Maura Polansky, MS, MHPE, PA-C
Physician Assistant
Department of GI Medical Oncology
The University of Texas MD Anderson Cancer Center
Hello. I'm Maura Polansky, Physician Assistant in the Department of GI Medical Oncology at the University of Texas MD Anderson Cancer Center, where I also serve as the Director of Physician Assistant Education. This part of the course will focus on surveillance of cancer after a diagnosis of colorectal cancer.
The objectives are --- of this lesson are for the participants to be able to identify factors that increase a patient's risk of recurrence from colorectal cancer; identify practice guidelines regarding surveillance from disease; and order appropriate testing for colorectal surveillance using these established guidelines.
As we see here, stage of disease is highly predictive of five year survival after a diagnosis of colon or rectal cancer. It is important to keep in mind that data, such as this, are often obtained several years after the fact. This pa --- particular data is from patients diagnosed between 1998 and 2000 and comes from the SEER's database. As has been discussed in prior lessons with this course, there have been advances, particularly in the treatment of stage III and stage IV colon cancer, since this time. Therefore, the specific numbers may not adequately represent the advances in treatment. However, the general trends certainly remain. As one can see here, for stage II disease, when patients have a more advanced T-stage such as stage IIC, we see their survival rates at five years going down substantially, as we see for stage III disease. And certainly during this period of time, patients with IV --- stage IV disease had a less than 10 percent five year survival rate. So stage continues to be one of the most important prognostic factors in this patient population.
However, we also need to consider some other factors. We need to consider the risk period for recurrence from disease, other factors that may impact re --- recurrence risk, and the common sites of recurrence, as all of these factors play into clinical guidelines.
As we see from the data previously presented, it is now broken down over each subsequent year. And the recurrence period of time for colorectal cancer most --- most commonly is within the first five years. That is, very few patients develop recurrent disease after five years. However, the most important drop-off in survivorship occurs within the first three years. So, these are the periods of time that intensive surveillance is recommended.
With rectal cancer, not only are we concerned about the presence or the development of distant metastases, but local recurrence is a substantial problem. Local recurrence can occur within the bowel wall, that is, at the anastomosis or may occur just outside the bowel in the pelvis. And as you see here, for patients who have more advanced T-staging, such as a T4 lesion, even with no nodes involved, the local recurrence rate does increase. For stage 4 --- [excuse me] --- T4N1, it is over 10 percent and for stage T4N2, it is nearly 25 percent. So this is a real concern for this population.
As indicated previously, stage is an important factor in estimating recurrence risk. However, the grade of the tumor is an important consideration. We know that patients who have a poorly differentiated carcinoma have a much higher risk of recurrence than if the tumor is moderately or well-differentiated. Also, if on pathology review, there's the presence of lympho-vascular or perineural invasion, this increases one's risk as well. Data in the last few years has strongly indicated that nodal dissection and evaluation must be adequate to truly determine the accurate stage of a patient's cancer. So, if a patient has stage II disease, that is considered an N0 disease, it is important that at least 12 nodes were not only dissection --- dissected but evaluated by the pathologist to determine if this is truly a stage II cancer, and that nodes were not involved. And finally, the adequacy of the treatment needs to be considered. There are patients who may not receive all recommended treatment, such as someone who has substantial comorbid conditions, a patient who may have a significant postoperative or perioperative complication. And, occasionally, patients simply elect not to take all recommended treatment. So, patients who have not been adequately treated would certainly have a higher risk of recurrence.
The common sites of metastases for patients with colorectal cancer include the liver and lung, distant nodes, such as within the abdomen or retroperitoneal, and also within the intra-abdominal cavity, such as with carcinomatosis. These are the sites that are routinely imaged on surveillance. Although patients with colorectal cancer can go on to develop bone or brain metastases, these typically do not occur as the first site of metastases and, therefore, are not routinely imaged during the surveillance period.
A study published in 2005 looked at the impact of more intensive follow-up for patients compared to those who had less intensive follow-up. And there was a substantial reduction in death, up to a third of the death rate re --- was reduced if patients had a more active intensive follow-up. Patients with intensive surveillance were more likely to have surgery for curative intent, if they developed recurrent disease. And following this time, surveillance guidelines have really emphasized this intent --- intensive surveillance for patients who would be a candidate for additional treatment, should they recur.
There are three commonly reported guidelines, those of the American Society of Clinical Oncology, the National Comprehensive Cancer Network, and the MD Anderson Cancer Center Guidelines. They do vary a bit, although much of the same principles are represented in all the guidelines. And I'd like to briefly show you these guidelines.
ASCO pub --- published guidelines in 2005: They emphasize this first three-year period in --- that during this period, patients should have a history and physical exam performed every three to six months, with CEA performed every three months, and that this could be done less commonly after three years, and after five years only at the discretion of the provider. They specif --- specifically discuss that fecal occult blood testing and chest x-ray are not recommended. They do recommend annual imaging of the chest and abdomen with CT scan, and that pelvic CT be considered, particularly for those patients who've had rectal cancer, especially if they did not receive radiation therapy as part of their treatment. Colonoscopy is recommended. Typically patients with colon cancer have a colonoscopy at the time of their initial diagnosis. If they do not, it should be done in the perioperative period, and then it is recommended to be repeated at three years, and then at five years, and every five years thereafter. Proctosigmoidoscopy is recommended every six months for patients who've had rectal cancer, if they did not have prior radiation therapy.
The NCCN Guidelines distinguishes the stage of the cancer. However, their version from 2011 provided really the same guidelines for patients with stage I, II, or III disease. They recommend a clinical evaluation with history and physical every three to six months initially and then every six months for up to five years, and along with that, a CEA level for all patients, except the very earliest stage T1 patients. In addition, either CT or MRI im --- imaging for three years, to include imaging of the chest, abdomen, and pelvis. They specifically recommend against the routine use of PET-CT that we'll discuss here in a minute. And they provide a similar recommendation for colonoscopy, at one year following the initial diagnosis, then at three years, and then every five years thereafter. Their guidelines also do --- recognize the patients with stage IV disease who have no evidence of recurrent disease. So, these are patients who likely had surgery with a curative intent. And they again recommend this close period of --- of surveillance particularly with imaging every three to six months for two --- the first two years, and then every six to 12 months thereafter, for a total of five years. Again, PET scan is not recommended to be performed on a routine basis.
For rectal cancer, their guidelines are similar to that of colon cancer. The main difference is here with proctoscopy. They recommend that patients who have had a low anterior resection have a proctoscopy every six months to look for local or anastomotic recurrence.
The MD Anderson Guidelines also distinguish between the stage of the disease. But they distinguish patients who have the stage II low risk cancer versus a high risk one. So some of those features I previously mentioned, such as lympho-vascular invasion, poor differentiation, or an inadequate lymph node dissection or evaluation, could be considered high risk features. And those who have more advanced disease, such as the high risk stage II and stage III cancer patients, should have clinical evaluations every three months initially and then every six months for a total of five years. We also recommend imaging with either CT scan or MRI of the chest, abdomen, and pelvis, for the full five years. And for patients with stage IV disease, who have no active disease, again close surveillance with initial evaluation every three to four months, and then every six months thereafter, but with more frequent imaging because of the high risk of recurrence for these patients who have had metastatic disease. We also emphasize that PET scans should not be performed on a routine basis.
Our rectal cancer guidelines are also fairly similar to our colon guidelines, again, with the main emphasis being patients who've had a --- have had rectal cancer, particularly those without prior radiation therapy should have a proctosigmoidoscopy performed every six months for the first five years.
A couple of comments regarding CEA: CEA is a non-specific tumor marker. It can be elevated in a number of different cancers. It is normally less than 3 in a non-smoker, but can be higher in a smoker. So, it's important to make sure that you have an adequate history on tobacco use. It occasionally can be elevated during chemotherapy. So, again for the purpose of this discussion, we're really talking about surveillance of patients after they finish treatment. If patients have had an elevated CEA before their cancer, we would expect it to normalize after treatment, and if it later begins to rise, this may be an early indication of recurrent disease. However, a normal CEA certainly does not rule out the possibility that the patient has metastatic or recurrent disease.
As I mentioned earlier, PET scan is not routinely recommended for surveillance in colorectal cancer. There are limitations to PET scan. With PET scan, we do not use IV contrast, and there can be some limitations to detection of tumors, such as small hepatic lesions that may not be detected on a non-contrast enhanced CT, such as what would be done with PET scan. However, it does play an important role in patients who have an unexplained elevation of their CEA.
Here is an example of a PET scan that was performed in a patient with an ele --- elevated CEA, but who had no clear evidence of disease on CT. Here we see an FDG avid adrenal gland just above the kidney that represents an area of metastases. On the imaging, on routine imaging, it was only seen as a slightly enlarged adrenal gland, but no clear tumor was present, but that's clearly seen here on the PET scan.
A similar case, and in this case, there is an FDG avid tumor at the junction of the second and third portion of the duodenum as well as an adjacent lymph node. And these were not detected on other imaging modalities. So, the PET scan showed an important role in these patients.
So, guidelines both by the NCCN and by MD Anderson discuss the importance of CE --- of PET scan for patients who had an elevated CEA. So, if a patient has a high CEA, it's important to review the history and physical exam to determine if there is any localizing signs or symptoms to suggest a site of metastases. CT or MRI imaging should be done as the first imaging modality. And also, if patients have not had a routine colonoscopy, this should be performed, both to look for the possibility of a recurrence within the bowel as well as new lesions within the colon. If all of these are negative, then PET-CT may play an important role and should be considered. If the PET-CT is again read as negative, then it is recommended that these patients return for re-evaluation in six mon --- excuse me, in three months, that you don't revert to the regular surveillance guidelines, that you see these patients back fairly soon for re-imaging.
So in summary, the greatest risk of recurrence from colon and rectal cancer is within the first five years following treatment. Common sites of recurrence include the liver, lung, lymph nodes, and intra-abdominal sites as well as within the bowel, particularly for those patients with rectal cancer. And clinic --- practice guidelines, such as the NCCN and MD Anderson Guidelines are available to clinicians to guide the surveillance period. This completes this section of the course. We hope that you have found this material helpful. Please feel free to contact us with your feedback or suggestions for additional content. Thank you.
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