Surgical Staging for Treatment Planning

Along with ovarian cancer debulking and radical hysterectomy, pelvic and paraaortic lymph node dissections are procedures that define gynecologic oncology. Complete pelvic and paraaortic lymphadenectomies (open and transperitoneal) for staging in early-stage cervical cancer are similar in approach to procedures for uterine cancer (see Chapter 9 for details). Lymphatic mapping and sentinel lymph node biopsy for early-stage cervical cancer are also described elsewhere in this book (see Chapter 6 ). This chapter focuses on the rationale for and approach to surgical staging in locally advanced cervical cancer (stages IB2–IVA).

The limitations of the clinical staging system in detecting nodal disease in patients with cervical cancer have led many practitioners to augment their clinical examinations with imaging such as computed tomography (CT), magnetic resonance imaging (MRI), and/or positron emission tomography (PET). Knowledge of status of nodal basins in the pelvis and abdomen is important for both prognostic and therapeutic reasons. First, the presence of positive lymph nodes remains the most important adverse prognostic factor for survival in patients with cervical cancer. Furthermore, the presence or absence of metastases in the lymph nodes guides treatment planning. This may include the choice of primary surgery or radiotherapy as well as determination of the radiation field size—pelvic versus extended field.

Unfortunately, none of the imaging modalities currently available has proven to be particularly sensitive in detecting metastases in paraaortic lymph nodes in patients with locally advanced cervical cancer (stages IB2–IVA). CT has a sensitivity of only 67%, and although MRI may perform well in the detection of parametrial, bladder, and rectal invasion from primary cervical tumors, it performs poorly in the detection of lymph node metastasis. In a meta-analysis of MRI for the detection of lymph node metastasis, Scheidler and colleagues reported an overall sensitivity of MRI of 38%. Other authors have found that MRI had a sensitivity of 0% in the detection of positive paraaortic lymph nodes when compared with surgery and pathologic evaluation.

In many centers, fluorodeoxyglucose (FDG)-PET is used as the best means to detect nodal spread in women with cervical cancer. When compared with the gold standard of surgical staging, FDG-PET has a sensitivity of 84% (95% confidence interval [CI], 68%–94%) in detecting metastatic disease to regional lymph nodes. Unfortunately, that low sensitivity means that 16% of women will be incorrectly categorized as having node-negative disease when the regional lymph nodes actually are harboring disease. The implications of undertreating these patients may be disastrous, given that the survival rate for patients with histologically positive paraaortic lymph nodes treated with extended-field radiation therapy is as high as 50%.

As many as 25% of women with locally advanced cervical cancer (stages IB2–IVA) will have metastatic disease to the paraaortic nodes. Two studies evaluated the sensitivity of FDG-PET/CT in the detection of pathologically positive paraaortic nodes. Both of these studies compared the findings of FDG-PET/CT versus examination of paraaortic lymph nodes surgically resected via a laparoscopic extraperitoneal approach in women with locally advanced cervical cancer (stages IB2–IVA). For women with PET-CT scans showing probable metastases in pelvic nodes and disease-free paraaortic nodes, 21% to 24% were found to have positive paraaortic nodes on standard hematoxylin-and-eosin (H&E) pathologic review of the surgical specimen. Furthermore, when ultrastaging and immunohistochemistry were performed on nodes thought negative after standard H&E pathologic processing, another 2% to 8% of patients had additional micrometastatic disease in these lymph nodes. Had treatment planning been based solely on the best available imaging (PET-CT), a significant number of women with paraaortic metastases would have been undertreated with pelvic irradiation only, when in reality extended-field irradiation was required.

For women with locally advanced cervical cancer, a pretreatment paraaortic lymph node dissection may also provide real therapeutic benefit in addition to the important prognostic and therapy-directing information gleaned through the surgical procedure and pathologic assessment of lymph nodes. Multiple studies have shown that patients with microscopically positive paraaortic lymph nodes that were resected laparoscopically had the same survival rate as patients with pathologically negative paraaortic lymph nodes on surgical staging. Although it is commonly accepted that FDG-PET/CT performs poorly in the detection of microscopic disease spread to the paraaortic nodes in women with locally advanced cervical cancer, it is not known whether surgical staging improves outcomes for these patients.

Traditionally, paraaortic node dissection was performed only through a large vertical midline incision. In the early 1990s, however, the laparoscopic transperitoneal approach was pioneered in the United States and France. The adoption of the laparoscopic approach greatly decreased the morbidity of the paraaortic node dissection, with major complications encountered in less than 2% of procedures.

In the late 1990s, the laparoscopic extraperitoneal approach was developed. This approach improved visualization in obese patients and reduced the morbidity associated with adjuvant radiation in women with locally advanced cervical cancer. In addition, lymph node counts were higher with the extraperitoneal approach compared with transperitoneal or open paraaortic lymphadenectomies.

This chapter describes the laparoscopic extraperitoneal lymph node dissection for surgical staging in women with locally advanced cervical cancer. This approach can be easily adopted to robotic and single-incision platforms.

Anatomic Considerations

Lymphatic nodes and vessels cover the inferior vena cava (IVC) and aorta circumferentially. For gynecologic malignancies, the nodes anterior and lateral to the great vessels are those at risk, although, uncommonly, nodes posterior to the vessels may be involved. This is in contrast to urologic cancers, in which the posterior nodes are at high risk and commonly removed as part of the standard lymphadenectomy. The lower portion of the aorta and vena cava (below the inferior mesenteric artery) receive lymphatic fluid and debris from the common iliac nodes, whereas the nodal basins above the inferior mesenteric artery receive lymph fluid and debris from the lower aortocaval lymphatics and are at the terminal end of the basins draining the uterine fundus and ovaries along the gonadal vessels ( Fig. 8.1 ). Lymph fluid and debris from the liver, spleen, stomach, and bowel flow into lymphatics around their respective pedicles and collect into celiac and mesenteric nodes, located around the origins of their respective preaortic arteries. The aortocaval nodal basins between the inferior mesenteric artery and renal vessels also coalesce with the mesenteric and celiac basins. From these nodes, efferent lymphatics gather to form intestinal lymphatic trunks and form the basis for the thoracic duct, which transports lymph from the abdomen and the intercostal spaces into the general venous circulation, through the left (preferentially) or right subclavicular vein or both. The inferior part of the thoracic duct arises from the convergence of these big collectors located at the level of the L1–L2 vertebrae, between the aorta and the right diaphragmatic pillar. In a small proportion of people, this area forms a sacciform expansion called the cisterna chyli (or Pecquet cisterna). It collects lymph from the whole abdomen, the diaphragm, and the last intercostal spaces before forming the thoracic duct. The size and shape of this cisterna are highly variable.

The transperitoneal approach to the paraaortic nodes requires mobilization of portions of the duodenum, pancreas, and the right colon in order to adequately expose IVC and aorta from the left renal pedicle to the common iliac bifurcations caudally. A standard gynecologic template requires removal of the precaval and lateral (right-sided) nodal basins, inter-aortocaval nodes, and preaortic and lateral (left-sided) nodes. Nodal basins lateral to the aorta and between the aorta and vena cava (inter-aortocaval) are mixed with the postganglionic nerve fibers that arise from the vertebral sympathetic chains. In addition, the lateral and inter-aortocaval nodes are in close relationships with the lumbar pedicles, a possible source of significant bleeding. In rare cases in which disease is detected behind the aorta and vena cava, some lumbar vessels have to be divided to access the retro-aortocaval region (a maneuver called the “split-and-roll” technique by urologists). Above the renal pedicle, the superior mesenteric and celiac nodes are more challenging to approach. However, they are rarely involved in gynecologic diseases; therefore a systematic dissection to this level is not justified as a routine practice.

Of importance during a lymphadenectomy, lymphatic channels are especially large around both common iliac pedicles and the left renal pedicle, especially in the inter-aortocaval space, and laterally to the aorta. Careful division and ligation of these channels to obtain lymphostasis are important in these areas to prevent the secondary development of lymphocysts or chylous ascites. Suture, clips, or advanced vessel sealing devices can be used.

General Instrumentation

Whatever the approach, a laparoscopic paraaortic lymph node dissection does not require sophisticated instruments. Most procedures can be done with a 0-degree or 30-degree laparoscope, two fenestrated grasping forceps, scissors, bipolar forceps, an irrigation-suction device, and endoscopic bags. Advanced vessel sealing devices are useful if available but are not required for the procedure to be safely performed. However, good knowledge of their functioning and limits is mandatory to avoid vascular or nervous damage. Finally, a set of instruments for laparotomy along with some instruments for vascular surgical procedures must be always available in the operating room in case of bleeding that cannot be safely controlled laparoscopically.

For the transperitoneal approach, most surgeons will use three or four trocars (see Chapter 25 for details). For the extraperitoneal approach, three trocars are typically used: a 10-mm balloon trocar for the camera, a 10- to 12-mm operative port, and a 5-mm operative port. Occasionally a fourth 5-mm trocar is necessary.

Extraperitoneal Laparoscopic Paraaortic Node Dissection

Patient and Staff Positioning

Because most nodal basins at risk are located lateral to the aorta, a left internal iliac approach is favored in the absence of obvious right-sided involvement. After general anesthesia has been obtained, a nasogastric tube and a Foley catheter are placed. The patient is positioned supine on the operating room table with a slight curve made by the hips and shoulders as the abdomen is set along the left table edge. The left arm may be positioned “out” at 90 degrees; the right arm may be tucked along the trunk ( Fig. 8.2 ). Slight Trendelenburg and right-sided table tilt are helpful in exposing the retroperitoneal structures, especially in overweight patients. After intraperitoneal exploration (see later), both surgeon and assistant will stand on the patient’s left side, with the monitor positioned across the table on the patient’s right side.

Fig. 8.2, Patient positioning for extraperitoneal laparoscopic paraaortic node dissection.

Technical Description

The operation starts with diagnostic laparoscopy to rule out carcinomatosis or evidence of intraabdominal metastasis. For this purpose, an umbilical trocar for the camera and a 5-mm trocar for an instrument in the right iliac fossa are necessary.

Entry Into Extraperitoneal Space and Placement of Trocars

Entry into the left iliac extraperitoneal space is obtained by either of two methods. The first approach is under direct visualization. A 2-cm skin incision is performed three fingerbreadths above the anterior iliac spine and one fingerbreadth medial to the iliac crest ( Fig. 8.3 ). The fibers of the three muscular layers of the external oblique abdominal muscle, internal oblique abdominal muscle, and transverse abdominal muscle are gently separated with blunt surgical clamps or by use of a spreading motion with surgical scissors. This dissection should be performed in the direction of the fibers to split the muscle without causing bleeding. After splitting of the muscle fibers of the transverse abdominal muscle, the peritoneum should be visible ( Fig. 8.4 ). Another technique for obtaining access to the retroperitoneal space consists of a blunt approach after incision of the skin in the iliac fossa. This is followed by penetration of the surgeon’s forefinger bluntly through the three layers of abdominal wall muscles, under the visual control of the intraperitoneal camera in the umbilicus.

Fig. 8.3, Location of incisions for entry into extraperitoneal space.

Fig. 8.4, View of peritoneum after separation of the three muscle layers of the anterior abdominal wall.

At this point the surgeon’s left forefinger is introduced into the extraperitoneal space to delicately detach the peritoneum from the medial aspect of the transverse abdominal muscle laterally, the quadratus lumborum, and the psoas muscle posteriorly ( Fig. 8.5 ). Under finger control, a 10- to 12-mm trocar is introduced into the flank (on the midaxillary line), midway between the iliac crest and the costal margin ( Fig. 8.6 ). Once this trocar has been placed in the extraperitoneal space, CO ₂ inflation is obtained to a pressure of 12 mm Hg. Careful placement of trocars so as not to injure or rupture the peritoneum is key for obtaining insufflation of the retroperitoneal space and with it the visualization necessary to perform the procedure. The laparoscope is introduced through this port to control the extraperitoneal space and to place the second 5-mm operative trocar under the costal margin (midclavicular line) through the transverse muscle after the peritoneum has been detached and moved away with the finger ( Fig. 8.7 ). The incision used for the finger to assist with placement of the other two trocars is replaced by a 10- to 12-mm balloon trocar placed with direct visualization ( Fig. 8.8 ). The camera is placed in this iliac trocar and the instruments in the other two trocars. The lymphadenectomy can then be started.

Fig. 8.5, External (A) and internal (B) views of detachment of peritoneum from psoas muscle.

Fig. 8.6, Placement of the second trocar under finger control.

Fig. 8.7, Placement of the third trocar under finger control.

Fig. 8.8, Final view of trocar placement for extraperitoneal laparoscopic paraaortic node dissection.

Development of Extraperitoneal Space

Development of the extraperitoneal space begins with elevation of the peritoneum from the psoas muscle laterally and cranially to the level of renal pedicle. The left ureter and infundibulopelvic ligament remain attached to the peritoneum and are elevated above the field of dissection.

Mobilization of Nodal Tissue Along the Lateral Portions of the Left Common Iliac Artery and Aorta

The extraperitoneal laparoscopic paraaortic lymph node dissection separates all of the lymphatic tissue from the great vessels; it is left attached to the peritoneum above it. Once this is completed, the lymphatic tissue is separated from the intact posterior peritoneum and duodenum. Proceeding in this manner minimizes the risk of tearing the peritoneum and losing the ability to keep the pneumoperitoneum in the retroperitoneal space, which is necessary for visualization. The pressure of CO ₂ gas should not exceed 15 mm Hg.

Node dissection starts with the mobilization of the nodal basins along the lateral portions of the left common iliac artery and aorta. The anterior aspect of the left common iliac artery is cleared from nodes from the crossing with the ureter caudally (level of the common iliac bifurcation) up to the left hypogastric nerve, which crosses the aorta and its bifurcation ( Fig. 8.9 ). This nerve is followed laterally to identify the inferior postganglionic fiber arising from the left sympathetic chain. This fiber is anatomically important as a means to identify the inferior mesenteric artery as it crosses at its origin. In retracting this fiber from the aorta, the inferior mesenteric artery is identified, and after identification of the inferior mesenteric artery the fiber can be sacrificed ( Fig. 8.10 ). The dissection proceeds superiorly as nodal tissue is freed from the lateral aspect of the aorta. The origin of the left gonadal artery should be identified next and should be differentiated from a renal polar artery. One way to differentiate these two vessels is to remember that the gonadal artery does not move when the left gonadal vein, found at the most superior portion of the extraperitoneal space, is mobilized. Once identified, the left gonadal artery should be desiccated and divided.

Fig. 8.9, View of common iliac artery and lower aorta after removal of overlying nodes during extraperitoneal laparoscopic paraaortic node dissection.

Fig. 8.10, View of inferior mesenteric artery and sympathetic nerve fibers during extraperitoneal laparoscopic paraaortic node dissection.

The upper border of the extraperitoneal paraaortic lymph node dissection is the left renal vein. This major vessel can be found by following the left gonadal vein, still attached to the peritoneum forming the ceiling of the space, as it flows into the left renal vein. At the level where the left gonadal vein joins the left renal vein, one can often find the azygolumbar vein, also known as the hemiazygous vein, draining into the left renal vein, from the floor of the dissection. The azygolumbar vein is formed by the 12th intercostal vein and ascending lumbar vein.

The nodes dissected from the lateral portions of the common iliac artery and aorta are then elevated from the posterior structures (sympathetic nerve chains and vertebral plane). Care must be taken not to damage the nervous chain (limb sympathetic syndrome) or the lumbar vessels. These vessels are located directly on the vertebral plane and are crossed anteriorly by the sympathetic chain. Following the anterior aspect of the sympathetic chain will facilitate their identification and preservation.

Near the renal vein there is commonly a large lymphatic collector that must be clipped to prevent significant lymphatic fluid collection and possible formation of chylous ascites. The nodes from the lateral portion of the superior aorta are detached from the renal pedicle. At this point, the left renal artery and a possible lymphoazygos anastomosis must be identified, with care taken not to cause damage.

Mobilization of Nodal Tissue Along the Anterior Portion of the Aorta and Vena Cava

The next step is mobilization of the nodes along the anterior portion of the aorta and between the aorta and vena cava (inter-aortocaval nodes). The anterior aspect of the left renal vein is cleared, and the preaortic nodes are elevated from the renal vein cranially to the origin of the inferior mesenteric artery caudally. The inter-aortocaval nodes are then mobilized. The use of clips or advanced sealing devices will prevent small-volume bleeding during this step. While these nodes are being mobilized, the origin of the right gonadal artery will become visible, and it should be immediately desiccated and divided. The anterior aspect of the vena cava is identified. It can be followed cranially to the insertion of the left renal vein and caudally to the level of the inferior mesenteric artery. Precaval nodes are carefully elevated from the IVC. Any vessel going into a node must be preventively desiccated and cautiously divided to prevent a possibly life-threatening hemorrhage. When dissection above the inferior mesenteric artery is completed, the dissection below the inferior mesenteric artery dissection is started.

The inframesenteric dissection is the last step of the procedure. Once the aortic bifurcation is cleared, the left common iliac vein is carefully identified below the promontory. Following the right common iliac artery, the right ureter is identified and elevated and the dissection proceeds to the level of the right common iliac bifurcation. The nodal basins are separated from the artery until the psoas muscle is visible. Then preaortic nodes below the inferior mesenteric artery are elevated until the right hypogastric nerve is visible. The inferior part of the vena cava is just behind this nerve. After this nerve is divided, the anterior aspect IVC is progressively cleared from nodes, with particular care paid to the “fellow’s vein” frequently found at this level.

Removal of Detached Nodal Bundles

The nodal tissue separated from the lateral portions of the left common iliac artery and aorta, the anterior aorta and vena cava, and between the aorta and vena cava are then detached from the posterior peritoneum. Starting at the renal vein, the nodes are separated from the duodenopancreas and the lymphatic channels are carefully clipped and divided to reduce accumulation of lymph and possible formation of chylous ascites. The nodal tissue is separated from the posterior peritoneum by simply sweeping down to common iliac bifurcations. The nodes, stored laterally to the psoas, are placed in a bag and extracted through the iliac port site. After replacement of the balloon trocar, lymphohemostasis is carefully checked and completed if required.

“Preventive Marsupialization” and Completion of the Procedure

To prevent lymphocyst formation, a large fenestration in the left paracolic gutter is created (“preventive marsupialization”). Although feasibly achieved via the extraperitoneal space (taking care not to open the sigmoid colon), it is more easily and safely performed transperitoneally after re-insufflation of the pneumoperitoneum. A 10-cm incision, away from the iliac trocar, is recommended. Placement of intraperitoneal or extraperitoneal drains is not necessary. All trocars are removed and incisions carefully closed. For uncomplicated procedures, patients are typically discharged on the same day as the operation or on the first postoperative day.

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