Miguel A. Rodriguez-Bigas, M.D.
Professor
Department of Surgical Oncology
The University of Texas MD Anderson Cancer Center
Hello. I'm Miguel Rodriguez-Bigas. I am Professor of Surgery in the Department of Surgical Oncology at The University of Texas MD Anderson Cancer Center. Today, we're going to talk about colorectal cancer. And we're going to talk about the role of surgery in the treatment of colorectal cancer.
At the conclusion of this talk, you should be able to recognize the types of bowel resection used in the treatment of colorectal cancer, discuss intestinal diversions, and discuss metastasectomy in the treatment of patients with advanced disease.
Surgery in patients with colorectal cancer is the only therapy required for early stage cancer. That is, for Stage I, which is the tumors localized within the bowel wall, surgery should be sufficient. For Stage III patients with lymph node involvement, surgery will be part of multimodality treatment. In the colon, in general, we treat those patients with chemotherapy in addition to surgery, and in the rectum, these patients receive chemotherapy and radiation.
The importance of chemotherapy is that it increases the likely --- the likelihood of cure in surgically treated high-risk cases. Chemoradiation, which is used in most of the time in the rectum, reduces local recurrence by about 50 percent in rectal cancer, and improves sphincter preservation.
So, what are the principles of surgery in colorectal cancer? It's going to be removal of the primary tumor with adequate margins. It means that there must be adequate margins around the tumor as well as proximal and distal to the tumor. In general, in the colon, at least 5 cm with the principle blood supplies is required in terms of resection for cure. In the rectum, we usually like to get at least 2 cm of distal margin. But, when we -dis --- remove the fat, we would like to get at least 5 cm, unless there are sphincter saving procedures and this patient has being treated with neoadjuvant chemoradiation. The rec --- the surgery in colorectal cancer may require the removal of adjacent organs when the tumor is attached. That means that is --- if the tumor is attached to the primary --- to any other organs, for example, the bladder or the uterus, it is not right to dissect the adhesions. What we need to do is remove the tumor en bloc, in one piece. If we dissect between the adhesions between these organs, 40 to 80 percent of the time, there's going to be tumor. And we're going to compromise local recurrence and cure. We also have to treat the draining lymphatics. And, we have to restore organ integrity, if possible.
"What are the types of bowel resection?" Hemicolectomy or segmental resection: it depends on where the tumor is located. And, as we'll see in a later slide, we'll show diagrams of where these resections are ---- what are --- what is involved. Low anterior resection, which removes part of the rectum or the low sigmoid. Abdominoperineal resection, where the rectum is removed and an end colostomy is formed. And, extended resections, again, depending on the location of the tumor, the presence of obstructions, whether there are multiple tumors, and hereditary cancer syndromes. All of those will take into account what type of resection we will have to do.
In the diagram, you will see by different colors the segments of the bowel that are removed in general. A right hemicolectomy in moving --- removing of the cecum, ascending colon, and proximal transverse colon, part of which is seen in this slide in green. The transverse colon could remove --- could involve removal of the transverse colon, which is in green, or doing an extended hemico --- right hemicolectomy which would include up to the descending colon. And, similarly, you can see by the colors what we could be resecting. For example, a descending colectomy, a sigmoid colectomy, and in the lower aspect of the slide, you will see the rectum. And, the rectum depending on what we do, we either can do a segmental resection of the rectum and connect it to a piece of the large bowel. Or we can do an abdominoperineal resection or removal of the rectum and the anus, and then do an end colostomy. This is in cases where the tumors involve the sphincter muscle.
You can see here an abdominoperineal resection where we see the rectum has been removed right here with an end colostomy.
"What are surgical diversions?" These are openings in the abdominal wall which connect an --- an internal organ or the secretions of that internal organ to the skin. For example, a pancreatic fistula connects the pancreatic fluid to the skin. A gastrocutaneous fistula, gastric contents or stomach to the skin. And a colostomy connects the colon or the fecal material exiting through the skin. Similarly, an ileostomy connects the ileum or the small bowel, that part of the small bowel which is the ileum, outside to the skin. They could be loop stomas which are not completely diverting, or end stomas which are completely diverting, like we saw in the previous diagram of the abdominoperineal resection. Each of these types of procedures have indications. In general, if there is an obstructing tumor in the rectum, a loop colostomy could be performed or an end colostomy. If an end colostomy is performed, the distal part of the bowel has to be vented because of the risk of a closed loop obstruction with rupture of the segment that is left in place.
We see here an end colostomy. In here, we see a loop --- I'm sorry, an end ileostomy.
These diversions could be either temporary or perman --- permanent depending on the situation. A permanent stoma is used when the sphincter muscles cannot be preserved, as mentioned already in the abdominoperineal resection. Or, it could be done for palliation purposes in a resectable disease. Temporary, is used to protect an anastomosis or for decompression prior to definitive resection of a patient who has an obstructive tumor.
"What about the role of liver --- of metastasectomy?" Approximately 25% of patients with colorectal cancer present with metastases at the time of diagnosis. The most common sites are liver and lung. Unfortunately, the majority of them are unresectable. But there is a group of patients that will be resectable. And, the optimal treatment would be removal of the primary tumor with the metastases, if possible. However, this may not always be optimal.
The factors to consider when evaluating for possible metastasectomy include the performance status. "How is the patient doing?" "Is the patient mobile?" "Is he work --- is he or she working?" "Are they having any symptoms?" The status of the primary tumor: "Does it invade another organ?" "How much of a surgery would that be." For example, if it invades the bladder at the trigone, then a pelvic exenteration removal of the bladder, rectum and anus may be necessary as well as the prostate in a male. So, this has to be taken into consideration, the status of the primary tumor. The symptoms. "Is the patient symptomatic?" And, obviously the status of the metastases. "Is it single?" "Is it multiple?" "Can it be resected?" Or, "Are we going to be leaving disease behind?" All of these factors have to be considered because there is no use of doing surgery if you are leaving tumor behind.
The treatment of synchronous metastases, that is, metas --- metastases present at the time of diagnosis, may involve chemotherapy followed by synchronous resection of the primary tumor and the metastases. For example, resection of the liver as well as a colon primary tumor, or resection of the primary tumor followed by chemotherapy and resection of the metastatic disease, staged resection. That --- We do that at times in symptomatic primary tumors or in patients that we think that they're going to obstruct. Or they're going to develop problems. In addition, this is what has been called the classic approach, where we try to resect the primary tumor followed by the metastasectomy.
Treatment of metachronous metastases, that is, metast - metastases that appear some time after resection of the primary tumor, involve, in general, chemotherapy followed by resection, followed by chemotherapy.
With the newer chemotherapeutic and biological agents, previously unresectable disease can be converted to resectable disease. And, in some cases, even two organ sites, liver and lung can potentially be resected and long-term survival achieved. However, each patient is different. And, we have to evaluate each individual by itself. And, we should evaluate them in a multidisciplinary fashion.
Factors to consider prior to surgical treatment of the metastatic disease include, "Can the disease be resected completely?" "What has been the disease free interval?" "How is the patient doing?" "Has this patient had response to chemotherapy?" The natural history of the disease and obviously the site of the metastasis and the extent of the surgery that needs to be performed.
So, in summary, surgical resection is the primary treatment for patients with localized colorectal cancer. Bowel diversion may be temporary or perman --- permanent depending on the indication. Metastasectomy may be considered in patients without widespread disease. Each patient is different and treatment needs to be individualized in a multidisciplinary fashion. I would like to thank you for your attention and we would value your feedback. Thank you.
The Role of Surgery in the Treatment of Colorectal Cancer video
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