The scientific and clinical merits of COLOGIC are supported by significant published research. Scientific support continues to expand.
Currently, there is no study to directly compare fecal tests (FIT and FOBT) with COLOGIC. The data provided below outlines the performance of each test on its own merits with references.
Screening Tests – Comparing Current Common Testing Modalities - Colorectal Cancer
|COLOGIC**||Fecal Occult Blood Test*||Fecal Immunochemical Test*|
|Sensitivity||86% (80 to 100%)||35% (23 to 53%)||61% (30 to 88%)|
|Specificity||90% (90 to 98%)||87% (59 to 99%)||92% (65 to 98%)|
FOBT – Fecal Occult Blood Test.
FIT – Fecal Immunochemical Test.
Sensitivity – Ability of the test to correctly identify subjects with disease.
Specificity – Ability of the test to correctly identify subjects without disease.
*As reported in the 2009 Canadian Agency for Drugs and Technologies in Health (CADTH) Health Technology Assessment of FIT and FOBT (www.cadth.ca/index.php/en/publication/928). Figures are averages across all included studies as presented in Appendix 3, Tables 1 and 2.
**Based on publications Ritchie et al. BMC Medicine 2010, 8:13; Ritchie et. al. BMC Gastroenterology, 2010, 10:140; Ritchie et al. Journal of Experimental & Clinical Cancer Research 2011, 30:59: Ritchie et al. International Journal of Cancer, 2012, doi: 10.1002/ijc.27673. Figures are averages across all included studies.
Phenomenome Discoveries pioneered technologies that allow for the accurate and simultaneous detection of thousands of metabolites in biological samples. This appropriately named "non-targeted metabolic profiling" technology was performed on blood serum samples from patients with CRC and compared to the profiles of healthy cancer-free subjects. Among the thousands of metabolites detected, a small group of approximately 30 were shown to be significantly lower in the serum of CRC patients relative to healthy subjects. This discovery process was repeated in three independent sets of samples, with the same results every time.
Further research showed that the metabolites had not been previously identified or reported, and therefore represented a new biological finding. Preliminary structural investigation using mass spectrometry and NMR showed that the molecules consisted of 28 or more carbons, and resembled very long-chain fatty acids (similar to DHA or EPA but larger). Due to the presence of the carboxylic acid chemical group on each of the metabolites, they were collectively named gastrointestinal tract acids (GTAs). The proper scientific name, used in this paper, is hydroxylated polyunsaturated ultra long-chain fatty acids (hPULCFAs). Numbers appearing after the acronyms simply refer to the molecular weights of individual species.
A simpler method to detect GTAs was then created using a more conventional approach based on tandem mass spectrometry, which allowed for the specific determination of single GTA species in a highly accurate fashion. This method was used to test two further independent populations. Consistent with the previous results, GTA levels were observed to be significantly lower in the serum of CRC patients compared to the healthy controls. On average, CRC patients showed at least a 50% reduction in the circulating levels compared to controls, with little to no correlation between disease stage and magnitude of the reduction. GTA levels could discriminate CRC patients from controls with 91% accuracy based on several receiver-operator characteristic (ROC) curve areas.
In total, five independent populations comprising nearly 450 samples from different geographic locations and different ethnic background showed consistent results. The paper concludes with a discussion on the possible connection to lipids involved in controlling inflammation, the possible role of these novel metabolites in the disease process, and the implications of CRC screening based on GTA testing.
View full paper: BMC Medicine 2010, 8.
This paper reports the results of GTA levels in six separate populations of samples. The objectives of this paper were to (a) define GTA levels in a large age-distribution of the general population, (b) investigate intra-individual GTA fluctuations, (c) measure GTA levels following surgical tumor removal and conventional therapy, and (d) model the outcomes of longitudinally screening a given population over time using GTA testing versus fecal blood testing.
The key findings pertaining to each objective were:
(a) There is an inverse-association between age and GTA level in the general population. As age increased, the levels of GTAs decreased. This was determined by a random sampling of nearly 1,000 Saskatchewan residents. Reduced GTA levels with age correlated with the increased incidence of CRC with age, leading the authors to comment on the possible causative link between GTA decline and CRC risk.
(b) GTA levels within the same subjects over time appear to be very stable. GTA levels were measured in both disease-free and stage IV CRC patients for up to 90 and 63 weeks, respectively, with little to no fluctuations over time in either group. The results suggest that the GTA metabolic system is relatively homeostatic, and likely shows a slow but steady decline with age within the general population.
(c) Low GTA levels are not restored following surgical removal of tumours and do not change with respect to combination chemo/radiation therapy. This was demonstrated among three independent populations and confirmed the prior hypothesis that low GTA levels in CRC patients are NOT the result of tumour burden. In light of the age-associated decline, this strongly suggests that GTAs become reduced prior to the appearance of clinical symptoms and may indeed represent one of the earliest possible detectable risk factors for the disease.
(d) Although there is a GTA-age association, there are only 0.65% more subjects year-by-year with low GTA levels. Therefore, when a person is tested and has normal GTA levels, there is only a 0.65% probability that, if tested the following year, he/she will have low levels. This is a critical point because it means that although 10 to 20 percent of a population aged 40 to 80 will show low GTA levels on a first test, subsequent testing in those subjects with normal GTA levels will result in a positivity rate of only 0.65% annually. Since other CRC screening tests do not behave this way, they will generate approximately the same positivity rates in the same population year after year. As shown in the paper and in the graph, the number of required follow-up colonoscopies required for a population as it ages from under 50 to 80 is five times lower with GTA-based screening versus FIT, for example. The results also showed that more CRC cases would be detected with GTA testing during this time.
Collectively, the results further support the hypothesis that GTAs do not become low as a result of cancer, but rather that they decline prior to the start of cancer. A possible causal role of low GTAs in promoting cancer is established, which sets the framework for the next paper in the series which begins to address the biological activity of GTAs.
View full paper: BMC Gastroenterology 2010, 10:140.
This paper describes the results of experiments which show that GTA fatty acid metabolites present in human blood can protect against inflammation and inhibit of cellular proliferation. GTA metabolites are previously described hydroxylated ultra-long chain fatty acids which are abnormally low in the serum of colorectal cancer patients. The experiments performed in this study involved the in vitro treatment of several cell lines with human blood extracts that were enriched for specific GTA fatty acids, followed by various biological assays to measure the effect of the treatments.
Compared to control extracts containing no GTAs, extracts with high levels of GTAs had two important effects:
1. Reduction in the rate of cell growth. A hallmark feature of cancerous cells is the inability to control cell growth. Human colon cancer and breast cancer cells, when treated with GTAs, showed a reduction in the rate of cell growth. Specific experiments were performed to show that the mechanism of the inhibitory growth effect involved the induction of apoptosis, a process whereby cells induce their own destruction. Apoptosis is critical so that damaged cells do not divide uncontrollably, potentially leading to the development of cancer. The results therefore suggest that GTAs play a role in inducing apoptosis, and therefore may be important for preventing the uncontrolled division of cells as seen in cancer.
2. Protection against inflammation. Inflammation is an immunological response involving the localization of white blood cells and other molecules to a site of injury or stimulus. Inflammation is a key underlying component to many acute and chronic diseases including cancer. The potential for GTAs to protect against inflammation was suspected prior to these studies because of their structural resemblance to other fatty acids that also have anti-inflammatory activity. To show that GTAs have the ability to protect against inflammation, cells were pre-treated with GTAs and then with chemical agents that induce a massive inflammatory state. In cells pre-treated with GTAs, the induction of numerous pro-inflammatory markers (including NF-kappa-B, TNF-alpha, interleukin 1-beta, cyclo-oxygenase 2 and inducible nitric oxide synthase) were blocked compared to cells that were not pre-treated with GTAs. In concert with an observed stabilization of a protein (I-kappa-B-alpha) that sequesters inflammation promoting compounds (NF-kappa-B), the results suggest that GTAs might mediate their anti-inflammatory effect by disrupting signalling pathways (mainly the I-kappa-B-alpha-NF-kappa-B signalling axis) which lead to reduced expression of numerous pro-inflammatory molecules.
The paper concludes with a detailed discussion that unifies several key processes by which the age-related reduction in GTAs could be a central component to the increase in chronic-inflammation with age. These include the well-studied role of NF-kappa-B in regulating cell growth and inflammation, as well as its role in ageing. A possible involvement of the gut microbiome is also hypothesized.
View full paper: Journal of Experimental & Clinical Cancer Research 2011, 30:59.
This paper reports the results of a prospective clinical trial which enrolled 5000 subjects undergoing colonoscopy on a first-come first-serve basis at two hospitals, and 1000 random samples representative of the general Saskatchewan population. There was no exclusion based on prior GI symptoms or CRC risk. Serum samples were collected from consenting subjects, and GTA-446 levels determined using tandem mass spectrometry.
An abnormally low GTA-446 level was defined as any concentration falling within the lowest tenth percentile of a low age-risk population. The number of subjects in several subsets of the population with GTA-446 levels below this cut-off was then determined. The primary findings, as shown in detail in Table 3 of the paper, were the following:
(a) Consistent with previous results, the number of subjects with low GTA-446 levels increased with age.
(b) 87% of newly diagnosed CRC patients with stage 0-II and 85% of stage III/IV showed low GTA-446 levels.
(c) The CRC incidence rate in subjects with low serum GTA-446 levels was 2.4 times higher than in subjects with hereditary risk and 1.8 times higher than in subjects with overt GI symptoms (see figure below).
(d) CRC incidence was observed to significantly increase with age in all subjects and in subjects with low GTA-446 levels, but not in subjects with normal serum GTA-446 levels.
The findings showed that compared to the presence of overt GI symptomology or hereditary risk, low GTA-446 levels represented the highest risk of CRC. The discussion primarily focuses on the fact that despite a lot of effort, current CRC screening compliance based on colonoscopy and FIT is low. The most effective CRC screening program will be one which has the greatest impact on health outcome in terms of both mortality and cost. Increased early detection, which is the goal of any screening program, is ultimately defined by a combination of the test compliance with early-stage test sensitivity. The findings from this study (as well as the other studies) indicate that the measurement of GTA-446 levels for population-wide CRC screening would meet these two criteria.
The ultimate purpose of COLOGIC is to help enable the physician to monitor the patient's CRC risk over the course of their screening lifetime (i.e. 50+ for now). COLOGIC has significant clinical support, BUT it is a new test. Phenomenome Discoveries Inc. has robustly determined the minimum GTA level that is protective (i.e. people with GTA levels above 0.35 have a 99.95% NPV). In addition, we (i.e. the entire scientific community) also know that CRC risk in the general population is heavily influenced by lifestyle. What none of us know is, at the single patient level (i.e. n=1), how environmental factors influence GTA levels or how the awareness of CRC risk will influence a patient’s dietary/lifestyle choices. Therefore, it is very important to monitor the change in GTA levels over time, especially in the deficient population.
In subjects who test negative, (i.e., they have normal GTA levels), there is a 1.5 to 2% likelihood that they will test positive two years from now. This was based on large cross-sectional data. PDI has published results in healthy subjects for about 24 months with monthly samplings showing little to no decline (thus suggesting the decline is probably slow and steady). However, given that the mean sojourn time of most colon cancers (the time from early stage O to clinical burden) can be two to three years, the possibility that a person could undergo a rapid GTA decline followed by aggressive disease cannot be excluded.
Two-year biennial screening is also consistent with other screening guidelines. The test result is set up to be yes/no, with little subjectivity in interpretation required. The test result will also include a value and a range. Therefore, if a person’s result is just above the cut-off, it highly warrants a second test two years later.
For subjects who test positive, it is likely they will remain positive (i.e., have low GTA levels). However, to reduce the likelihood of a preceding test being a false positive due to a possible dietary or lifestyle factors (especially given that this is a newly discovered metabolic system in the human body), it would be worthwhile to retest the person in two years.
As more data becomes available over time, it should be possible to refine the frequency of testing. There is no risk in repeat testing and it should increase confidence for the clinician and patient.
Staging describes the extent of the cancer based on how many layers of the bowel wall are affected, whether lymph nodes are involved, and if there is spread to other organs. For colorectal cancer, staging often can't be completed until after surgery to remove the primary tumour along with surrounding tissue (containing lymph nodes), and possibly lesions found on other organs. A pathologist studies the surgical specimen(s) to determine the stage. The most frequently used, and most precise staging system for colorectal cancer, is the TNM system. TNM stands for Tumour Nodes Metastases, and the system describes the extent of each using numbers; the higher the number, the more of the element that is affected:
This cancer is confined to innermost layer of the colon or rectum.
There is no spread to lymph nodes.
This cancer has grown through the first few layers of the colon or rectum.
Cancer is found in 1-3 lymph nodes.
The cancer has grown into the thick muscular layer of the colon or rectum.
Cancer is found in four or more lymph nodes.
The cancer has grown though the entire colon or rectum wall.
There is no spread of cancer to distant organ(s).
The cancer has grown through the entire colon or rectum wall and into nearby tissue or organs.
Cancer is found in distant organ(s).
After each element has been determined, they are combined to form an overall stage of the cancer in roman numerals, the higher the number, the more advanced the cancer. This is generally how the cancer is referred to between doctor and patient:
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