The Role of Pathology in Colon Cancer Screening
Colon cancer is the third most common cancer in both men and women. In 2015 there will be an estimated 93,090 new cases of colon cancer and 39,610 new cases of rectal cancer. It is the second leading cause of cancer related deaths for both men and women. In 2015 there will be an expected 49,700 deaths due to colorectal cancer. Beginning at age 50, those with an average risk of colon cancer should begin screening with either a colonoscopy (every 10 years) or a fecal occult blood test (yearly).
During a colonoscopy, the gastroenterologist will examine the entire length of the colon, and often a portion of the small intestine (ileum). Any abnormalities, such as inflammatory changes, polyps or other masses will be biopsied. In this technique, a small portion of tissue will be cut from the surface of the intestine lining. The specimen is then sent to the pathology lab.
Upon reaching the lab, the tissue is carefully examined and described by a pathologist or pathologist assistant.
The biopsy is placed into a cassette then processed in an instrument to prepare it for cutting.
Next, the specimen is embedded into paraffin, cut and placed on a slide.
This is stained, cover slipped and delivered to the pathologist.
A pathologist will then examine the specimen under a microscope and make a diagnosis.
Often in challenging cases, it will be shared with colleagues for consultation. Additional slides and/or stains may be performed to clarify any uncertainty in order to reach the most accurate and precise diagnosis. Consultation is also available from pathologists who are experts in gastrointestinal (GI) pathology. Often the pathologist will discuss the case with the gastroenterologist, particularly in cases where clinical correlation is needed and may even review endoscopic images. A report is then prepared and finalized.
Different types of polyps are illustrated below.
The pathologist’s involvement does not end here. Clinicians may call for an explanation if anything is unclear, or the pathologist may call proactively to prepare them for what to expect.
Your pathologist will stay with you throughout your care. They will likely participate in a multi-disciplinary conference with other specialists where all current cases are discussed. If additional procedures are performed, the specimens will be compared with prior material.
The pathologist will often perform testing on the tumor for genetic mutations. Again, this provides crucial information in order to select the right chemotherapy regimen. If a cancer is found, the tumor can be tested for whether the patient has an inherited cancer syndrome (i.e. Lynch syndrome). This will provide crucial information for both the patient and family members on future screening recommendations.
Patients can take steps to help ensure their GI biopsy is read accurately:
Inquire about the pathology laboratory that will examine your tissue sample. Is the laboratory accredited? The CAP accredits more than 7,600 laboratories worldwide and provides an online directory for patients.
Make sure the pathologists who are examining your tissue samples are board-certified.
Find out if your hospital has a multidisciplinary GI conference. This is a team of physicians and other health care professionals that meets regularly to discuss diagnosis and management of patients with GI disease, guaranteeing more consultation about the best approach for your care.
If your hospital doesn’t have a multidisciplinary GI conference, consider getting a second opinion. Second opinions are always welcome. Have your doctor send the biopsy slides to another laboratory and request they be read by a pathologist who specializes in GI pathology. Insurance typically covers second opinions.
Seek out accurate and credible resources to help you understand your pathology report and diagnosis, such as the CAP’s resource, “How to Read Your Pathology Report.” Most accredited surgical pathology laboratories include second opinion slide review as part of their quality management program. Ask about this.
The pathologist is a vital member of the health care team. You know your other doctors. Now meet us.