Introducing CancerSEEK

A blood test, CancerSEEK, has shown some efficacy in detecting a variety of cancer types, including some for which screening is currently difficult or impossible (although stomach, which is listed by them in that category, can be interrogated by upper GI endoscopy or barium imaging).  Interesting, some data can be obtained from this blood test to actually localize where the tumor is to a small number of anatomic locations for the types of cancer studied.  This is a promising diagnostic tool.  Abstract:

Earlier detection is key to reducing cancer deaths. Here we describe a blood test that can detect eight common cancer types through assessment of the levels of circulating proteins and mutations in cell-free DNA. We applied this test, called CancerSEEK, to 1,005 patients with non-metastatic, clinically detected cancers of the ovary, liver, stomach, pancreas, esophagus, colorectum, lung, or breast. CancerSEEK tests were positive in a median of 70% of the eight cancer types. The sensitivities ranged from 69% to 98% for the detection of five cancer types (ovary, liver, stomach, pancreas, and esophagus) for which there are no screening tests available for average-risk individuals. The specificity of CancerSEEK was > 99%: only 7 of 812 healthy controls scored positive. In addition, CancerSEEK localized the cancer to a small number of anatomic sites in a median of 83% of the patients.

Another Possible Non-Invasive CRC Screen?

Under study:

Background - Colorectal cancer is one of the main cause of cancer in the world. Colonoscopy is the best screen method, however the compliance is less than 50%. Quantification of human DNA (hDNA) in the feces may be a possible screen non-invasive method that is a consequence of the high proliferation and exfoliation of cancer cells.

Objective - To quantify the human DNA in the stools of patients with colorectal cancer or polyps.

Methods - Fifty patients with CRC, 26 polyps and 53 with normal colonoscopy were included. Total and human DNA were analyzed from the frozen stools.

Results - An increased concentration of hDNA in the stools was observed in colorectal cancer patients compared to controls and polyps. Tumors localized in the left side of the colon had higher concentrations of hDNA. There were no differences between polyps and controls. A cut off of 0.87 ng/mL of human DNA was determined for colorectal cancer patients by the ROC curve, with a sensitivity of 66% and a specificity of 86.8%. For polyps the cut off was 0.41, the sensitivity was 41% and the specificity 77.4%.

Conclusion - A higher concentration of hDNA had been found in colorectal cancer patients. The quantification of hDNA from the stools can be a trial method for the diagnosis of colorectal cancer.

Gut Microbiota As A Colorectal Cancer Screening Tool

A proposed method for non-invasive colorectal cancer screening is to test the gut microbiota from stool samples; this is interesting, but obviously requires more development.  One possibility is that a combination of different non-invasive screening tools - fecal occult blood, gene testing from fecal matter, microbiota together with risk factors, etc. - can together provide sufficient accuracy and precision to be an effective screening combination.  Or else, "bite the bullet" and get the colonoscopy.  The abstract of this paper is reproduced below.

Recent studies have suggested that the gut microbiome may be an important factor in the development of colorectal cancer. Abnormalities in the gut microbiome have been reported in patients with colorectal cancer; however, this microbial community has not been explored as a potential screen for early-stage disease. We characterized the gut microbiome in patients from three clinical groups representing the stages of colorectal cancer development: healthy, adenoma, and carcinoma. Analysis of the gut microbiome from stool samples revealed both an enrichment and depletion of several bacterial populations associated with adenomas and carcinomas. Combined with known clinical risk factors of colorectal cancer (e.g., BMI, age, race), data from the gut microbiome significantly improved the ability to differentiate between healthy, adenoma, and carcinoma clinical groups relative to risk factors alone. Using Bayesian methods, we determined that using gut microbiome data as a screening tool improved the pretest to posttest probability of adenoma more than 50-fold. For example, the pretest probability in a 65-year-old was 0.17% and, after using the microbiome data, this increased to 10.67% (1 in 9 chance of having an adenoma). Taken together, the results of our study demonstrate the feasibility of using the composition of the gut microbiome to detect the presence of precancerous and cancerous lesions. Furthermore, these results support the need for more cross-sectional studies with diverse populations and linkage to other stool markers, dietary data, and personal health information. Cancer Prev Res; 1–10. ©2014 AACR.

Mike's Colonoscopy

Screening for colorectal cancer, a major cause of morbidity and mortality in developed counties is important. It was time for me to get my colonoscopy, and after some procrastination, I followed in the footsteps of Larry the Cable Guy and Mark Cuban and got it done.

The procedure itself was uneventful, and much of my anxiety and fear about the procedure was, in my case, unwarranted. I admit that the prep was not pleasant. I didn’t mind so much the day before, with the liquid diet. I also didn’t mind too much being up half the night going to the bathroom, all the endless toilet visits. I had a sigmoidoscopy done years before, so I expected that.

The worst part for me was the repulsive taste of the laxative solution (in my case, Moviprep). It was difficult getting down and difficult keeping down. Following the suggestions of the hospital gastroenterology unit, I added Crystal Light to the solution; in retrospect, that may have been a mistake. The sickeningly sweet taste may have been a combination of the prep itself (which tastes bad) and the concentrated added lemonade flavoring. It may be a good idea to make sure the additive is necessary before using it. If you think you can stomach the laxative alone (some people can and some cannot), then that might be the more prudent approach.

There are other prep solutions of course, and some people use the pill option. But I have read that, in some cases, the pill options and related prep types can cause kidney damage, so I went for the more standard prep options. Keep in mind that these preps, even with insurance, are somewhat expensive, but are necessary (in some cases, patients are told they can use a cheaper MiraLAX-Gatorade prep option).

So, based on my experience, I agree with Larry and Mark and advise to follow your physician’s recommendations about getting your screening done. There is a low risk of complications from the procedure, but in the hands of a capable and experienced endoscopist, these risks will be very low – certainly lower than the risk of cancer.

For those more interested in technical details and some recent advancements in technique, I would recommend to watch YouTube videos from a well-known MD Anderson gastroenterologist, Dr. Raju, who has helped to refine advanced endoscopic techniques that I hope will one day be the standard of care here in the USA (and elsewhere).

Actionable: Follow the advice of your physician, get screened for colorectal cancer when appropriate, utilizing whatever method you and your physician agree on.

People Do Not Want To Know Their Cancer Risk?

Here is a study that suggests that many people don’t want to know their personal cancer risk; reasons for this are given as well.

Based on our representative sample, 39% of the population indicated that they agreed or strongly agreed that they would "rather not know [their] chance of getting cancer." This preference was stronger among older participants, female participants, and participants with lower levels of education. Preferring to avoid cancer risk information was stronger among participants who agreed with the beliefs that everything causes cancer, that there's not much one can do to prevent cancer, and that there are too many recommendations to follow. Finally, the preference to avoid cancer risk information was associated with lower levels of screening for colon cancer.

Note several things here. First, in certain populations at higher risk for cancer (older, less educated), there is an increased prevalence of the “I rather would not know” mentality.  We also see the cost of the media distorting and exaggerating various studies that come out – some of them occasionally contradictory – about cancer risk and health.

The constant drumbeat of scare articles about various things that may cause cancer is not helpful. There are some well-documented and important factors: smoking, obesity, diet, radon, certain viruses – and these should be publicized MORE. On the other hand, the constant stream of poorly documented speculation, often refuted by new studies, does more harm than good. It is like the “boy who cried wolf” story, straining credibility, and also giving the impression that since every daily activity causes cancer, then, “what can you do?” Of course, if new cancer-causing agents are discovered and are well-documented, then this needs to be publicized. But ill-documented sensationalism for the sake of “page hits” is irresponsible.

Related to this is the confusion of recommendations, which mirror in their complexity and contradictions the endless stories of new and often esoteric causes of cancer

Then there is the attitude of “there’s not much I can do to prevent cancer” which is in part due to recent articles claiming that “most cancers are due to genetic bad luck.”

What happens is that people skip over the part about screening, they skip over the part about those cancers that are affected by environmental factors (and they will not be aware of flaws in the interpretation of the study), and they will shrug their shoulders, smoke that cigarette while eating a deep-fried Twinkie and trust in their “good luck.” This is of course inconsistent with the “everything in the environment causes cancer” idea, but then this is the problem – extremes of opinion in one direction or another.

This has real-life consequences, such as lower levels of colon cancer screening, and, likely, continued bad health habits. And I believe this not only applies to cancer, but other problems as well: obesity, diabetes, etc. Human nature is to avoid thinking about potential bad news and to avoid hearing things that may be unpleasant or which go against currently held beliefs or which might result in undesired changes in habits (change in diet, exercise, etc.). Therefore, the scientific, medical, and media communities need to be cognizant of this, and to present to the public solidly documented and easy-to-understand pieces of information, particularly those that concentrate on major risk factors, and which avoid sensationalism for its own sake and large amounts of background “noise” static obscuring the most important messages about health and cancer risk.