Oncology Anatomy

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Oncology Anatomy

• Darrel Bell
• Todd Tillmanns
• February 10, 2005

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Objectives

• Describe the gross and histologic anatomy of the
  pelvic organs and breast.
• Describe the vascular, lymphatic, and nerve
  supply to each of the pelvic organs
• Describe the anatomic relationship between the
  reproductive organs and other viscera, such as
  the bladder, ureters, and bowel.
• Describe the likely changes in the anatomic
  relationships of the pelvic and abdominal viscera
  created by surgical or radiation treatment for a
  malignancy of the pelvic organs.

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Objective 1 and 2

• Describe the gross and histologic anatomy of the
  pelvic organs and breast.
• Describe the vascular, lymphatic, and nerve
  supply to each of the pelvic organs

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Pelvic Contents

• Uterus
• Fallopian tubes
• Ovaries
• Cervix
• Vagina
• Bladder
• Ureters

• Bones
• Muscles
• Fascia
• Colon
• Rectum
• Glands
• Urethra

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The Female Breast

• Extends from lateral border of the sternum to the
  midaxillary line and vertically from the 2nd to
  the 6th rib
• The axillary tail extends along the inferolateral
  edge of the pectoralis major muscle
• The nipple is the greatest prominence of the
  breast and is surrounded by a circular pigmented
  area of skin called the areola, which is usually
  found at the 4th rib
• The Areola contains sebaceous glands which
  provide an oily protective lubrication during
  pregnancy/lactation

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The Milking System

• Lactiferous ducts
• Independently drains from nipple and are fed by
  lactiferous sinuses just deep to the areola
• Lactiferous Sinus
• Dilated lactiferous ducts which store milk
• Mammary glands
• Modified sweat glands, which enlarge during
  pregnancy
• Connected to sinuses by lactiferous ducts
• Scattered throughout the breast

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The Internal Support

• Suspensory ligaments of Cooper
• support the mammary glands by attaching them to
  the overlying dermis
• Retromammary space
• is a potential space between the deep pectoral
  fascia and the breast tissue, which allows for
  some movement of the breast

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Histology
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Vasculature of the Breast
?

• Arterial/Venous Supply
• Medial mammary branches of the internal thoracic
  artery
• Lateral mammary branches of the lateral thoracic
  artery
• Posterior intercostal arteries
• Lymphatic Drainage
• 75 drains laterally to the axillary lymph nodes,
  which creates a triangle between posterior,
  anterior, and lateral nodes and follows
  subclavian vein to supraclavicular nodes
• 25 drains medially to parasternal nodes or to
  the opposite breast
• Retroareolar?superficial lymphatics?external
  mammary, axillary, central axillary vein nodal
  groups
• Deep or fascial lymphatics?Rotters
  nodes?subclavicular nodes
• Medial coursing lymphatics? Internal thoracic?
  subdiaphragmatic lymph nodes and liver lymph
  nodes
• Innervation
• 4th through the 6th intercostal nerves

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Normal Breast
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Fibroadenoma
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Fat Necrosis
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Pagets Disease
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Infiltrating Ductal Carcinoma
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The Uterus
?

• Arterial/Venous Supply
• Uterine, ovarian, and vaginal artery
• Lymphatic Drainage
• Fundus aortic/lumbar/pelvic lymph nodes
• Body within broad ligament to external iliac
  nodes
• Cervix internal iliac and sacral lymph nodes
• Innervation
• Sympathetic and parasympathetics run through the
  uterovaginal plexus (which travels with the
  uterine artery) from the inferior hypogastric
  plexus and lumbar splanchnic nerves

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The Uterus continues
?

• The Wall
• Perimetrium, myometrium, endometrium
• The Endometrium
• Stratum basale premordial glands and densely
  cellular stroma
• Stratum functionale responds to fluctuating
  hormone levels, includes Stratum compactum and
  spongiosum,
• Stratum Compactum
• Consists of the necks of the glands and densely
  populated stromal cells
• Stratum Spongiosum
• Consists primarly of glands with less densely
  populated stroma and large amounts of
  interstitial tissue

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Proliferative Secretory
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Leiomyoma
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Adenomyosis
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Endometrial Hyperplasia
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Endometrial Adenocarcinoma
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The Fallopian Tubes

• Arterial/Venous Supply
• Terminal branches of the uterine and ovarian
  arteries found in the mesosalpinx
• Lymphatic Drainage
• Separate and distinct from the uterus
• Drains to the internal iliac nodes and the aortic
  nodes at the level of the renal vessels
• Innervation
• Sympathetic and parasympathetic from the uterine
  and ovarian plexus. Sensory nerves come from T11,
  T12, and L1

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The Fallopian Tubes continues
?

• Facts
• endometrial ostia 1.5 mm, abdominal ostia 3
  mm, length 10-14 cm
• Four segments
• Intramural, isthmic (narrowest internal
  diameter), ampullary, infundibulum
• Fimbriae
• the largest attached to the ovary is called
  fimbria ovarica
• Layers
• Serosa, Adventia (vessels), muscle, mucosa
  (plica, cilia)

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Histology
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Histology continues
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Ectopic
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The Cervix
?

• Arterial/Venous Supply
• Descending branch of uterine artery, numerous
  anastamoses between vaginal and middle
  hemorrhoidal arteries
• Major arterial supply at 3 and 9 oclock (hence
  stay sutures)
• Lymphatic Drainage
• Complex obturator, common iliac, internal
  external iliac, and visceral nodes of the
  parametria
• Innervation
• Endocervix is rich in free nerve endings, women
  can vasovagal during instrumentation of uterine
  cavity
• Exocervix innervation is not as concentrated

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Exocervix Endocervix
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More of the Cervix
?

• Squamocolumnar junction (SCJ)
• Junction between columnar and squamous epithelium
• Dynamic puberty, pregnancy, menopausal, original
  vs active SCJ
• Neonate exocervical, menopausal endocervical
• Transformation zone
• Metaplasia advances from the original SCJ inward,
  toward the external os, over the columnar villi
• This process creates the transformation zone
• Nabothian Cysts
• Endocervical glands covered during the
  metaplastic process

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Squamocolumnar Junction
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Chronic Cervicitis
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Cervical Intraepithelial Neoplasia
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Cervical Cancer
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The Ovaries

• Arterial/venous supply
• Arteries come from aorta, descend in the
  retroperitoneal space, cross anterior to the
  psoas muscle and internal iliac vessels. The
  left ovarian vein drains into the left renal vein
  and the right drains into the IVC
• Lymphatic drainage
• to the aortic nodes and the level of the renal
  veins
• Innervation
• accompanies the ovarian vessels

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The Ovary continues

• The ureter runs close to the ovarian fossa
• Germinal epithelium is cuboidal
• Ligaments ovarian and infundibular pelvic
  (vessels)
• Ovarian fossa
• A depression in the peritoneum where the ovary
  rests in nulliparous women

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Germinal epithelium - cuboidal
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Ovarian stroma - follicles
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The Bladder
?

• Arterial/Venous supply
• Superior and inferior vesical, middle
  hemorrhoidal
• Innervation
• Sympathetic and parasympathetic
• External sphincter innervated by the pudendal
  nerve
• Urachus
• Adult remnant of the embryonic allantois
• Trigone
• Consists of ureteric orifices and the internal
  urethral orifice

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The Ureters

• Arterial/venous supply
• Numerous anastomoses from many small vessels that
  form a longitudinal plexus in the adventitia of
  the ureter
• Parent vessels include renal, ovarian, common
  iliac, hypogastric, uterine, vaginal, vesical,
  middle hemorrhoidal, superior gluteal
• Four arteries cross anterior to the ureter
• Right colic, ovarian, ileocolic, and superior
  mesenteric

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Branches of the Internal Iliac
?

• Anterior
• Obturator
• Internal Pudendal
• Umbilical
• Superior,middle, inferior vesical
• Middle rectal (hemorrhoidal)
• Uterine
• Vaginal
• Inferior gluteal

• Posterior
• Iliolumbar
• Lateral sacral
• Superior gluteal

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Objective 3

• Describe the anatomic relationship between the
  reproductive organs and other viscera, such as
  bladder, ureters, and bowel

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Relationships

• Anterior uterine fundus lies on the superior
  surface of the bladder
• The small intestines lie on the superior aspect
  of the uterine fundus
• The ureters (which carry water) are posterior to
  the ovarian artery
• Water under the Bridge

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The course of the ureter

• Medial leaf of the parietal peritoneum and in
  close proximity to the ovarian, uterine,
  obturator, and superior vesical arteries
• The uterine artery lies on the anterolateral
  surface of the ureter for 2.5 3.0 cm
• At the ischial spines, the ureter goes from the
  uterosacral ligaments medially to the base of the
  broad ligament
• The ureter enters the cardinal ligament and then
  goes medially to enter the bladder

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The Ureters
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Finding the Ureters

• Incise the round ligament gaining access into the
  retro-peritoneal space. Continue the incision in
  the retroperitoneal space cephalad parallel to
  the infundibulopelvic ligament. Abate the
  incision when the cecum or pelvic brim is
  encountered on the left. Place your fingers
  laterally into the retroperitoneal space so as to
  encounter the psoas muscle on the lateral aspect
  of the pelvis beneath the tied off portion of the
  round ligament. Now using the psoas muscle as a
  guide, let your fingers slide down the psoas
  medially until you encounter the pulsation of the
  external iliac artery. With two fingers
  straddling the external iliac artery move
  cephalad up the artery until the bifurcation of
  the common iliac is encountered. At this point
  gently move your fingers medially and the ureter
  should come into view just below your fingers.

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Retroflexed vs Anteflexed
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Retroverted vs Anteverted
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Pelvic Node Sampling

• Landmarks
• Bifurcation of common iliac, external iliac,
  hypogastric arteries/veins, ureter
• Borders
• Superior Middle of common iliac artery
• Lateral Genitofemoral nerve
• Distal Circumflex iliac vein
• Medial Ureter

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Para-aortic Node Sampling
?

• Landmarks
• Aortic bifurcation, IVC, ovarian vessels,
  inferior mesenteric artery, ureter, duodenum
• Borders
• Lateral ureter
• Distal Middle of common iliac artery
• Medial around IVC and aorta
• Superior inferior mesenteric artery or renal
  vein

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Perirectal Space
?

• Margins
• Anteriorly cardinal ligament
• Posteriorly sacrum
• Medially ureter and rectum
• Laterally hypogastric vessels

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Paravesical Space

• Margins
• Medially superior vesicle artery and bladder
• Laterally external iliac vessels and obturator
  internus
• Posteriorly cardinal ligament
• Anteriorly pubic symphysis

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Objective 4

• Describe the likely changes in the anatomic
  relationship of the pelvic and abdominal viscera
  created by surgical or radiation treatment for a
  malignancy of the pelvic organs

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Surgical Anatomic Changes

• Removal of pelvic organs creates a potential dead
  space which is replaced by other structures,
  fluid, or connective tissue
• e.g. small intestines fill space previously
  occupied by the uterus
• This increases the risk of adhesions and
  obstruction
• Vaginal axis is not altered, but does rotate
  anteriorly to become almost a straight tube
  following a hysterectomy.
• Vaginal length may be shortened during a radical
  hysterectomy
• Removal of the uterus minimally displaces the
  dome of the bladder posteriorly

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Radiation Anatomic Changes

• Results in fibrosis and scarring that tends to
  fix anatomic relationships and limits their
  mobility
• Parametrial fibrosis is often described as smooth
  induration extending to sidewalls
• Radiation treatment of the vagina is associated
  with loss of pliability and volume
• Scoring changes late toxicity
• SOMA Subjective, Objective, Management
  criteria, Analytic laboratory and imaging
• LENT Late, Effect, Normal, Tissue

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Pathophysiology Changes by XRT

• Small Intestines
• Modest doses cause malabsorbtion of fat and
  hypermotility.
• Higher doses result in diarrhea, malabsorbtion of
  fat, and leakage of albumin into the bowel.
• Obliterative arteritis may occur and adhesions
  with bowel obstructions may occur.
• Incidence of SB injury is 15-25 if paraaortic
  radiation is 50-55 Gy when added to WPR.
  Terminal ileu is the most common site for injury.
• Colorectum
• Radiation injury to the large bowel is less
  likely than the small bowel.
• Colitis and rectal strictures are major concerns.
• Vagina
• Desquamative changes may occur resulting in acute
  radiation vaginitis. As well vaginal stenosis
  may occur and can be prevented with the use of
  vaginal dilators.
• Eifel and colleagues studied 1784 patients with
  stage IB cervical carcinoma treated with WPR.
  Greatest risk for complications was in the first
  three years. Colon complications declined after
  2 years while urinary complications continued at
  0.3 per year with 20-year actuarial risk of
  major complications of 14.4

PEREZ CA, Principles and Practice of Radiation
Oncology 3rd Edit. 1998 pp. 193
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Pathophysiology Changes from Chemotherapy

• Chemotherapy alone does not apparently produce
  significant late GI complications
• Drugs such as 5-FU produce diarrhea and mucositis
  
• However, late effects are seen only in
  combination with XRT.

PEREZ CA, Principles and Practice of Radiation
Oncology 3rd Edit. 1998 pp. 193
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Tissue sensitivities of various organs (most vs.
least sensitive kidney, liver, ovary)
?

• Tolerance depends on fractionation, total dose,
  dose rate, and volume irradiated
• The lower the dose rate and the higher the
  fractionation, the better normal tissue tolerance
• Increased volume results in decreased tolerance
• Normal tissue of cervix/uterus can tolerate
  20,000 30,000 cGray in 2 weeks
• Large bowel (rectosigmoid) is the most sensitive
  of pelvic structures to radiation
• Vaginal surface dose usually limited to 120-140
  Gray
• Recommended gonadal dose limits from birth to age
  30 is 10 cGray

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Whole Body Irradiation

• Whole body lethal dose is 4 gray
• Whole body gt100 gray leads to cerebrovascular
  collapse in hours
• Whole body 5 - 12 gray leads to death in days
  from bloody diarrhea
• Whole body 2.5 - 5 gray will wipe out bone marrow
  and leads to death in weeks

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Sources

• Droegemueller, et al. Comprehensive Gynecology,
  4th Edition, 2001
• Berek, et al. Novaks Gynecology, 13th Edition,
  2002.
• Moore, et al. Clinically oriented anatomy, 4th
  Edition, 1999.
• Pathology Histology slides The Internet
  Pathology Laboratory for Medical Education
• Lobo, et al. Obstetrics Gynecology, 1st
  Edition, 2003
• Santoso and Coleman. Handbook of Gyn Oncology,
  2001.