Colon cancer is the third most common cancer diagnosed in men and women in the United States and impacts hundreds of thousands each year and millions collectively over each decade.1 Unfortunately, it is the third leading cause of cancer-related death for men and women,2 but it is also a type of cancer which has many long-term survivors and a very good chance of long term survival if discovered early, at an “early stage.” Improving outcomes, particularly survival, is a long-term commitment for many who help diagnose and treat patients with colon cancer.
One of the most important steps in colon cancer care is accurate staging of patients at the time of diagnosis and initial surgery, or immediately following surgery when a portion of the colon that has been removed is examined by pathologists and pathologist assistants in the laboratory. Each specimen—typically a short segment of colon with attached fatty tissue containing blood vessels and lymph nodes—must be carefully examined to determine the extent of cancer involvement, particularly the depth of cancer in the mucosal lining and muscular wall of the colon and whether or not there is tumor in any surrounding lymph nodes located in what is called “pericolic fat.”
The careful post-operative pathology examination of both the tumor and lymph nodes, plus additional clinical studies with the help of gastroenterologists, radiologists, surgeons and oncologists, before, during and even after surgery, helps establish the “pathologic stage” and “clinical stage” of each patient diagnosed with colon cancer. Together this information is used by the gastroenterologist, surgeon and oncologist to determine the likelihood of recurrence and subsequent treatment as well as follow up scheduling with these clinical specialists.
Recently a technology platform called AdiPress was developed by FormaPath that can assist pathologists and pathologist’s assistants with the evaluation of tissue removed at surgery. AdiPress automates lymph node recovery and identification to help ensure that pathologists can more accurately determine the presence or absence of lymph node involvement to help ensure the most accurate cancer staging possible before long-term post-operative treatment decisions are made. The desktop sized AdiPress platform optimizes the identification of very small lymph nodes that may contain cancer but are hidden from view in the tissues surrounding the colon. It achieves this by quickly removing fat [or adipose] from tissue surrounding the colon, isolating the lymph nodes for further microscopic examination.
While only a portion of patients will need treatment after surgery, those that do will depend on the pathologist’s “lymph node count” and an accurate “nodal assessment” during dissection and continued examination under the microscope for optimal cancer staging. Typically, patients with higher stage cancer are referred to an oncologist to help guide post-operative or “adjuvant” treatment decisions, whereas those patients with very early stage colon cancer that have a low risk of recurrence may just be followed by their gastroenterologist or colon surgeon and radiologist, with no further treatment after surgery.
FormaPath’s AdiPress does not guide therapy choices or predict outcomes, but simply helps to ensure that pathologists identify each lymph node, to optimize the microscopic nodal assessment and ensure that each patient has the most accurate pathologic staging possible.
Briefly in this article, we will describe how lymph node dissection is typically performed and how FormaPath’s AdiPress can improve this process to help advance colorectal cancer care.
The initial treatment for colorectal cancer is typically based on surgical removal of the tumor, followed by post-operative “adjuvant” treatment if needed. Examination of the tumor and remaining colon tissue is a critical step to determine the “pathologic stage” or degree of cancer involvement which helps physicians make adjuvant therapy decisions to minimize the risk of recurrence.
Clinical studies have collectively shown that about 17% of patients who undergo surgery to remove all visible colorectal cancer develop recurrent disease,3 typically distant metastasis in the liver or other sites, while adjuvant treatment--when appropriate in higher stage disease--can reduce this recurrence risk by about one third, emphasizing the importance of accurate staging for colon cancer patients.
Post-operative adjuvant treatment for colorectal cancer relies on diagnostic insight from the manual dissection of lymph nodes to stage cancer patients. If cancer is found in any lymph nodes, there is a higher likelihood that the disease could spread to other organs such as the liver, hence post-operative adjuvant treatment is more likely to be considered.
Traditional manual methods of pathology dissection, with use of a scalpel and manual squeezing of pericolic fat to find nodes, samples only a portion of lymph nodes – typically the largest ones – within adjacent fatty tissue surrounding the colon. After further processing to make very thin sections of preserved tissue, pathologists examine these lymph nodes under a microscope to determine whether cancer is involving these regional lymph nodes adjacent to the colon.
Manual dissection can miss tiny lymph nodes just a few millimeters in size that may on occasion contain tumor, which could lead to an error in staging. Hence, clinical guidelines recommend pathologists find and examine at least 12 lymph nodes to minimize the risk of missing hidden foci of cancer, although very small lymph nodes may be numerous and difficult to identify. In addition, there can be variation in dissection which may result in a sampling error, or variation in the lymph node count which could affect the accuracy of staging. For the patient, this could impact decisions about their care.
How does FormaPath enable more efficient lymph node recovery and help reduce variation in dissection to aid pathologists and help improve cancer care?
Our answer to this question is AdiPress.
AdiPress is an automated lymph node dissection technology that quickly separates lymph nodes from surrounding adipose tissue. Our “Automated Compressive Filtration” process [ADF] carefully compresses the tissue specimen within a small chamber called a LymFilter removing liquified fatty fluid through a porous filter at the bottom of the container. The remaining material is a lymph node rich tissue sample captured in one or more of our LymFilters that is ready to process for microscopic analysis.
The AdiPress ADF process helps pathologists in two ways to improve their important cancer related work. First it reduces the time required to identify lymph nodes and second, it can help improve the accuracy of pathologic staging by reducing the chance of a sampling error.
The traditional manual method of lymph node dissection can take from 30 to 90 minutes or more, impacting workflow in the lab. If lymph nodes are difficult to find, pathologists may have to go back to the specimen again after their initial examination to find more nodes. The extra time spent on each case can create bottlenecks in the laboratory impacting the turn-around-time of pathology reporting for many surgical specimens including the patient sample being examined.
In contrast, the automated AdiPress platform creates standard sized lymph node samples in just a few minutes. This minimizes delays that can impact pathologist efficiency. It also reduces variation in dissection and reduces time spent on repeat dissections so that pathologists can focus on the important microscopic evaluation.
By reducing potential sampling errors, AdiPress can help improve the accuracy of pathologist’s work for many patients. While traditional methods may “sample” a portion of the pericolic lymph nodes, the ACF process allows a more thorough examination of virtually all lymph nodes in the surgical specimen.
Automated Compressive Filtration also generates lymph node tissue sections which have less fatty [adipose] tissue. Fatty tissue can be difficult to section and prepare for microscopic examination and small defects from processing can create potential errors in the microscopic evaluation of these tissue samples.
For pathologists, realizing faster turnaround times and more reliable results with the help of AdiPress has the potential to improve cancer care by helping to deliver critical information on pathologic staging that will inform adjuvant care decisions for colon cancer patients.
For most patients with colorectal cancer, the surgical removal of their colon tumor is the most important first step in their cancer care pathway and proper staging is critical to designing their overall treatment plan.
Because current pathology practices are highly reliant on labor-intensive manual methods of examination, we have created a product that is designed to facilitate faster removal of pericolic fat, enabling more reliable retrieval of lymph nodes that will be examined microscopically to determine the pathologic stage.
AdiPress has been introduced to several early partner hospitals looking to expand their laboratory capabilities and optimize workflow where they have high case volumes. Our next steps also take us into even more academic cancer centers, which treat 90% of referred colorectal cancer patients in the U.S. There, we believe AdiPress will help pathologists optimize lymph node retrieval while saving manual labor time, helping them focus on the diagnosis of cancer and serve more patients with the best results possible.
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