Cytoreductive Procedures

Edward J. Tanner III, Fady Khoury-Collado, and Dennis S. Chi

PROCEDURE OVERVIEW

Ovarian cancer is one of the few solid tumors in which surgical cytoreduction is indicated for advanced metastatic disease. The most common indication for cytoreductive surgery is suspected or confirmed advanced-stage ovarian cancer. In selected cases, cytoreductive surgery is indicated for other advanced or recurrent gynecologic cancers. The goal of the cytoreductive surgery, defined in terms of the diameter of the largest residual implant, has evolved over the last 3 decades. Although leaving no residual tumor larger than 1 cm is currently defined as “optimal,” maximal survival benefit is associated with removal of all gross tumor. Therefore, the goal should be to attempt removal of all visible disease (complete cytoreduction). The available surgical techniques have similarly evolved during the same period to achieve this goal and now include upper abdominal procedures, tumor ablation techniques, and radical pelvic surgery.

Whether performed for primary or recurrent tumors or following neoadjuvant therapy, the same surgical principles and techniques of cytoreductive surgery discussed in this chapter are applicable.

PREOPERATIVE PREPARATION

Cytoreduction procedures are often lengthy and complex and carry the potential for significant intra- and postoperative morbidities. The patient needs to be evaluated thoroughly to assess whether she is able to tolerate such procedures, to optimize any underlying medical condition, and to plan postoperative care.

As in any patient assessment, the initial step is to take a detailed history, not only of the complaint that led to the suspicion or diagnosis of advanced ovarian cancer, but also of any associated symptoms that can indicate the existence or severity of associated comorbidities. Specifically, any respiratory symptoms should be investigated, because multiple etiologies can coexist. These can be related to the diagnosis of ovarian cancer (eg, pleural effusion, ascites) or simply denote the presence of a medical comorbidity (eg, chronic lung disease, cardiac disease) that either needs to be optimized prior to surgery or may contraindicate an extensive surgery. The presence of nausea and vomiting, abdominal distention, and difficulty with bowel movements may indicate bowel obstruction. A history of recent significant weight loss can point to potential malnutrition. If severe malnutrition is confirmed on laboratory evaluation, preoperative parenteral nutrition should be considered.

A detailed physical examination should specifically look for findings that denote the extent of disease or the underlying condition of the patient, or even suggest a different or coexistent primary malignancy (eg, breast examination, rectal examination). The abdomen is examined closely for ascites, which can cause significant abdominal distention, compromising the respiratory status of the patient and for which a simple paracentesis can provide immediate and significant relief. In the pelvis, a bimanual examination assesses the extent of pelvic disease and gives a reasonable idea about the likelihood of the requirement for a rectosigmoid colon resection.

Routine preoperative testing includes a complete blood count, coagulation studies, metabolic panel including albumin, renal and liver function tests, and an electrocardiogram. Tumor markers, although not mandatory, are commonly obtained as baseline values. Occasionally, they can suggest a different primary malignancy.

Imaging typically includes a computed tomography (CT) scan of the chest, abdomen, and pelvis. A chest radiograph is an acceptable alternative to chest CT. A CT scan of the chest, however, can determine the presence of enlarged mediastinal lymph nodes and pleural tumor deposits, in addition to moderate to large pleural effusions. If the CT demonstrates thoracic disease, an intrathoracic cytoreduction is attempted first.¹ The CT of the abdomen and pelvis helps determine the extent of disease in the abdomen and will assist in the counseling and planning for the procedure.

The patient is informed about the main goal of the surgery and the potential procedures required to achieve complete or optimal cytoreduction. A realistic description of the length and complexity of the procedure, associated complications, need for intensive care monitoring, and expected recovery time is discussed, including the possibility of requiring a temporary or permanent stoma. Transfusion of blood and blood products is frequently needed, and any objections to their use on behalf of the patient should be clearly defined, because this can impact the safety of the planned procedure. At the same time, the possibility of aborting the debulking procedure based on intraoperative findings is discussed.

Patients are instructed to shower the night before or the morning of surgery. Mechanical bowel preparation is not mandatory but is given according to the surgeon’s preference. Prophylactic antibiotics are routinely given, typically cefotetan 2 g, within 1 hour prior to skin incision, with repeated doses given as needed (eg, prolonged surgeries, increased blood loss). Prophylactic antibiotics are discontinued within 24 hours of the operation. Required surgical instrumentation includes a fixed self-retaining retractor (eg, Bookwalter) and electrosurgical unit; automated gastrointestinal stapling devices, an argon beam coagulator, and a vessel-sealing cutting device are highly recommended.

OPERATIVE PROCEDURE

Pneumatic compression devices must be in place and functioning prior to the induction of anesthesia. The dorsal lithotomy position, using Allen stirrups (Allen Medical Systems, Cleveland, OH), is preferred over the supine position because it allows for bimanual examination to determine the extent of tumor involvement in the posterior cul-de-sac and provides access and exposure to the pelvis when performing a rectosigmoid resection and reanastomosis (Figure 30-1). After positioning the patient, the stirrups are rotated into the position they will remain in during surgery to ensure that no undue pressure is exerted on the legs during prolonged periods.

FIGURE 30-1. Patient positioning.

Following positioning, a vertical midline incision is marked from above the xiphoid process to the pubic symphysis. The locations of possible chest tubes and intraperitoneal catheter reservoirs are marked, if anticipated. Antiseptic preparation of the skin follows and is applied from the nipple line to mid thighs. After draping the patient, a sterile catheter is placed in the bladder.

Cytoreductive Procedures

Abdominal Entry

Entry into the abdominal cavity is best achieved through a midline vertical incision from the pubic symphysis to the xiphoid process. Abdominal entry may be hindered by adherence of omental disease to the anterior abdominal wall, although this can be excised without difficulty or bowel injury. If ascites is anticipated, the peritoneum is tented up and entered through a small opening. Fenestrated suction catheters can then be inserted and fluid evacuated in a controlled fashion. A fixed-arm, self-retaining retractor (eg, Bookwalter or Omni) is then placed, and a survey of the abdominal cavity is performed to determine the feasibility of resection. Lateral retractor blades should be placed carefully to avoid femoral nerve injury caused by psoas muscle compression.

Omentectomy

In ovarian cancer, the omentum is a frequent site of tumor metastases, which can vary from microscopic implants to total replacement of the omentum by an “omental cake.” Therefore, omentectomy is part of staging and debulking procedures. An infracolic omen-tectomy is usually sufficient for staging purposes, whereas a supracolic omentectomy is performed when the gastrocolic omentum is involved with tumor. The omentectomy starts by reflecting the omentum cephalad and to the dorsal reflection onto the transverse colon (Figure 30-2). If the omentum is attached to the abdominal wall by tumor implants, it usually can be easily released bluntly or with electrocautery dissection.

FIGURE 30-2. Omental cake reflected cephalad.

The omental dissection starts in the avascular part of the posterior leaf, a few millimeters from the transverse colon serosa, at a level where omental tissue is not replaced by tumor. Using electrocautery, the posterior leaf of the omentum is incised, and with the use of traction and counter traction, the omentum is kept under tension as the incision is extended toward the splenic and hepatic flexures. Where the tumor is adherent to the bowel serosa, sharp dissection with Metzenbaum scissors is used. The lesser sac is entered and inspected for the presence of disease through the space between the anterior and posterior leafs of the omentum. The anterior leaf of the omentum can be taken at any time during the dissection, progressively detaching the omentum from the underlying transverse colon. If tumor implants on the omentum extend laterally to the hepatic and/or splenic flexures, these will need to be mobilized to be able to remove the disease in its entirety. As the omental dissection proceeds toward the splenic flexure, caution should be exercised when placing tension on the omentum, because excessive traction can lead to a splenic capsular tear and troublesome bleeding.

As the dissection proceeds, it is important not to lose the orientation and the direction of the dissection, which can easily happen due to the redundant layers of the omentum. In this context, frequent examination of the transverse mesocolon is critical to avoid an inadvertent injury to the middle colic vessels. When omental vessels are encountered, they can be secured with clamps and ties or using a vessel-sealing device. The right and left gastroepiploic vessels and the intervening gastroepiploic vessels are divided. In rare cases, the tumor densely infiltrates the transverse colon to a point where no plane of dissection can be created without entering the serosa of the bowel. In this case, removing the omental tumor requires a contiguous en bloc resection of involved segment of the colon. The decision whether to proceed with the resection depends on the overall spread of the disease, the extent of the colon segment to be resected, and the likelihood of achieving the cytoreductive goal.

If the supracolic omentum is involved with tumor, a gastrocolic omentectomy is performed. The gastrocolic omentum is divided from its attachment to the greater gastric curvature, and the vessels arising from the gastric arcade are systematically secured. Caution should be exercised at this level to avoid injury to the stomach. It is commonly recommended to decompress the stomach for 24 hours after surgery to avoid bleeding from the vessels secured along the greater curvature of the stomach. We have not routinely followed this practice and have not experienced any incidents of postoperative bleeding.

Right Upper Quadrant Cytoreduction

In patients with advanced ovarian cancer undergoing primary or secondary cytoreductive surgery, the right upper quadrant is a frequent site of disease. The right diaphragm frequently harbors metastatic disease, which can range from superficial peritoneal implants to full-thickness infiltrating tumors. Due to their proximity, the peritoneum covering Morrison’s pouch and Gerota’s fascia is also a frequent site of disease. Tumor implants can also involve the liver surface, the gallbladder, the porta hepatis, and less often, the liver parenchyma. Superficial disease on the liver can be ablated with the argon beam coagulator (ABC) or other ablative devices or superficially excised along with Glisson’s capsule. More extensive liver disease should not be considered an impediment to primary cytoreduction but will frequently require the assistance of an hepatobiliary surgeon (eg, partial liver resections, cholecystectomy, dissection of the porta hepatis). The details of these latter procedures will not be discussed in this chapter. We will instead focus on the procedures most commonly used in cytoreduction of disease in the right upper quadrant, which can be safely incorporated, with appropriate training, into the skill set of the gynecologic oncologist with interest in cytoreductive surgery. We will describe mainly the mobilization of the right lobe of the liver and removal of right diaphragm disease, because the right side is the most commonly affected. When the left diaphragm is involved, a similar approach can be used.

Liver Mobilization

The liver is attached to the anterior abdominal wall by the falciform ligament. The free edge of the falciform ligament contains the round ligament—a remnant of the left umbilical vein. The bare area of the liver, located on its posterior surface in direct contact with the diaphragm, is limited by the coronary ligaments anteriorly and posteriorly and the triangular ligaments laterally.

Liver mobilization is an indispensable initial step in cytoreduction of the right upper quadrant. When omitted, the extent of diaphragm disease is often underestimated. In addition, regardless of the modality for cytoreduction used (eg, tumor ablation, peritonectomy, diaphragm resection), exposure is less than ideal if the liver is not mobilized. The patient, typically in the lithotomy position for the debulking procedure, is rotated to a “right upper quadrant up” position, which is a combination of a reverse Trendelenburg position with inclination of the operating table to the patient’s left side. Self-retaining retractors (eg, Bookwalter, Omni, Goligher) are used to elevate the ribs and expose the diaphragm. The primary surgeon stands either between the legs of the patient or to the patient’s left side.

For mobilization of the liver, the free edge of the falciform ligament containing the round ligament is divided first (Figure 30-3). A suture ligature placed on the lower edge can be used to aid in downward traction on the liver. The liver is separated from its attachment to the anterior abdominal wall as the falciform is divided, close to its liver attachment, in a cephalad direction until its peritoneal layers divide laterally to form the right and left anterior coronary ligaments (Figure 30-4). The dissection continues along the right coronary ligament (Figure 30-5). This dissection can be performed sharply or with electrocautery, the critical point being the identification and avoidance of injury to the right hepatic vein and inferior vena cava. Depending on the adequacy of exposure and the amount of disease present, the dissection of the coronary ligament may continue for a variable amount of length, until it becomes more appropriate to start the dissection laterally by dividing the right triangular ligament and proceed medially (Figure 30-6). The dissection proceeds on either side until the bare area of the liver is exposed. The mobilization of the right lobe of the liver is completed by freeing the right posterior coronary ligament. The different steps of the mobilization do not necessarily follow the same order in every case; the sequence of steps is dictated by the amount of disease and the ease of exposure. Once the bare area is exposed, the liver is gently retracted medially and inferiorly, exposing the entire right diaphragm, Morrison’s pouch, and Gerota’s fascia (Figure 30-7).

FIGURE 30-3. Division of round ligament of liver.

FIGURE 30-4. Division of falciform and coronary ligaments.

FIGURE 30-5. Division of right coronary ligament.

FIGURE 30-6. Division of right triangular ligament.

At this time, optimal exposure of the right diaphragm is achieved and the extent of disease is inspected and palpated to assess for the depth of invasion of tumor implants into the diaphragm muscle.

FIGURE 30-7. Exposure of bare area of the liver after liver mobilization.

Diaphragm Peritonectomy

Several reports have demonstrated the feasibility and improved outcome associated with cytoreduction of disease of the diaphragm.^2,3 After inspection of the diaphragm peritoneum, the area to be excised is outlined. The peritoneal incision usually starts at the level of the costal margin and proceeds posteriorly until all the area involved with tumor is released from the underlying diaphragm muscle (Figure 30-8). During this part, the peritonectomy will alternate between lateral and medial progress, depending on the situation.

FIGURE 30-8. Diaphragm peritonectomy incision.

Several techniques to separate the peritoneum from the underlying muscle have been described, and the surgeon can use whichever technique he or she feels is the most appropriate in each situation. The simplest form is to grasp and put under tension the incised peritoneal edge with several clamps (eg, ring forceps or Allis clamps) and to separate the underlying muscle bluntly by exerting pressure posteriorly and cephalad using a sponge stick. This technique works well when the tumor implants do not infiltrate deeply. In areas where the peritoneal layer is adherent to the muscle (central tendon of the diaphragm, deeper implants), blunt dissection may not be appropriate, and other forms of dissection need to be used. Electrocautery or the ABC can be used to aid in the dissection (Figure 30-9).

FIGURE 30-9. Diaphragm peritonectomy dissection in subperitoneal plane.

The detachment of the involved diaphragm peritoneum will proceed in this way, alternating techniques and direction until all the involved peritoneum is removed (Figure 30-10). Small-vessel bleeding from branches of the phrenic artery and vein often occurs during this dissection and can be controlled with electrocautery, the ABC, or a vessel-sealing device. Once the peritonectomy is completed, the integrity of the diaphragm is verified with a “bubble test”—the right upper quadrant is filled with saline, and the patient is given a maximal inspiration. Bubbles indicate a connection with the pleural cavity. The site of bubbling is identified, and interrupted sutures are placed. The technique for repair of larger defects is described in the following section.

FIGURE 30-10. Diaphragm peritonectomy exposure of muscle.

Diaphragm Resection

Tumor implants firmly adherent to the diaphragm muscle are indicative of muscle invasion or full-thickness involvement and require partial diaphragm resection to clear the tumor. In patients who undergo video-assisted thoracic surgery, full-thickness diaphragm involvement and the presence of pleural implants can be directly visualized and the extent of diaphragm resection planned accordingly. Occasionally, preoperative imaging can point to full-thickness diaphragm involvement. The right phrenic nerve innervates the right diaphragm, entering on the superomedial surface and branching immediately in a radial fashion. Therefore, resections that extend medially carry a higher risk of nerve injury and postoperative diaphragm paralysis.

From the abdominal side, which is by far the most common approach to diaphragm resection, palpation of the involved area can help in identifying the area to be resected. The anesthesiologist is notified about imminent entry into the pleural space with the resultant pneumothorax. When the pleural cavity is entered, the lung is visualized and avoided. The area involved with tumor is outlined and can be resected using electrocautery or an Endo GIA stapler (Figures 30-11 and 30-12). An advantage of the Endo GIA stapler is better delineated edges, which are easier to approximate and suture, with a lesser likelihood of the suture pulling through the muscle because the staple line provides a resistant line of support. The Endo GIA or TA stapling devices (both from Covidien, Mansfield, MA) can occasionally be used in a single step to excise a small lesion while tenting down the diaphragm. Even diaphragm defects as large as 10 cm can be primarily closed without undue tension using interrupted figure-of-eight permanent sutures (1-0 polypropylene) (Figures 30-13 and 30-14). A single or looped running suture has also been used successfully.^4,5 When the defect is too extensive for a tension-free primary closure, a polytetrafluoroethylene patch can be sutured in place with a running suture, starting at the medial edge.

FIGURE 30-11. Full-thickness diaphragm resection using the electrosurgical unit.

FIGURE 30-12. Full-thickness diaphragm resection using the Endo GIA stapler.

FIGURE 30-13. Diaphragm closure with interrupted stitches.

FIGURE 30-14. Completed diaphragm closure.

To prevent postoperative pneumothorax and pleural effusion, air and fluid need to be evacuated from the pleural cavity as the diaphragm defect is closed. A commonly used technique includes passing of a 14- to 16-French red Robinson catheter through the diaphragm defect into the pleural cavity as the closure of the defect is coming to an end (final 1-2 cm). A purse-string or figure-of-eight suture is placed loosely through the diaphragm muscle to surround this remaining connection with the pleural space. As the patient is given several maximal inspirations followed by a Valsalva maneuver, the Robinson catheter, while placed under gentle suction or under a water seal, is removed as the suture is tightened. Persistent pneumothorax is evaluated using the previously described “bubble test.” Alternatively, a chest tube can be placed in the pleural cavity, with minimal morbidity, under direct visualization of the pleural space through the diaphragm opening, and it will effectively drain air and fluid from the pleural space for the first few postoperative days (Figure 30-15).

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