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Laparoscopic colorectal surgery for cancer:  Is it ready for prime time?
Article by Martin R. Weiser, M.D.
Dr. Weiser is an Assistant Attending Surgeon at Memorial Sloan Kettering Cancer Center and specializes in colorectal cancer. 
This article is provided for information purposes only. It is not intended to be used for medical advice. Please read disclaimer.
ABSTRACT
Laparoscopy, with small incisions and quick recovery, has revolutionized abdominal surgical.  Although mostly applied to patients with benign disease, minimally invasive surgery is now being used in patients with malignant disease as well.  This article focuses on the advantages and disadvantages of laparoscopic surgery for colorectal cancer.  Results from prospective randomized trials will be reviewed regarding this new and popular surgical approach.

INTRODUCTION
Minimally invasive surgery has gained tremendous popularity after the success of laparoscopic cholecystectomy.  With the promise of smaller incisions, less pain, and quicker recovery, minimally invasive techniques have been applied to an increasing variety of surgical procedures.  Laparoscopic appendectomy, splenectomy, and adrenalectomy have been accomplished, and attempts at more complex procedures such as colon and rectal resection have been explored.

Laparoscopic intestinal resection is a challenge.  It requires dissection in multiple parts of the abdomen, isolation and ligation of major arteries and veins, division of colonic attachments, identification and preservation of critical retroperitoneal structures, intestinal division, and reconstruction of bowel continuity.  Laparoscopic colorectal surgery is now being performed routinely for benign processes such as inflammatory bowel disease, rectal prolapse, benign polyps, and diverticular disease.  In the setting of cancer, however, there has been considerably more caution in using these newer surgical techniques.  Concerns over the adequacy of tumor resection, tumor spillage and the possibility of earlier tumor recurrence have been raised.

This review will discuss our current experience with laparoscopic colectomy for malignant disease.  Results from prospective randomized trials (in which patients are assigned by chance to either a laparoscopic or an open colectomy) as well as from well-constructed prospective non-randomized trials, will be reviewed.   Finally, our limited experience with minimally invasive resection for rectal cancer will be discussed.


LAPAROSCOPIC TECHNIQUES AND DEFINITIONS
Minimally invasive surgery involves insufflating the abdomen with carbon dioxide gas, which pushes the abdominal wall away from the intestine and allows the surgeon to work (figure 1).

Figure 1:  The abdomen is insufflated with gas.  Thin specially designed instruments and a magnifying video camera is placed into the abdomen and used for dissection. 
Dissection is performed with specially constructed thin instruments that are placed into the abdomen through small incisions, referred to as ports.  A miniature magnifying video camera is inserted into the abdomen, and the surgeon and assistants view the procedure on monitors in the operating room (Figure 2). 

Figure 2:  The surgeon and assistants perform the operation with the aid of video monitors.
A small incision, often less than one-third the length normally required in open colectomy, is utilized to remove the specimen at the end of the procedure (Figure 3).
Figure 3:  (A) In open surgery for colorectal cancer, a midline incision is often used.

 (B) In laparoscopic colorectal surgery multiple small incision are used for instruments and camera.  The specimen is removed by enlarging one of the incisions.

There is considerable variability in laparoscopic techniques for colon resection.  Some surgeons perform only a portion of the procedure laparoscopically, and then make an incision to complete the resection (laparoscopic assisted colectomy).  Others perform the complete resection laparoscopically. Still others perform hand-assisted laparoscopic surgery, in which the surgeon’s hand is used along with laparoscopic equipment to perform the dissection.

When a minimally invasive procedure cannot be completed via the laparoscopic approach, a larger-than-anticipated incision is created to complete the surgery.  This is referred to as a conversion from the laparoscopic to an open procedure.  The reasons for conversion include: intraoperative complication such as bleeding; the discovery of more advanced disease than anticipated; the presence of adhesions or scar tissue from previous surgery; and an inability to visualize key anatomic structures.  In general, the benefits of laparoscopic surgery are fewer or, in some instances, completely negated in converted cases(1).


FEASIBILITY OF LAPAROSCOPIC COLECTOMY FOR CANCER
A sound oncologic resection is defined as complete tumor removal, with an adequate intestinal surgical margin and removal of the draining lymph nodes.  Many prospective randomized studies have compared the size of the resection margin and the number of lymph nodes removed, following open or laparoscopic colectomy for cancer.  No difference is seen, indicating that laparoscopic colectomy for cancer is feasible from a technical standpoint(2-4).

In the early experience of laparoscopic colectomy for cancer, a few reports described immediate tumor recurrence at the laparoscopic incision sites, referred to as port site recurrences.  It was hypothesized such early cancer recurrence happened after laparoscopy due to tumor shedding and/or accelerated tumor growth, secondary to the presence of gas in the peritoneal cavity.  However, multiple reviews have indicated that this is not the case.  In one such study, which included over 2600 cases, the rate of port site recurrence was approximately 1%, which is similar to that noted in open colorectal surgery {56}.  It is not currently believed that laparoscopic colectomy is associated with early wound recurrences.


ADVANTAGES OF LAPAROSCOPIC COLECTOMY FOR CANCER
What are the advantages to this approach?  The benefits of minimally invasive colectomy for cancer are similar to those seen for benign disease, and are related to less surgical trauma.  The small incisions utilized in laparoscopic surgery are associated with considerably less pain, as reflected in the patient’s reduced postoperative need for narcotic medication.  Related benefits include earlier resolution of postoperative ileus (bowel obstruction caused by temporary intestinal paralysis), quicker resumption of diet, and shorter hospitalization. Some studies have noted fewer complications and overall quicker convalescence following the laparoscopic approach.

Most postoperative pain is related to the size of the abdominal incision.  Therefore, it makes sense that the laparoscopic approach, which uses small incisions, is associated with less pain and less need for postoperative narcotics than the conventional open approach.  Many prospective randomized studies have noted that those patients assigned to the laparoscopic colectomy group needed less pain medication for a shorter period of time{72}{244}{228}.

Patients who undergo a laparoscopic colectomy can resume an oral diet earlier than those undergoing an open colectomy(2;5;6).  The ability to tolerate an oral diet following surgery is related to the return of normal intestinal (peristaltic) activity.  Following surgery, the intestines become paralyzed, referred to as postoperative ileus.  This is caused by many factors, including intraoperative intestinal manipulation, pain, and narcotic usage.  It is thought that all these factors are reduced in laparoscopic surgery, and that this accounts for the earlier resolution of ileus following minimally invasive surgery.

Although minimally invasive surgery does not allow for direct manipulation or visualization of tissues, there has not been an increased rate of complication following laparoscopic colectomy for cancer.  In fact some prospective randomized trials have noted a lower complication rate with the laparoscopic approach(6;7).  The reasons for this may be related to quicker return of pulmonary function(2), less operative blood loss(2;3;6), and increased ambulation following minimally invasive surgery.  This difference is most noticeable in the elderly patient, who is more prone to postoperative complications.  In one cohort study of patients over the age of 75 years, those undergoing laparoscopic colectomy had half the complication rate of those undergoing open colectomy(8).

Laparoscopic colectomy is associated with earlier postoperative recovery.  Patients are generally discharged from the hospital after they can tolerate an oral diet, when their bowel function returns, and when their postoperative discomfort can be controlled with oral pain medication.  Most studies have shown that patients who undergo laparoscopic colectomy are discharged from the hospital 1-3 days earlier than patients who undergo open colectomy (1;5;6).   Long-term convalescence also appears to be quicker following laparoscopic surgery.  One cohort study compared the time it took for patients to return to their usual activity following either laparoscopic or open colectomy.  Patients who underwent laparoscopic colectomy returned to their usual activity, on average, two weeks after surgery, whereas patients who underwent open colectomy reported returning to their usual activity seven weeks after surgery(9).  Another study investigated the ability of elderly patients (>75 years) to resume an independent lifestyle following colectomy.  After open colectomy, close to 25% of these patients required admission to some type of assisted living facility, while only 5% of the laparoscopic patients required admission to an assisted living facility(8).

When long-term quality of life is measured with questionnaires, little difference is seen between laparoscopic and open colectomy(1).  One reason for this is that most quality of life questionnaires were developed for patients with advanced cancer, on chemotherapy, and not for postoperative patients.  These questionnaires do not adequately measure the improvements seen after laparoscopic surgery such as reduced narcotic requirement, shorter postoperative ileus, and faster recovery(1;10).  Newer questionnaires are being developed to study the effects of laparoscopy of quality of life.


DISADVANTAGES OF LAPAROSCOPIC COLECTOMY
The major disadvantage of laparoscopic colectomy is increased operative time.  Most studies report a 30 to 75 minute increase in surgical time using the minimally invasive approach(2;5;6).  The surgeon’s experience is important, and there is a significant learning curve for laparoscopic colectomy.  A recent report notes that operative time decreases significantly the greater the number of procedures performed by the operating surgeon(10).

LONG-TERM RECURRENCE AND SURVIVAL
A recently reported prospective randomized trial has published their long-term tumor recurrence and survival data.  This study notes that patients that underwent laparoscopic colectomy had fewer tumor recurrences and were less likely to die from colon cancer compared with patients that underwent open colectomy(6).  The reasons for this are unclear, but the authors speculate that laparoscopic colectomy is may be associated with less surgical trauma and reduced immune suppression.   This study is relatively small, with a total of 219 randomized patients, and before there is wide acceptance of laparoscopy for colon cancer these results need to be verified by larger, multicenter trials.   One such trial, sponsored by the National Cancer Institute, has recently completed accrual of more than 900 patients and tumor recurrence and survival data should be available in the next few years.

RECTAL CANCER
Laparoscopic rectal resection is considerably more difficult than colon resection, due to the narrow confines of the bony pelvis, and the need to identify retroperitoneal structures such as the nerves that control sexual and bladder function(11).   The few studies concerning minimally invasive rectal resection for cancer indicate that the procedure is safe and feasible; however, more often than not, it cannot be entirely performed laparoscopically, and an incision is required to complete dissection low in the pelvis(12).  This is referred to as the hybrid approach in which a portion of the procedure is performed laparoscopically followed by a small incision to complete the resection and reconstruction(13).   One prospective study noted that patients who undergo hybrid-type rectal resection have an incision half the size, quicker return of bowel function, and significantly shorter hospitalization than patients who undergo open rectal resection(13).  Laparoscopic rectal resection is currently an active field of research.

CONCLUSION AND FUTURE DIRECTIONS
Minimally invasive colectomy for cancer is feasible in experienced hands.  The laparoscopic approach to colon cancer is associated with smaller incisions, reduced pain, less postoperative narcotic requirement, shorter hospitalization, and quicker recovery.  There is no increased complication rate, and some studies have noted fewer complications with the laparoscopic approach.  In most studies, the laparoscopic procedure does take longer than an open procedure; and there is a surgeon learning curve. At this time, there is no indication that the laparoscopic procedure is associated with worse long-term outcome, and one report indicates that patients have improved survival following laparoscopic colectomy for cancer.  However before laparoscopic colectomy can be advocated routinely for colorectal cancer, recurrence and survival data from larger, multicenter randomized trials, such as the one sponsored by the National Cancer Institute must be analyzed.

Minimally invasive surgery for colorectal cancer is an evolving field.  Patients undergoing laparoscopic colectomy for cancer should be monitored in a research setting, with data collection and analysis.    Areas of active research include:  patient selection to reduce conversion rates; the immunologic benefit of minimally invasive surgery; and the application of laparoscopy to rectal cancer surgery.    With further research, the appropriateness of minimally invasive surgery for colorectal cancer patients will be further defined.


AKNOWLEDGMENTS:
The author would like to acknowledge the significant editorial assistance of Jenifer Levin.

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