Moving the Needle on Colorectal Cancer Pathology


Carcinoma of the colon or rectum (colorectal cancer [CRC]) is a common and lethal disease. Approximately 134,490 new cases are diagnosed each year in the United States. Annually, approximately 49,700 Americans die of CRC, accounting for 8 percent of all cancer deaths. The Michigan Surgical Quality Collaborative recognizes the importance by having a dedicated project specific to improving the quality of care for patients with colorectal cancer. For better local control and survival, the surgical technique of total mesorectal excision (TME) is widely accepted as the gold standard for rectal cancer treatment.

Through the CRC project, the MSQC collects data specific to the patient's preoperative workup, surgical resection, and pathology measures to drive quality improvement. This includes documentation of total mesorectal excision, mesorectal excision grade and total number of lymph nodes examined. While the quality of the surgical resection is a predictor of patient prognosis, the pathologist's role in providing an accurate and complete pathology report assists the treatment team in further understanding and treating the patient's cancer after surgery. Pathological indicators of quality for rectal cancer include the integrity of the mesorectum (TME grade), negative margins of the resection, and adequate lymph node examination (≥12).

Total Mesorectal Excision

Integrity of the mesorectum correlates with the rate of local and distant cancer recurrence. When the plane of dissection occurs at the mesorectal plane (meaning the entire mesorectum is removed), the chance of recurrence is decreased and the chance of having a negative circumferential margin is increased. The envelope around the rectum has to be removed intact. If not removed intact, malignant cells are more likely to be left behind. It has been shown that when an institution adopts the TME grading system, there seems to be a positive feedback mechanism which improves surgeon's technique over time. A valuable tip from our experts: When at all possible, the surgeon should not open the TME specimen in the OR. If a specimen is opened prior to the pathologist being able review the integrity and grade the specimen, this may result in the specimen not being graded. If the surgeon would like to view the specimen open, the best practice would be to view the specimen in the pathology lab to protect the integrity of the specimen.

Circumferential margin (CRM) of the TME is a strong predictor of local and overall recurrence. Previously it was thought that the distal margin was the most important, however, we now know the CRM is actually the most important. There are several ways in which the tumor may reach the CRM: direct tumor extension, continuous/discontinuous foci of vascular invasion, and/or positive lymph node at CRM. Some factors associated with positive CRM include advanced tumor necrosis, large tumor size, infiltrative margin, poor differentiation, vascular invasion, or poor mesorectal quality (that is, poor surgical technique).

Achieving an adequate lymph node examination requires collaboration between the surgeon and the pathologist. The number of lymph nodes dissected from a colorectal specimen influences prognosis; multiple studies have shown improved survival when more nodes are examined. Reasons for this could include more accurate staging, better immune response, and/or optimal quality of care. Pathologists need to be aware of the importance of adequate lymph node dissection from the specimen and using ancillary techniques if necessary. For cases in which a patient has received preoperative chemoradiation therapy, this can decrease the number of lymph nodes the patient has. Using an enhanced visualization technique has been found to increase the lymph node yield and more importantly, a higher incidence of finding metastatic cancer. Lymph node examination varies more with pathologists than with surgeons. For example, at MSQC, we learned about techniques from three hospitals with varying site characteristics all using different techniques. Each technique has its own advantages and disadvantages. While there are many techniques in practice, it is important that the pathologist be satisfied and confident in the number of lymph nodes examined for quality of care. Our MSQC quality measure defines good performance as "at least 12 nodes examined”.

The surgical pathology report is the final product of the diagnostic process. It should be standardized, systematic, and consistent. The power of a multidisciplinary team that includes the surgeon and pathologist can improve the quality of the TME, which is crucial to a patient's prognosis and survival of rectal cancer. Many postoperative decisions are made by what pathologists see. Having this collaborative multidisciplinary relationship can improve the selection of patients for neoadjuvant treatments, comparison of findings, and feedback to surgeons by pathologists on quality of surgery. While a multidisciplinary team may not be possible at each hospital, at the very least, the surgeon and pathologist partnership is integral to high quality rectal cancer care.


Some tips from our experts on how to start a TME grading program:

  • It starts with a surgeon and pathologist to champion the project. Determine the current state of the practice at your hospital. Is there any kind of TME grading at your hospital? What is the process? Who is involved, etc? For surgeons looking to implement this project, showing the clinical importance of TME grading for quality of patient care can allow for the pathologist to understand the need to adjust practice.
  • When first developing a TME grading program, it is best to have the surgeon and pathologist review the integrity of the specimen together. Some have reported taking pictures of the specimen for review later at a multidisciplinary meeting. The importance of working with other involved clinicians when conducting grading can’t be stressed enough.
  • Instituting a checklist for cancer specimens can help to increase reporting of the measures. Reporting lines can be removed if not applicable. The pathology champion can review the pathology reports to see what was reported or removed, provide feedback and add an addendum in order to compile a complete  pathology report.

MSQC hospitals can voluntarily participate in a QI and research project designed to improve TME grade at their hospital.



College of American Pathologists (CAP) protocol for the examination of specimens from patients with primary carcinoma of the colon and rectum- See page 17

National Accreditation Program for Rectal Cancer Standards Manual (American College of Surgeons Commission on Cancer) 2017 Edition- see page 40

Cancer Care Ontario and the Canadian Cancer Society: MRI Rectal Staging Template (2015)

Cancer Care Ontario and the Canadian Cancer Society: User’s Guide for the Synoptic MRI Report for Pre-Operative Staging of Rectal Cancer (2015)

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