LAR or sigmoid resection?

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Lilianacb
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Joined: Wed Apr 11, 2018 2:58 pm

LAR or sigmoid resection?

Postby Lilianacb » Wed Apr 11, 2018 5:03 pm

Hello,
First I would like to thank you all for contributing to this blog and helping others. My mom had a colonoscopy and the gastroentelogist found a tumor at 20 cm from anal verge. Then we went to the colorectal surgeon who rendered another colonoscopy confirming the same results, the biopsy showed severe dysplasia. Then lab results showed a CEA of 1.4 and ct scan showed clear lungs and other organs nearby, however the lymph nodes in the area of the tumor are imflamated. The surgeon thinks it is cancer and suggested a Lower anterior resection. After looking in several websites, I noticed that 20 cm from anal verge is the sigmoid colon, not the rectum. Then why a LAR was suggested and not a sigmoid resection? I am really worried because I have read was the LAR syndrome after that procedure. Or is it a LAR and a sigmoid resection the same thing? Thank you very much!

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O Stoma Mia
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Re: LAR or sigmoid resection?

Postby O Stoma Mia » Thu Apr 12, 2018 3:34 am

Lilianacb wrote:...The surgeon thinks it is cancer and suggested a Lower anterior resection. After looking in several websites, I noticed that 20 cm from anal verge is the sigmoid colon, not the rectum. Then why a LAR was suggested and not a sigmoid resection?...

Image

I think the answer to your question probably revolves around the definition of “Complete Mesocolic Excision (CME)”, which is the type of conservative surgery they would want to do if the tumor is clearly located in the sigmoid colon area . I think that this type of surgery is usually performed using a sigmoid resection or a left-hemicolectomy. On the other hand, the removal of a tumor in the mid or upper rectum would involve what is called Total Mesorectal Excision (TME), and is usually performed using the LAR procedure – either open or laparoscopic

But it may be the case that the tumor is located low down in the sigmoid area close to the rectosigmoid junction, in which case the situation is a bit more complicated.

As discussed in the article below, the decision really depends on anatomy and where, exactly, the tumor is located, and where the nearby relevant lymph node ganglia are located.

I think that the overall constraints are probably something like the following:

They will want to remove the tumor with plenty of margin both above and below the tumor. If your tumor is located at 20cm above the anal verge, then the lower cut might be at around 15cm from the anal verge. The lower cut has to be well below where the tumor is located so that there is no chance that the tumor margin will be pierced by the scalpel. But the lower cut also has to be below where the relevant lymph nodes are located because they will want to remove all of the “at-risk” lymph nodes at the same time. Depending on where the tumor is located and what its drainage pattern is, the relevant lymph node ganglia might be high up or low down with respect to the tumor. This is what the surgeon has to figure out by using his knowledge of anatomy.

So, it might turn out that the best place to make the lower cut would actually be in the upper rectum area, even though the tumor itself is in the lower sigmoid area. This might be why the surgeon said “LAR” rather than “left hemi-colectomy”or “sigmoid resection," because LAR is typically used whenever any part of the rectum is going to be removed.

Ï think you would have to talk to the surgeon to ask what considerations are relevant for his decision about the type of surgery to use.

I don’t know the answer to your question. Maybe you can get some additional perspective by reading articles like the one below.

Complete mesocolic excision: Lessons from anatomy translating to better oncologic outcome
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4789608/

In any event,whatever the situation might be it is very important to have an experienced, Board-Certified colorectal surgeon doing the surgery, especially if the lower cut is likely to be in the upper-rectum area, since this is where some of the important muscles and control mechanisms for bowel movement are located, and which must be preserved if the patient hopes to have normal bowel movements after the surgery is finished.

Lilianacb
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Joined: Wed Apr 11, 2018 2:58 pm

Re: LAR or sigmoid resection?

Postby Lilianacb » Thu Apr 12, 2018 7:42 pm

Thank you very much for your reply! The information you have provided is extremely helpful!!!

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O Stoma Mia
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Re: LAR or sigmoid resection?

Postby O Stoma Mia » Fri Apr 13, 2018 2:57 am

I think that if you ask your surgeon where he intends to make the lower cut, then you will have a better idea of the extent of LAR Syndrome that might occur.

For a lower cut in the upper rectum, I think that the main problem would be possible damage to some of the muscles and nerves involved in bowel movements. In particular, there are the levitor ani and pubis recti muscles which might be damaged when the surgeon is trying to remove the lymph nodes.

Here is a diagram that shows how close the levitor ani muscles are to to the area of the mesorectum where the lymph nodes are located.

Image

If these muscles are removed or damaged, then there may be problems in completely emptying the bowel, because these are the muscles that help squeeze the rectum during bowel movement to force the rectum to empty itself.

There have also been some discussions of this in previous topics here:

https://coloncancersupport.colonclub.com/viewtopic.php?f=1&t=56911&p=450129#p450129

menreeq
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Joined: Fri Jun 30, 2017 10:26 am

Re: LAR or sigmoid resection?

Postby menreeq » Sun Apr 22, 2018 12:24 am

My tumor was also rectosigmoid and figuring out whether it was rectal or colon cancer was key. I looked up a lot of GU, CRS and radiology literature, and distance from the anal verge can vary. I think mine was 15 cm but it was treated as colon. If you’re at the border, it makes it tough. I had a rectal MRI as well but ultimately the decision was made by my board-certified colorectal surgeon.

My suggestion would be to get at least two opinions at academic cancer centers.

Good luck.
Stage IIA rectosigmoid CC (T3N0M0)
Dx 6/5/17 @age 41, mom to 5 & 2yo girls
Workup: c-scope, EUS, rectal MRI, CT C/A/P
AdenoCA 5.5cm, WHO Grade 2, 0/22 LN, no distant mets
CEA 1.9 (6/5/17), 0.8 (2/28/18)
No lymphovasc/perineural invasion, clear margins
MSI intact, OncotypeDx RS 7
Lap sig colectomy 6/23/17, no ileo/colostomy
Genetics counseling negative for mutations, 4 VUS
Xeloda monotherapy 8/13/17-1/22/18
PET/CT 3/21/18 NED


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