed out of the pelvis.
• The risk of complications may be increased in
patients who undergo preoperative or
postoperative irradiation
Bladder complications
1. decreased bladder sensation
2. chronic bladder hypotonia or atony (3% to 5% )
3. Bladder dysfunction
4. stress incontinence(influenced by RT)
5. bladder contraction and instability(RT post s)
Bowel complications
• constipation and, rarely, chronic obstipation
• small bowel obstruction(RT post s)
Radical Radiotherapy
• excellent survival and pelvic disease control
rates in patients with stage IB cervical cancer.
• Survival rates for patients with FIGO stage IIA
disease treated with radiation alone range
between 70% and 85% and are also strongly
correlated with tumor size.
• for patients with bulky tumors, results may be
improved further with concurrent
administration of chemotherapy
Radical radiotherapy
• goal of radical radiotherapy =cervix, paracervical
tissues, and regional LN
• ERT+BT
• Even small tumors that involve multiple quadrants of
the cervix are usually treated with total doses of 80 to
85 Gy to point A. The dose may be reduced by 5% to
10% for very small superficial tumors. Although
patients with small tumors may be treated with
somewhat smaller fields than patients with more
advanced locoregional disease, care must still be taken
to adequately cover the obturator, external iliac, low
common iliac, and presacral nodes.
Stage IIB, III, and IVA Disease
• With appropriate chemoradiotherapy, even
patients with massive locoregional disease
have a significant chance for cure.
• The success of treatment depends on a careful
balance between external-beam radiotherapy
and brachytherapy that optimizes the dose to
tumor and normal tissues and the overall
duration of treatment.
Stage IIB, III, and IVA Disease
• EBRT shrinking bulky tumor and bringing it
within the range of the high-dose portion of
the brachytherapy dose distribution.
• Subsequent brachytherapy exploits the
inverse square law to deliver a high dose to
the cervix and paracervical tissues while
minimizing the dose to adjacent normal
tissues.
Stage IIB, III, and IVA Disease
• complete the entire treatment in less than 7
to 8 weeks.
• longer treatment courses are associated with
decreased pelvic disease control and survival
rates.
External-Beam Radiotherapy Technique
• High-energy photons
• if 4- to 6-MV photons, four fields are usually
used
External-Beam Radiotherapy Technique
• CT simulation (iliac lymph nodes.)
• Information gained from radiologic studies
such as MRI, CT, and PET improve estimates of
disease extent and assist in localization of
regional nodes and paracervical tissues that
may contain microscopic disease.
• The caudad extent of disease (radiopaque
markers )
organ motion
• positions of the uterus and cervix can vary by
as much as 4 cm from day to day.
• it is usually wise to cover the entire
presacrococcygeal region when locally
advanced cancers are treated.
• some clinicians prefer to use the simpler
technique for patients with bulky tumors.
• Tumor response should be evaluated with
periodic pelvic examinations to determine the
best time to deliver brachytherapy.
• a central block after 40Gy?
Central block
• it can result in overdoses to medial structures
such as the ureters or underdosage of
posterior uterosacral disease. For these
reasons, other clinicians prefer to give an
initial dose of 40 to 45 Gy to the whole pelvis,
believing that the ability to deliver a
homogeneous distribution to the entire region
at risk for microscopic disease and the
additional tumor shrinkage achieved before
brachytherapy
• more than 40 to 45 Gy to the central pelvis
tend to compromise the dose deliverable to
paracentral tissues and increase the risk of
late complications.
Radiation therapy
fields for cervical
cancer
Conventional anteroposterior, AP
(A), and lateral (B) radiation portals
for cervical cancer defined by a
superior field border at the L4-L5
disk space, a inferior border
extending 3 to 4 cm below the
lowest extent of disease or the
bottom of the obturator foramen,
and a lateral edge 1.5 to 2 cm
lateral to the pelvic brim.
Pelvic radiation therapy
field with vaginal marker
Radiograph (A) and
computed
tomography (CT)
scan (B)
demonstrating a
radiopaque vaginal
marker, placed to
aid in localization of
the vagina for
treatment planning.
Extended field
radiation therapy
(EFRT) for cervical
or endometrial
cancer
Extended field
anteroposterior
(AP) radiation
portal covering the
para-aortic nodes.
IMRT
• Unlike standard two-field and four-field
techniques, IMRT makes it possible to deliver
a lower daily dose to the intrapelvic contents
than to surrounding pelvic lymph nodes .
• reduced bone marrow toxicity and acute
gastrointestinal side
IMRT
• IMRT is less sparing of bowel.
• IMRT allows delivery of doses exceeding 60 Gy
with relative sparing of adjacent critical
structures.
• increase error
• influence of internal organ motion and
intratreatment tumor response on the doses
to tumor and critical structures.
• There is no evidence that IMRT can safely be
used as an alternative to brachytherapy for
routine treatment of intact cervical cancer.
• IMRT cannot accurately reproduce the highdose gradients produced with intracavitary
therapy.
• unpredictable variations mandate the use of
large treatment margins
External-beam pelvic irradiation is delivered before
intracavitary insertions in patients with:
• Bulky cervical lesions or tumors beyond stage IIA
to improve the geometry of the intracavitary
application
• Exophytic, easily bleeding tumors;
• Tumors with necrosis or infection
• Parametrial involvement.
high-risk features need ERT
• parametrial involvement, deep stromal
invasion, or positive nodes, positive or close
operative margins,
Volume Treated
• the primary tumor and the pelvic lymph
nodes
• superior border at the L4-5 (external iliac and
hypogastric lymph node)
• inferior border at the inferior edge of the
ischium
• This margin must be extended to the L3-4
interspace if common iliac nodal coverage is
indicated.
• 1.5-cm -2.5 cm margin on the pelvic rim;
• A: Ap simulation film .The 15 by 15 cm portals at
SSD are used for stage IB (broken line), and 18 by
15 cm portals are used for more advanced
disease (solid line). This allows better coverage of
the common iliac lymph nodes. The distal margin
is usually placed at the bottom of the obturator
foramina. B: Standard portal for stage IB tumors
is outlined (solid line indicated as A).. If there is
vaginal tumor extension, the lower margin of the
field is drawn at the introitus (indicated in section
C).
lateral field
• the anterior border of the lateral fields over the
anterior edge of the pubic symphysis
• the posterior margin usually is designed to cover
at least 50% of the rectum in stage IB tumors, and
it should extend to the sacral hollow in patients
with more advanced tumors
• Three-dimensional treatment planning for pelvic
irradiation of cervical carcinoma may reduce the
treated volume, but further research must be
done to determine whether the complication rate
can be decreased as well.
• For stage IB disease, : 15 by 15 cm at the surface
• For patients with stage IIA, IIB, III, and IVA
carcinoma, (18 by 15 cm at surface) are required
to cover all of the common iliac nodes in addition
to the cephalad half of the vagina
• If there is no vaginal extension, the lower margin
of the portal is at the inferior border of the
obturator foramen.
• When there is vaginal involvement, the entire
length of this organ should be treated down to
the introitus
• In patients with tumor involving the distal half
of the vagina, the portals should be modified
to cover the inguinal lymph nodes because of
the increased probability of metastases
Midline Shielding in Ap–PA Portals
• Depending on the institution and
brachytherapy dose administered, midline
shielding with rectangular or specially
designed blocks are used for a portion of the
external beam dose delivered with the Ap–PA
ports
Parametrial Boost
• When parametrial tumor persists after 50 to
60 Gy is delivered to the parametria, an
additional 10 Gy in five or six fractions may be
delivered with reduced AP-PA portals (8 by 12
cm for unilateral and 12 by 12 cm portals for
bilateral parametrial coverage). The central
shield should be in place to protect the
bladder and rectum.
Parametrial boost for cervical cancer
• Treatment fields for a parametrial
boost for a stage IIB cervical cancer.
Para-Aortic Lymph Node Irradiation
• an extended field or through a separate portal
• 45 to 50 Gy to the para-aortic area plus a 5 to
10 Gy boost to enlarged lymph nodes
separate portal
• a “gap calculation( excessive dose to the small
intestines)
• The upper margin = T12-L1
• lower margin at L5-S1
• The width of the para-aortic portals can be
determined by CT scans, MRI,
lymphangiography, FDG-PET scans, or IV
pyelography outlining the ureters.
• The spinal cord dose (T12 to L2-3) should be
kept below 45 Gy by interposing a 2-cm wide
5–half-value layer (HVL) shield on the
posterior portal (usually after 40-Gy tumor
dose) or using lateral ports and the kidneys
below 1,800 cGy
Beam Energies
• 10 MV or higher
• They decrease the dose of radiation delivered to the
peripheral normal tissues (particularly bladder and
rectum) and provide a more homogeneous dose
distribution in the central pelvis.
• With lower-energy photons (Cobalt-60 or 4- to 6-MV
x-rays), higher maximum doses must be given, and
more complicated field arrangements should be used
to achieve the same midplane tumor dose (3 or 4field
pelvic box or rotational techniques) while minimizing
the dose to the bladder and rectum and to avoid
subcutaneous fibrosis
• a metallic prosthesis when using lateral fields
or a box pelvic irradiation technique may
result in a dose decrease of approximately 2%
for 25-MV x-rays and average increases of 2%
for 10-MV x-rays and 5% for 60Co.
Hyperfractionated Radiation Therapy for
Locally
Advanced Cervix Cancer
1.2 Gy to the whole pelvis twice daily at 4- to 6hour intervals, 5 days per weeka total pelvic
dose of 57.5 Gy.A boost dose with
brachytherapy
Concomitant Boost
• On Monday, Wednesday, and Friday of the last
3 weeks, an additional 1.6-Gy boost was given
6 hours after the whole pelvis treatment (14.4
Gy) through lateral fields encompassing the
parametria and primary tumor, for a total
tumor dose of 59.4 Gy.
Three-Dimensional or IMRT
• patients with stage IIB or IVA cervical cancer
with medical illness or severe tumor-related
anatomic distortion that limited delivery of
brachytherapy.
• The toxicity of IMRT was acceptable, and
early tumor responses were encouraging.
IMRT
• Although not as critical in older patients, it is
important to keep in mind that while IMRT has
dosimetric advantages over conventional RT,
IMRT exposes a greater amount of normal
tissues to lower irradiation levels, which has
the potential to increase the incidence of
radiation-induced second cancers .
Brachytherapy
intracavitary techniques
• (137Cs)
• (192Ir)
Remote afterloader
for(HDR)
brachytherapy
A remote afterloader
stores a single (HDR)
radioactive source,
typically Ir-192, and
through a computer
controlled mechanism
advances it within the
catheter or applicator
that has been placed
in the patient.
(HDR) cervix
brachytherapy
applicators
Intrauterine
tandem with (A)
vaginal ovoids,
with (B) vaginal
cylinders, or with a
(C) vaginal ring.
Cervical
interstitial
brachytherapy
Syed-type
interstitial
implant used
for cervical
brachytherapy
Brachytherapy
reference points
Tandem and
ovoid cervical
brachytherapy
illustration of
point A.
High dose rate (HDR)
cervical
brachytherapy
planning
Orthogonal radiographs,
(A) and (B), depicting
placement of intrauterine
tandem and vaginal ovoids.
The images show the
instruments in place in the
uterus and vagina. In
addition, there is barium
contrast in the rectum,
contrast in the Foley
catheter balloon and
radiopaque vaginal
packing.
Vaginal cuff
brachytherapy
applicators
Vaginal ovoids
(A) and vaginal
cylinders (B) for
vaginal cuff
brachytherapy
for endometrial
cancer
For LDR treatments:
• EBRT dose : 45 to 50 Gy
• LDR brachytherapy dose :42 and 45 Gy for
early and advanced cancers
For HDR treatments
• EBRT dose : 48 to 50 Gy
• HDR dose :29 and 30 Gy for early and
advanced cancers.
• The median HDR dose per fraction was 6 Gy
with a median of five fractions.
• computer-generated dose distributions provide
the best means of determining the doses to point
A, point B, bladder, and rectum
• In general, an intrauterine tandem with three or
four sources [15 or 20-10-10-(10) mCi mgRaEq
with LDR] is inserted in the uterus and two
colpostats (2 cm in diameter, loaded with 20 mCi
mgRaEq LDR sources) are placed in the vaginal
vault and packed with iodoform gauze to deliver
0.6 to 0.8 Gy per hour to point A.
• With HDR intracavitary applicators the use of
a rectal retractor has been shown to
substantially reduce the rectal dose
• Interstitial implants with radium (226Ra), 137Cs
needles, or 192Ir afterloading plastic catheters
to limited tumor volumes are helpful in
specific clinical situations (e.g., localized
residual tumor, parametrial extension.
• As Fletcher emphasized, conditions for an
adequate intracavitary insertion include the
following
1. The geometry of the insertion must prevent
underdosing around the cervix;
2. Sufficient dose must be delivered to the
paracervical areas
3. Vaginal mucosal (and, we add, bladder and
rectal) tolerance doses must be respected.
Biology of High–Dose-Rate Brachytherapy for
Cervical Carcinoma
• Late damage rises sharply as the number of
HDR fractions is decreased.
• Displacing the bladder and rectum away from
the HDR sources for the short duration of
therapy may offset the radiobiologic
disadvantage of using a few brachytherapy
fractions
At Washington University
• HDR brachytherapy with sedation and without
anesthesia.
• bladder catheter and gentle packing of the
vagina with iodoform gauze
• anteroposterior and lateral pelvic radiographs
• The usual dose per fraction prescribed at 0.5cm depth is 3 to 6 Gy, and three to six
fractions are given once or twice weekly
HDR
• four fractions of EBRT per week with one HDR
treatment per week
• The number of HDR fractions : two to more
than 10.
• The optimal time–dose–fractionation ?
• In vivo bladder and rectal dosimetry is
performed during the HDR procedure
• Other centers obtain normal tissue doses from
points located on dosimetry films and dose
distribution curves
• Treatment planning for HDR brachytherapy can
be accomplished by a variety of techniques:
1. use of an atlas of applications and source
loadings, to planning of only the initial insertion
followed by replicating the insertion for
subsequent treatments
2. customized optimization of source loading for
each HDR insertion
3. Computer treatment planning and a
reconstruction system used to achieve individual
dosimetry.
Three-Dimensional Brachytherapy Treatment
Planning
• The advantages of in vivo dosimetry are easy
practicability and the possibility to determine
rectal dose during radiation.
• The advantages of computer-aided planning at
ICRU reference points are that calculations are
available before radiation and they can be
taken into account for treatment planning.
• The CT-based planning provides information
on target and organ volumes and dose–
volume histograms.
• The radiography-based planning provides
dimensions and doses only at selected points.
• They predicted that, using therapeutic gain
ratio, similar results would be obtained with
either brachytherapy modality with two to
four fractions of LDR and four to seven
fractions of HDR.
The American Brachytherapy Society published
recommendations
for HDR brachytherapy for carcinoma of the cervix
1. point A to at least a total LDR equivalent of
80 to 85 Gy for early stage disease and 85 to
90 Gy for advanced-stage disease.
2. The pelvic sidewall :50 to 55 Gy for early
lesions and 55 to 65 Gy for advanced ones.
3. As with LDR BT, every attempt should be
made to keep the bladder and rectal doses
below 80 Gy and 75 Gy LDR-equivalent
doses, respectively.
4.Interstitial brachytherapy should be
considered when the tumor cannot be
optimally encompassed by intracavitary
brachytherapy.
5. It was emphasized that the responsibility for
the medical decisions ultimately rests with
the treating radiation oncologist.
Doses of Radiation
• Stage IA (microinvasive) tumors are treated
with intracavitary therapy only (LDR 60 Gy in
one insertion or 75 to 80 Gy in two insertions
to point A, or HDR 35 to 42 Gy in five to six
insertions of 7 Gy to point A, one or two
fractions per week).
• The optimal dose for invasive carcinoma of
the cervix is delivered with a combination of
EBRT whole pelvis, intracavitary, and, at times,
interstitial therapy.
Illustration of IMRT treatment plan to irradiate pelvic lymph nodes, while sparing
organs at risk.
Brachytherapy D
• Fletcher described three conditions that
should be met for successful cervical
brachytherapy:
• (1) the geometry of the radioactive sources
must prevent underdosed regions on and
around the cervix
• (2) an adequate dose must be delivered to
the paracervical areas
• (3) mucosal tolerance must be respected.
verify accurate placement
• Radiographs should be obtained at the time of
insertion to verify accurate placement, and
the system should be repositioned if
positioning can be improved.
Brachytherapy Dose
• Paracentral doses are most frequently
expressed at a single point, usually designated
Point A. This reference point has been
calculated in a number of different ways.
• Optimized source placement can rarely
correct for a poorly positioned applicator
1. The most accepted definition of Point A is a point 2
cm lateral to the cervical collar and 2 cm above the
top of the colpostats, measured at their intersection
with the tandem midpoint on the lateral radiograph
2. an alternative definition places Point A 2 cm lateral
and vertical to the external cervical os.
These definitions can produce quite different dose
estimates. Point A usually lies approximately at the
crossing of the ureter and the uterine artery, but it
bears no consistent relationship to the tumor or
target volume.
• an effort should always be made to deliver at
least 85 Gy (with LDR brachytherapy) to Point
A for patients with bulky central disease.
• without exceeding a dose of 75 Gy to the
bladder reference point or 70 Gy to the rectal
reference point,
• The dose to the surface of the lateral wall of
the apical vagina should not usually exceed
120 to 140 Gy.
• A total dose (external-beam and intracavitary)
of 50 to 55 Gy appears to be sufficient to
sterilize microscopic disease in the pelvic
nodes in most patients.
• Gross disease : a total dose of 60 to 65 Gy
(including the contribution from
brachytherapy treatments).
Palliative Radiotherapy
• Localized radiotherapy can provide effective
relief of pain caused by metastases in bone,
brain, lymph nodes, or other sites. A rapid
course of pelvic radiotherapy can also provide
excellent relief of pain and bleeding for
patients who present with incurable
disseminated disease
• TX for patients with an isolated vaginal
recurrence is similar to that for patients with a
primary carcinoma of the vagina.
• Most patients are treated with external-beam
radiotherapy with or without brachytherapy.
Implants may need to be inserted under
laparoscopic or laparotomy guidance.
After Radical Surgery
• TX Pelvic wall recurrences are often treated
with external-beam irradiation alone,
although surgery and intraoperative therapy
may contribute to local control in selected
patients.
• Reported survival rates usually range between
20% and 40% for patients treated with radical
radiotherapy.
After Definitive Irradiation
• an isolated central recurrence can be cured
with surgical treatment.
• Less extensive operations, such as radical
hysterectomy or anterior exenteration, are
reserved for selected patients with small
tumors confined to the cervix or lesions that
do not encroach on the rectum, respectively.
Unresectable disease
• Intraoperative irradiation ( involves the pelvic
wall)
• chemotherapy alone (previously discussed);
response rates and prognosis are generally
poor.
• When brachytherapy is used, most
investigators have reported survival rates
similar to those for patients with carcinomas
of the intact cervix.